MANN] 
 
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Cornell University Library 
 SB 608.P65A5 
 
 Report on White pine blister rust contro 
 
 3 1924 002 852 709 
 
BULLETIN No. 2. ^^' p. Mftrtift SECOND EDITION 
 
 REPORT ON f^^^A^ 
 
 White Pine Blister Rust Control 
 
 1918 I 
 
 PUBLISHED BY THE 
 
 AMERICAN PLANT PEST COMMITTEE 
 
 4 Joy Street, Boston, Mass. 
 
 Wilfrid Wheeler, Chairnian 
 Harris A. Reynolds, Secretary 
 
 EXECUTIVE COMMITTEE 
 
 E. C. HIRST, State Forester,^ j. G. SANDERS, State Economic 
 
 Concord, N. H. Zoologist 
 
 W. A. McCUBEIN, Pathologist Harrlsburg, PennBylvania 
 
 Dominion Field Laboratory of Plant WILFRID WHEELER, ^Commissioner 
 
 Pathology, of Agriculture, 
 
 St. Catharines, Ont. Boston, Massachusetts. 
 
 HARRIS A. REYNOLDS, Secretary, H. H. YORK, Professor of Botany, 
 
 MassachuBetts Forestry Association, Brown University, 
 
 Boston, Mass. Providence, R. I. 
 
 COMPOSITION OF COMMITTEE 
 
 The Committee is composed of four members from each State in the 
 United States, and four from each province of Canada, and the personnel 
 so far as practicable, consists of the Commissioner of Agriculture, State 
 Forester, State Entomologist, State Pathologist and corresponding officers' 
 in the Provinces of Canada. Horticulture is generally included under Agri- 
 culture, but in some instances, there ia a Sitate Horticulturist, who is a 
 member of the Committee. 
 
 The membership is limited to four from each State and Province and » 
 in each case the aim is to secure those officials who have most to do with 
 plant pest control. 
 
 PURPOSE 
 
 The purpose of the Committee is to inform the public concerning 
 dangerous plant pests, and to secure measures for their eradication or con- 
 trol. The chief object is to attack effectually, any plant pest in its incipient 
 stages, before it has had time to become permanently esteblished. 
 
 ; 1 
 
TO THE PUBLIC 
 
 White pine blister rust is a destructive fungus native to the Old World, 
 li kills white pine and other five leaved piues by girdlingj In 1915, the 
 blister rust was fouijid on currants and gooseberries in parts of New England. 
 Foresters and pathologists immediately held a conference and organized the 
 Committee on the Suppression of the Pine Blister Bust in North America, 
 now reorganized as the American Plant Pest Committee, which at once 
 secured Federal and State appropriations for fighting the disease. This 
 brief publication summarizes the res^t of the third season's experiments and 
 investigations. 
 
 iN POINTS TO REMEMBER 
 
 ^ 1. The bhster rust cannot spread from pine to^pine. It destroys 
 white pines only after a period of growth on currant and gooseberry bushes, 
 and in no other way. 
 
 2. The destruction of all currant and gooseberry bushes (wild and 
 cultivated, including fiowering currants) is the only successful method of 
 protecting the pines. 
 
 3. All known facts indicate that the maximum distance to which 
 it is necessary to remove currant or gooseberry bushes does not exceed one-' 
 third of a mile, even under the most favorable conditions for infection. 
 Under ordinary conditions a distance of 300 yards between white pines and 
 currants or gooseberries will give much protection, probably sufficient to 
 grow white pine commercially. 
 
 4. Pines of all ages are attacked, but the older the tree the longer it 
 takes to kill it. Young pines, under 35 or 30 feet in height, should be given 
 protection first to insure their reaching a marketable size. 
 
 5. Commercial planting of white pine is practicable, if care is taken 
 to secure uninfected planting stock, and if all currants and gooseberries are 
 destroyed in and around the planting area to a distance of not less than 
 200 yards, and preferably to at least 500 or 600 yards. 
 
 6. Whenever you see a wild 'OJTEEAmT or GOOSEBERRY hush, 
 PULL IT UP, and hang it up so that it cannot grow again. Go over your 
 land systematically until it is clear-. Be sure to pull up the bushes by the 
 roots; do not cut or break them off or they will sprout again. 
 
 7. Cultivated black currants are especially susceptible to the disease, 
 and cause very serious pine infection. In the infected regions, they should 
 ' not be grown within one-third of a mile of white pines. 
 
 8. Spraying will not prevent or cure the disease on currant, goose- 
 berries or pines. 
 
 9. If you suspect the disease on pines, currants or gooseberries, send 
 specimens to your State Forester, State Nursery Inspector, State Agricul- 
 tural Experiment Station, or the Office of Forest Pathology of the United 
 States Department of Agriculture, Washington, D. C. ' 
 
 10. White pine is one of the most valuable and most useful com- 
 mercial trees in North America. White pine growth on lands that would 
 otherwise be waste has paid off mortgages, improved farms, and educated 
 families. Its logging and manufacture provides employment for thousands 
 ,of people. With heavy taxes to pay after the war, we cannot afford to 
 
 lose our white pines. 
 
 2 
 
RESOLUTIONS OF THE COMMITTEE, 191 8 
 
 The fourth annual conference of this Committee was held on November 
 11 and 12, 1918, in the State House, Boston, Mass. Reports on the progress 
 of blister rust control were made by the officials in charge. These reports are 
 much too comprehensive to be given in detail, but a brief compilation, giving 
 the principal facts presented, appears on the following pages. 
 
 The resolutions adopted by the Committee are : 
 
 1. This Committee re-afflrms its position taken at previous meetings, 
 that the responsibility for control of the blister rust must rest finally with 
 the forest owner; but, in ordier to hold the ground already gained, and not to 
 lose the benefits of the excellent work already accomplished in many places, 
 it recommends that Federal, State and Provincial and other public appropria- 
 tions for experimental, demonstration, control, and eradication work in the 
 Eastern States and Provinces be continued, notwithstanding war conditions. 
 
 In the Western States and Provinces, the Committee notes with satisfac- 
 tion that continued scouting has not revealed th6 presence of the blister rust; 
 the Committee recommends, nevertheless, that scouting in these States and 
 Provinces be kept up, and that State and Provincial appropriations be made 
 and Federal appropriations continued to this ?nd. 
 
 2. We recommend that each State may well have three or four district 
 agents trained in educational propaganda, or especially adapted to carry it 
 on, through whom personally the schools and the leading citizens in the va- 
 rious towns can be reached. We recommend that material for publication be 
 prepared and distributed by the State Department having charge of the blister 
 rust work in each state. We emphasize the educational importance of taking 
 land-owners, children and others into the infected areas where practical con- 
 trol methods are being put into actual practice. We also recommend the hold- 
 ing of occasional State Conferences of workers, as a means of increasing effi- 
 ciency. 
 
 3. It is the sense of this Committee that protection from serious Injury 
 of White Pine plantations in localities where Ribes* can be removed is prac- 
 ticable, as far as danger from blister rust is concerned. It is assumed that 
 the trees to be used in all planting have not been exposed to blister rust and 
 have not acquired the disease. 
 
 Note. — This resolution conforms with the resolution passed at the 1917 
 conference, which reads: 
 
 "In addition to eradication of Ribes within a pine area, this Committee 
 is of the opinion from evidence so far obtained that in the future serious loss 
 from a commercial standpoint is not to be expected if the area Is surrounded 
 by a Rtbes-free zone one-third of a mile in width." 
 
 4. With the recent discoveries of the presence in this country of the 
 European Corn Borer and the European Potato Wart disease in mind, the Com- 
 mittee Is more than ever convinced of the immediate and pressing necessity 
 for the exclusion from this country insofar as practicable of all materials 
 likely to introduce dangerous pests. It therefore urges the Federal Horticul- 
 tural Board to exercise its powers to the fullest possible extent. 
 
 The following recommendations of the Committee on Reorganization, Co- 
 operation and Plans for Future Work were adopted: 
 
 1. That the activities of the Committee be extended to cover new and 
 Introduced pests of plants. 
 
 2. That the organization be known as the "American Plant Pest Com- 
 mittee." 
 
 • Note For the sake of brevity and convenience, the botanical name, Ribea, is 
 used In this publication to designate all gpecles of cnrranta and gooseberrleB. 
 
Status of White Pine Blister Rust Control In 1918 
 
 Compiled by Samuel B. Detwilet 
 UNITED STATES 
 
 NORTHEASTERN STATES. War conditions made it impossible to con- 
 duct blister rust work this year on the scale for which plans had been made. 
 Scouting in 1916 and 1917 proved the blister rust to be generally prevalent in 
 the white pine regions of New England and northeastern New York. Infection 
 on currant and gooseberries this year was not as heavy as in the two previous 
 years, apparently due to the dry season. Many new native pine infection cen- 
 ters were found but most of these are of small size. All indications point to 
 a steady increase in the size and number of centers. A comparatively large 
 amount of pine infection is expected in 1919, due to the heavy Ribes infection 
 of 1916. 
 
 Field observations indicate that the bulk of the white pines are as yet free 
 from this disease, but without the removal of adjacent currants and goose- 
 berries it is only a question of time until great damage will be done to the 
 pines. The situation in the Northeast demands that owners should not delay 
 in uprooting wild and cultivated currants and gooseberries to as great a dis- 
 tance as possible (up to a third of a mile) from their stands of white pine. 
 During the past season, many pine owners destroyed wild and cultivated cur- 
 rants and gooseberries with their own labor. Others were equally disposed 
 to co-operate, provided such action would lead to the extension of definite 
 control areas in the community. 
 
 Areas of young pine should receive first attention, since the development 
 of the disease in such areas will prevent the marketing of the pine in ques- 
 tion. However, it must not be forgotten that stands of mature pine are rap- 
 idly replaced by young growth. It appears from present , knowledge that it 
 will be well to scout a control area a second time after an interval of two or 
 three years, to destroy Ribes which develop from seedlings and sprouts. 
 After that it is hoped that the ground will not have to be covered again more 
 than once in five years. 
 
 The prospects for practical blister rust control are favorable. Much has 
 been learned about the best way of handling the whole situation. Proof is at 
 hand that wild currants and gooseberries can be found and destroyed at a cost 
 that is not prohibitive. Continuation of experiments in demonstration control 
 areas will undoubtedly further reduce costs and increase efliciency. The return 
 of men from- the war will relieve the labor situation. Method and discipline 
 count in pulling gooseberry bushes. Nothing but the best work will pay, and 
 the way to insure this is to employ the best men available. All of the North- 
 eastern States have distributed bulletins, circulars and posters and much 
 educational work has been done at fairs and in the schools. This work should 
 be continued for the purpose of extending practical control to pine areas as 
 rapidly as possible. 
 
 MAINE. Most of the work was done in two demonstration control areas 
 located at Klttery Point and Alfred. Both of these areas were covered for 
 Ribes in 1917, but it was thought best to go over them again this year, as a 
 check. A new control area was. established in the town of Brunswick, sur- 
 rounding an area of diseased pines. 
 
 Sixteen men were employed during the field season from June 1 to Septem- 
 ber 30. Six-men crews gave the best results. One acre of swamp at Alfred 
 had 1470 wild gooseberry bushes, requiring 17 hours of man-labor to eradicate, 
 and costing $3.78, the extreme figure. The average labor cost per acre was 
 $0.30 at Alfred, $0.40 at Klttery Point, and $0.25 in the Brunswick area. A 
 total of 4903 acres was gone over during the season and 92,000 Ribes plants 
 destroyed at an average cost of $0.32 per acre. 
 
 Future efforts at Ribes eradication should be confined to the vicinity of 
 tracts of young white pine, where the value of the timber will Justify the 
 expense of Ribes eradication. Local co-operative control should be encouraged 
 and developed so far as possible. An average figure of $0.32 per acre would 
 seem to be a fair one where Ribes are eradicated by Individual landowners. 
 Such an expenditure may well be recommended as protective insurance on 
 young stands of white pine. 
 
 4 
 
No compensation was paid for cultivated Ribes, as most of the plants were 
 diseased and the owners made no claim. Blister rust was not found In any of 
 the commercial nurseries inspected during the season. No general scouting 
 was done, ibut 46 pine plantations containing more than 250,000 trees were 
 Inspected, and suspicious specimens found in two places. 
 
 NEW HAMPSHIRE. In 1917, out of 76 towns which contained consider- 
 able areas of pine Umber land, 8 had infected pines, and 71 had infected cur- 
 rant and gooseberry bushes. In view of these conditions, each town was asked 
 to make a certain minimum appropriation for control of the blister rust. 
 Forty-three towns appropriated a total of $7,125.00 for the purpose. Projects 
 were completed in 30 towns and 959,315 currant and gooseberry bushes were 
 destroyed on 66,652 acres at an average cost of $0.39 per acre. An average 
 force of 70 men were employed in field work from May to October. 
 
 Interest on the part of the private owners was evidenced by voluntary 
 contributions of funds to pay for control work on their own property. In 
 Peterborough alone $753.15 was thus contributed and resulted in the removal 
 of currants and gooseberries from 2038 acres. Such interest on the part of 
 private owners points to possibilities which are of fundamental Importance In 
 making plans for the future. 
 
 The demonstration control area started at Cbnway in 1917 was extended 
 this year Into the town of Bartlett. A total of 53,551 wild Ribes plants were 
 pulled on 1790 acres at an average cost of $0.71 per acre. Scattered pine in- 
 fections were numerous throughout this area; on 2 acres at Dundee, and 2.03 
 acres on the State road, all of the pines were generally diseased. On the entire 
 area, 35% of the Ribes were infected with the rust. Daily records show that 
 48% of the bushes found in June were diseased — 33% in July, and 29% in 
 August. This area was carefully mapped to outline the forest types. Skunk 
 currant predominated in all types except in fields and along highways, where 
 there were more wild gooseberries. Cultivated Ribes were destroyed in the 
 village of Lower Bartlett, 116 bushes being found, all of them infected. It is 
 gratifying to report that no one demanded compensation. 
 
 Checks were made to determine how thordughly the crews located and 
 uprooted wild Ribes. Along 3200 feet of' roadside, in dense undergrowth, 717 
 bushes were pulled the first time over the area, and only 5 bushes the second 
 time. In a half acre of skunk currant growth 539 plants were found the first 
 time and two when the area was gone over again. Careful checking was done 
 on 77 acres of -swampy land covered with hardwood brush 6 to 8 feet high, old 
 slash, briars and berry bushes, which made eradication especially difficult. 
 In spite of this, 34,752 bushes were found in the first working of the area, 46 
 bushes in the second, and none the third. These facts show plainly that wild 
 currants and gooseberries can be found and destroyed by conscientious work. 
 
 VERMONT. Limited scouting in 1918 revealed the presence of well estab- 
 lished native pine Infection in the town of Barnett, and Ribes infection through 
 Rutland, Chittenden and Addison counties. Diseased Ribes were also found 
 at Shrewsbury, Goshen, Randolph, Newberry, Glover, and other points so 
 widely scattered about the State as to indicate very general blister rust infec- 
 tion. 
 
 The undesirability of drawing upon the already greatly diminished supply 
 of farm labor was the chief factor in limiting the work in 1918 to development 
 of demonstration control areas. Four eradication crews of 6 men each were 
 employed during May, June and July on control areas begun in 1917. At South 
 Royalton, 7,313 wild gooseberries were pulled on 75 acres; 9% of the bushes 
 were Infected. On the Downer State Forest Farm at Sharon, 36,468 (99% 
 prickly gooseberries) were removed from 473 acres surrounding the pine 
 plantations. The high average cost of $2.47 per acre Is due to the unusually 
 large number of Ribes and the density of undergrowth. 
 
 The demonstration control area at Thetford was re-scouted. On 3,063 
 acres 25,025 Ribes were pulled, of which 93% were prickly gooseberry, 6% 
 skunk currant and} 2% cultivated currants. Costs ranged from $0.29 per acre 
 In pasture to $1.79 in swamps. The average in 1918 was 8 Ribes per acre at 
 an average cost for eradication of $0.85 as compared with 6V2 bushes per acre, 
 at a cost of $0.63 in 1917. 
 
 The importance of doing the work early in the season cannot be over- 
 emphasized. WildRi hea leaf-out, much in advance of other plants, and ther e- 
 fore are promigent early in the spring. The Ide'ai proceaure woula be (,0 beatn 
 
eradication work as soon as leaves begin to show plainly on Ribes and to 
 complete it before other vegetation has a chance to hide the Ribes bushes. 
 Under this plan, eradication costs would be lowered. The fairest example is in 
 the working of pasture land. In May the average cost per acre was |0.25; in 
 July It was $0.52. ^ ^ 
 
 MASSACHUSETTS. The policy for 1918 was to concentrate i work in con- 
 trol areas. No general scouting was done as the r^ist was known to be 
 prevalent throughout the State. Previous to 1918 diseased pines were found 
 in 72 towns and diseased Ribes in 224 towns. This year infection was very 
 plentiful on Ribes in the control areas, with scattered pine infection present. 
 At the height of the season 8 eradication crews were in the field. The most 
 effective crew organization was , 5 men and a foreman. In some types 6 
 men could be used in the crew, but 7 men proved to be too many, as in thick 
 growth the foreman could not satisfactorily check behind the crew. 
 
 The Barre demonstration area was extended from the beginning made last 
 year. Skunk currants were very numerous in moist places, and wild goose- 
 berries were prevalent throughout the area. On 8,095 acres, a total of 245,636 
 Ribes were destroyed, of which 73% were skunk currants, at an average cost 
 of $0.60 per acre. 
 
 Two sections were chosen to obtain data on selective Jlibes eradication. 
 They were first thoroughly scouted by one man and in the first working the 
 crew traversed only such areas as were thought to bear Ribes. Out of a total 
 of 331 acres, but 53 acres were designated as free from Ribes. On these sup- 
 posedly Ribes-free areas the crew found 686 plants, or 20% of the Ribes on the 
 entire tract exclusive of 10,070 skunk currants which grew on 73 acres. This 
 experiment indicates that in an area where wild Ribes are as generally abund- 
 ant as in Barre, the crews should go over the entire ^.rea in close formation. 
 Possibly some selective system can be worked out in which pine areas form 
 the basis of selection rather than Ribes areas. Also, there are often large 
 areas which are more than 1500 feet from any pine or are so thoroughly 
 screened by vegetation that Ribes would have little or no effect and could! 
 well remain. 
 
 In the towns of Hanover, Halifax, Hanson, Pembroke, Marshfield and 
 Duxbury, 110,957 wild Ribes were uprooted on 10,611 acres, at an average 
 cost of $0.70 per acre. The swamps usually contain many Rdbes and are full 
 of briars which make work diflficult. The upland growth is fairly open, and 
 where there is a cover of scrub oak and blueberries, seems to be free of Ribes. 
 The method of selective Ribes eradication, which was not successful under 
 conditions in Barre, proved satisfactory in the Hanover area. 
 
 Under the recent law compensation was paid for 14,396 cultivated Ribes 
 destroyed in 1917, at the average value of $0.36 per bush. One nursery was 
 found to have a diseased pine. No other nursery was found to have pines 
 or Ribes infected with blister rust. 
 
 RHODE ISLAND. The control area in the town of Coventry was en- 
 larged in 1918 to include part of the town of West Greenwich. Two crews 
 of six men each were employed early in the season, and later one crew. A 
 total of 14,419 Ribes bushes were destroyed on 12,115 acres, averaging l.l 
 bushes per acre. The area is 95% woods and brush, and contains 6,000,000 ft., 
 B. M., of merchantable white pine, in addition to 2,800 acres of pine less than 
 six inches in diameter, the whole conservatively valued at $176,000. 
 
 The amount of the white pine in the State is approximately 65,000,000 feet, 
 worth $650,000; in addition, white pine reproduction has at least an equal 
 cash value. Wild Ribes grow in fairly large numbers in swampy areas in 
 every town in the State. No new pine infections were located this year but 
 Infected Ribes were found in each town. Approximately 3% of the bushes 
 destroyed were infected. 
 
 Eradication costs averaged $0.28 per acre. This is 6 cents per acre less 
 than last year's cost. The, decrease is mainly due to careful scouting of the 
 ground ahead of the crew to mark the boundaries of areas of Ribes growth. 
 The- results obtained show that in Rhode Island a high percentage of Ribes 
 can be eradicated by covering only "Ribes areas." These are principally 
 swamps, pastures, moist hardwood land, fence lines, roadsides, . Dcky ledges, 
 stone walls, etc. 
 
 The crews at first re-scouted a portion of the territory covered each day. 
 
 6 
 
On 15 check plots aggregating 35 acres, 1,009 bushes were found the first 
 time, 51 hushes in re-scouting, and none the third time. This is an effi- 
 ciency of 96.2%. Later, a more accurate system of checking was adopted. 
 The supervisor accurately determined the number of Ribes in a plot. When 
 the crew went over this area they had no knowledge that it was a test 
 plot. Afterward, the supervisor counted the number of bushes remaining. 
 In the 12 tests made during the season by this method, on a total area of 
 nine acres the crew found 853 wild gooseberry bushes and the supervisor 
 found only 21 additional bushes. This Is an efficiency of 97%. 
 
 Checks also were made on the thoroughness of eradication in 1917. On 
 five plots, aggregating 86V2 acres, 848 Ribes were destroyed in 1917, and only 
 six additional bushes, growing along fences and near stone piles, were found 
 in 1918. 
 
 In pastures where sheep were kept no Ribes were found. Ribes were 
 numerous in low land immediately adjoining, but none were found in the 
 ex-tension of the same swamp within the sheep pasture. Birds ~were seen to 
 feed on fruit of wild Ribes and bushes that bore abundantly were completely 
 stripped in less than two weeks. Apparently the majority of wild Ribes 
 seeds are scattered by birds and squirrels. Judging from the abundance of 
 wild Ribes fruit, comparatively few seeds develop into mature bushes. 
 
 About $700 was contributed by individual owners for uprooting Ribes 
 from their pine areas. In co-operation with the State and Federal Govern- 
 ments. Compensation was paid for 103 bushes out of a total of 492 culti- 
 vated Ribes destroyed, at the rate of 31 cents each. The majority of people 
 are willing to destroy their bushes for the welfare of the pines. 
 
 CONNECTICUT. On account of the war, it did not seem advisable to 
 employ men for extensive blister rust work. The control area in the town 
 of Norfolk was not continued this year, and no general scouting or definite 
 crew organization was attempted. Only four men were employed outside of 
 the Experiment Station staff. 
 
 Spraying experiments for the control of the blister rust were conducted 
 on red and black currants. Results were nearly negative on red currants, 
 because of lack of infection. On black currants, spraying gave nearly coin- 
 plete control throughout the season. However, such careful and frequent 
 spraying had to be done that it is not considered to be a practical method 
 of control. At Norfolk, Ribes infection reached its height following a period 
 of hot, moist weather during the week of July 20. 
 
 The owners of two large pine plantations co-operated in eradication of 
 Ribes. A crew of Italian workmen did especially efficient work. The attitude 
 of property owners in the State has been favorable to the work. In the 
 future, local co-operation will be extended as much as possible, with the ex- 
 pectation that ultimately the work will be turned over to private initiative, 
 the State authorities only giving such assistance in supervision as is requested 
 or found to be necessary. 
 
 NEW YORK. Scouting in 1917 indicated a general infection in Ribes 
 throughout the northeastern portion of the State and widely scattered Ribes 
 infection in central and western parts. 
 
 Limited scouting was done in 1918 and infected currants were found 
 near Jamestown, Chautauqua county, eight miles from the Pennsylvania 
 border at Adams, Jefferson county, and Nicholville, St. Lawrence county. A 
 severe pine infection center of more than 100 acres was located at Wil- 
 mington Notch, Essex county. At Lewis, Essex county, the area of infected 
 pines was found to extend 11 miles north and south, instead of six miles as 
 determined in 1917. In Warren county diseased pines were found scatter- 
 ingly over at least 10,000 acres. Two extensive pine infection centers were 
 found near the village of Lake George and a number of smaller infections were 
 found further north, and for some miles west of the lake shore. No infection 
 on Ribes was found at Geneva in 1918, showing that the disease is still under 
 control in that section. ,. , , ,, ^ ^ „, 
 
 This year over a million wild Ribes were eradicated on 15 areas totalling 
 29 337 acres. In addition to cdntrol areas, protection was given to white 
 pine in State nurseries and plantations. The average cost of eradication 
 was $1.46 per acre and required 'an average of 3.62 hours of man labor per 
 acre. From May to October 302 men were employed, though not more than 
 
 7 
 
200 were working at any one time. The best results were obtained from 
 crews of moderate size, preferably six men and a foreman. The men were 
 spaced six to 10 feet apart in the line, depending on the character of the 
 growth. The tendency was to work too far apart rather than too close. The 
 foreman checked the work in the rear of the crews. 
 
 Several types of Rlbes diggers were developed in New York this year, 
 and were used in a number of States, with good results. One had an eight 
 inch head resembling a geologist's pick; one end was pointed and the other 
 flattened for cutting. A heavy, two-toothed hook, resembling the claw of a 
 carpenter's hammer, was welded to a piece of pipe, the latter forming a 
 socket for a strong handle. This tool will stand great strain and is a val- 
 uable time-saver where large bushes" grow. One or two men in each crew 
 carried the heavy diggers, the other men being equippd with the lighter kind. 
 
 The demonstration control area of 9,344 acres, is located in Warren 
 county and includes the village of Chestertown. A large portion is wooded 
 and is typical of the best white pine growth in New York. Ribes infecQbn 
 was abundant and diseased pines were found to be generally distributed. 
 Wild Ribes were plentiful throughout the area, averaging 32.7 per acre, at 
 an average labor cost for eradication of $1.14 per acre. The foremen of the 
 crews were paid $3 per day, and the other laborers $2.50 per day. According 
 to checks made during the season, 92% of the bushes were pulled. There is 
 no doubt that more than 92% of the Ribes leaf surface was removed. 
 
 Observations on the sprouting of Ribes copfirm the opinion generally held 
 jthat wild gooseberries do not sprout if the crown is completely removed. 
 Skunk currant and swamp black currant have underground stems which 
 form a nucleus for a new plant if not removed. The use of Ribes picks is 
 essential if the crown and roots are to be enti);ely removed and sprouting 
 prevented. If the soil is not shaken from the roots when Ribes bushes are 
 pulled, or If the bushes are not hung up to dry out, they will occasionally 
 continue growth. On two acres from which 253 bushes were pulled and 
 thrown on the ground, four had sent up healthy shoots the following year. 
 Bushes with matured fruit, especially In moist ground, must be carefully de- 
 stroyed or the fruit removed to a safe place; otherwise an unusual number 
 of seedlings will result. There is no doubt that many (if not most) Ribes 
 seedlings perish from drouth and winter-killing but enough survive to make 
 it necessary to re-scout a control area after an interval of two or three years. 
 
 Local co-operative control was carried on at Lake George, and Schroon 
 Lake. The Lake George Association subscribed $4,772.50, and has stated that 
 additional funds will be forthcoming when needed. The outlook for this kind 
 of work is encouraging. Ultimately the owners of pine must bear the whole 
 expense of protecting it from the blister rust, and the financial help now 
 asked of them Is a step in that direction. 
 
 The State Department of Agriculture, in 1918, found infected Ribes In 
 two nurseries, and 11,000 black currants were destroyed. One nursery already 
 under quarantine had a single diseased pine. Each nursery in the State has 
 been Inspected two or three times during the season and the surrounding 
 territory was also examined. A total of $629.65 was paid for cultivated Ribes 
 destroyed in the State in 1918. 
 
 PENNSYLVANIA. A total of 2,097,063 pines and 37,134 Rlbes were in- 
 spected this year. A few infected pines were found in two plantations near 
 Reading, and in one near Penllyn. One infected pine was found in a nursery 
 near Philadelphia. No Ribes infection has ever been discovered in the State. 
 Both wild and cultivated Ribes were intensively inspected for several miles 
 around each infected pine plantation. The three infected localities are far 
 removed from native pine and rigid Inspection for the next few years should 
 eliminate the disease. 
 
 NEW JERSEY. Three diseased pines were found in a nursery near 
 Morristown, and one in a nursery near Red Bank. The latter also contained 
 diseased black currants and additional infected black currants were found at 
 three other points near Red Bank. Diseased pines were also found in an 
 ornamental planting near Clementon. All diseased pines and Ribes leaves 
 were destroyed and a strict quarantine is maintained on infected nurseries. 
 
SOUTHERN AND CENTRAL STATES. In states south and west of 
 Pennsylvania, Including Delaware, Maryland, Virginia, West Virginia, North 
 Carolina, Ohio, Illinois, Indiana, Iowa, Kentucky, Tennessee, Missouri, Kansas, 
 Nebraska, South Dakota and North Dakota several thousand plantings of white 
 pine were inspected as well as nurseries growing white pines but no disease 
 was discovered. Particular attention was paid to inspection In the vicinity of 
 former Infections in Ohio, Indiana, Iowa, and South Dakota, and In tracing 
 shipments from diseased nurseries. 
 
 LAKE STATES. In Michigan, eight men made 759 inspections In 71 
 counties. In addition to 240 acres of pine plantings, over 534,000 pines were 
 examined. The blister rust was found this year in only one locality. This 
 was in Birmingham, Oakland county, on French-grown white pines in a nursery 
 and on one pine transplanted from this nursery to private grounds. The infected 
 trees were destroyed, as were all of the trees of this French importation grow- 
 ing in the nursery block. There was no recurrence of infection in or around 
 the nursery near Pontiac, Michigan, where infected pines were destroyed last 
 year. 
 
 In 'Wisconsin, prior to 1918 the rust had been found only in Polk county. 
 This year about 50% of the northern half of the Stat© was scouted in addition 
 to 279 Individual inspections of pine plantings, and pine in nurseries through- 
 out the state. The results of this season's survey show that the disease la 
 present in 10 counties— Polk, Bumette, Washburn, Barron, Rusk, Dunn, Pepin, 
 Shawano, Clark and Marathon. Over 45,000 infected Ribes and 746 infected 
 pines were found in 15 groups scattered over 50 sections in 28 townships. No 
 infection was found in nurseries. 
 
 Native pines were found severely Infected near Rice Lake, in Barron 
 county; at Lewis, In Polk county; and near Falun, in Bumette county. Partial 
 eradication of Ribes has been accomplished in two of these areas and It Is 
 expected that all pines in the disease centers will be destroyed before next 
 Spring. A heavy infection on Ribes In the Menominee Indian Reservation at 
 Keshena apparently indicates a serious pine infection at this point, but it has 
 not yet been located. 
 
 In IVIinnesota an extensive survey between the St. Croix and Mississippi 
 Rivers as far north as Duluth failed to bring to light any rust centers in native 
 pine woods other than those found last year. However, the rust reappeared 
 at 7 former infection centers, viz. : Afton, Pine City, Rock Creek, Pranconia Creek, 
 Rush Lake, and at two places near Harris. All of these points are In the St. 
 Croix Valley, within 12 to 15 miles of the eastern boundary of the state. 
 Elradioation of Ribes has been carried on over approximately 1200 acres in the 
 Rush Lake area. All known plantings of white pines and all nurseries having 
 white pine were examined, and the disease was found in plantings at Rochester 
 and Chisago City. In both places all of the planted stock was destroyed. 
 Diseased pines were also found in a planting at Lake Vadnais, Ramsey county. 
 The area known to have blister ruiSt is smaller by five counties than was the 
 case last year. 
 
 Present knowledge Indicates there is no possibility of completely eradicat- 
 ing the disease in Wisconsin, and this naturally affects the plan of work in 
 Minnesota. In both states, however, it Is believed that Increased efforts along 
 the line of present activity will prevent rapid general Infection of pines, thus 
 giving time to develop control methods adapted to conditions in this region. 
 In both Wisconsin and Minnesota it is the policy to remove all of the pines m 
 and adjacent to pine Infection centers and also, so far as possible, to eradicate 
 Ribes in the vicinity of infections. 
 
 A school campaign In the three Lake States, in September and October, 
 resulted in reports on planted pines, currants and gooseberries, from several 
 thousand school children. No disease was found by this method of scouting. 
 In Minnesota, blister rust exhibits were made at the State Pair and 10 county 
 fairs In the northern part of the State. Posters have been widely distributed 
 in white pine regions, through Postmasters and State Forest Rangers. 
 
 WESTERN STATES. West of the Great Plains less scouting was done 
 this year than In 1917 owing to the Impossibility of securing adequate assist- 
 ance. However, thousands of pines, currants and gooseberries purchased from 
 Eastern nurseries were Inspected, without finding any evidence of the blister 
 
 rust. 
 
 Great interest is being shown in the far western states in preventing an 
 
 9 
 
Summary of Ribes Eradication on Demonstration Control Areas, 
 
 by Types, 1918 
 
 ATBEAGE NUMBER OF RIBES PER ACRE 
 
 CQ EO 
 
 WO .-WO} 
 
 Demonstration „ .»• Sf^ .§'.«.««' 4 S d 2 S S •5 ,r 
 
 control Area lll^S Ǥ gS .H| II g I |s| S^l | 
 
 Alfred, Me 2,848 23.0 39.0 21.0 20.0 4.0 46.0 1,470.0 14;0 19.4 
 
 Klttery Point, Me 1,500 6.2 3.0 4.0 7.0 20.0 9.0 24.0 5.2 20.0' 
 
 Brunswick, Me 544 27,0 31.0 0.0 70.0 22.0 52.0 567.0 1.0 6.0' 
 
 Bartlett, N. H 1,790 28.4 2.6 .6 5.3 18.6 68.3 451.3 5.3 
 
 Thetford, Vt 3,053 8.2 7.5 1.9 12.9 9.5 51.0 2.4 
 
 Sharon Vt 473 77.8 .9 5.3 28.9 281.Q 1,069.0 10.5 
 
 Barre, Mass...:....... 8,095 30.3 35.5 4.1 44.2 31.9 20.6 113.6 10,377.3 3.2 
 
 W. Greenwich, R. I... 12,115 1.4 0.0 .0.0 1.5 .4 0.0 5.5 .2 1.2' 
 
 Chestertown, N. Y.... 9,344 32.7 
 
 AVERAGE LABOR-COST PEE ACRE 
 AVERAGE COST OF RIBES ERADICATION PER ACRE (DOLLARS) 
 
 GQ 
 
 Demonstration ^ •'^ St • a.; 'S«- -o-d 4 S ati B '^ 6 
 
 Control Area ^g£^^-dq§§M§ll ^ | p^| H'S'^ ^ 
 
 H<!-«J ■«!<) OCM >hPh go, W^ P9 CO tcO-a1 Cj «» « 
 
 Alfred, Me..; 2,848 .30 .34 .41 .27 .27 .33 3.78 .32 .15- 
 
 Klttery Point, Me 1,500 .40 .37 ,.51 .33 ,37 .47 .86 .29 1.61 
 
 Brunsxpick, Me 554 .25 .26 .14 .31 .27 .41 1.05 .12 .25 
 
 Bartlett, N. H.... 1,790 .71 .61 .52 .76 .68 .72 ' 3.08 .34 
 
 Thetford, Vt 3,053 .85 .87 1.45 .87 .89 1.79 .29 
 
 Sharon. Vt 473 2.47 .99 .95 2.39 7.28 19.16 .70 
 
 Barre, Mass 8,095 .60 .51 .65 .85 .68 1.10 1.10 13.38 .26 
 
 W. Greenwich, R. I... 12,115 .31 .23 .17 .27 .25 .37 .51 .11 .29' 
 
 Chestertown, N. T.... 9,344 1.14 1.20 1.25 1.20 1.10 1.40 1.60 1.45 1.00 
 
 invasion of blister rust. The hope of saving the western white pine forests 
 (from infection lies in the enforcement of the Federal and State quarantines 
 against five-leaved pines and Ribes. 
 
 DOMINION OF CANADA 
 
 During 1917 only southern Ontario and Quebec were scouted for blister 
 rust, and the disease was found to be quite widespread. In view of the western 
 situation and the danger of transmitting the disease to the western continental 
 pine area, it was deemed advisable in 1918 to scout for the blister rust on 
 currants in northern Ontario and in the western part of Canada. Limited sur- 
 veys weire also made in Quebec and New Brunswick. 
 
 In Quebec, 3 men scouted in September, 1918, finding abundant disease In 
 Portneuf County on the north shore of the St. Lawrence, but none in the 
 Ottawa Valley or along the International boundary. 
 
 Northern Ontario was scouted from Rainy River District (just north of 
 Minnesota) east to North Bay on Lake Niplssing, without finding any trace of 
 the disease. Reports through schools from 291 Ribes plantations in Nipisslng, 
 Perry Sound, Sudbury, and Muskoka Districts, and Hallburton County; and a 
 thorough examination by the Agricultural Representative of the Canadian 
 Copper Company at Sudbury, revealed no sign of the rust. At Caernarvon in 
 Haliburton County, the northern limit of the disease In 1917, there was no 
 sign of rust this year. 
 
 Southern Ontario was not thoroughly scouted this year except in the 
 Niagara Peninsula; here the rust was found to be plentiful as usual, being 
 reported in 50 out of 92 plantations. There are further reports from near St. 
 Williams in Norfolk County (119 miles from Port Huron, Mich.) and Lindsay 
 (Victoria county), Bowmanville (Durham county) and the Carillon Region near 
 Montreal. 
 
 Scouting for thie disease on Ribes was carried on during the latter part of 
 the summer in New Brunswicit, IVianitoba, Sackatchewan, Aiberta, and British 
 Columbia; no rust was found. 
 
 Mr. W. J. K. HarkneBs reported that in Manitoba out of every 10 country 
 farm houses, 4 have wild Ribes (always black currants, 1 to 25 plants), I has 
 
 10 
 
ciUtivated RIbes (2-18 black currants. 2-25 red currants, 2-12 gooseberries) 
 wnile the other 5 have no Ribes whatever. 
 
 In Saskatchewan, west of a line north and south through Regina, there Is 
 a much larger percentage of people growing cultivated Ribes (in about the 
 same number per farm as In Manitoba). In the towns and cities of both 
 Provinces there are very few plantations of Ribes, these being practically con- 
 fined to three of four market gardeners in each town who have 25-200 black 
 currants, 25-200 red currants and 12-25 gooseberries. (Excepting Prince Albert, 
 where Ribes are grown in a great number of private gardens). In many of the 
 small towns no Ribes are grown. 
 
 Wild Ribes (black currants) are quite continuous from Ontario to 
 Saskatchewan, occurring In practically every part of Manitoba, growing in the 
 woods, along the streams and ravines, as well as under partial cultivation in 
 about 40% of the farm gardens. In southern and central Saskatchewan there 
 are very few wild Ribes, but along tlie Northern ravines and woods, over the 
 Pasqula Hills around Prince Albert and Battleford, they are quite prevalent, 
 as well as being grown in many of the farm gardens of this Northern district. 
 Apparently wild Ribes are continuous through Saskatchewan from Manitoba to 
 Alberta, by way of Prince Albert and Battleford. 
 
 Since the blister rust is admitted to be ineradicable from Ontario and 
 Quebec at present, three small control areas were established in these two 
 Provinces, to determine whether white pine can be grown successfully In 
 areas where the disease is present. These areas are representative of the 
 sections known .to be affected by the disease; No. 1, with abundant native and 
 wild Ribes, Is on the Niagara Peninsula near Fenwick; No. 2, with scattered 
 wild Ribes in woods and a few cultivated bushes around farm houses, is at 
 Bowmanville on the north shore of Lake Ontario ; ang No. 3 representative of 
 the forest situation where there are wild Ribes but no cultivated ones, is at 
 Carillon, near Montreal. 
 
 The rate of eradication of Ribes per eight hour day per man varied 
 from 1.44 to 9.60 acres for Control Area No. 1; from 0.58 acres to 1.75 acres 
 In Area No. 2, and from 1.12 to 5.97 acres for Area No. 3. The average num- 
 ber of wild Ribes per acre ranged frOm four to 81 In Area No. 1; from 29 to 
 738 in Area No. 2; and from 10 to 197 in Area No. 3. Attempts were made 
 during the course of the work to estimate its efficiency in various ways. The 
 number of Ribes removed in the check, in efficient work should not be more 
 than 2 or 3 per cent, of the total number of Ribes found, where the plants 
 are at all plentiful. 
 
 The system of covering ground in Ribes eradication which will give the 
 best results must be worked out for each gang of men and will somewhat 
 depend on the nature of the ground. Various methods have been tried, from 
 the four man cover and one man check system, down to one man cover and 
 one man check. In the latter system each man checks what the other man 
 has covered. For careful work it would appear that the two man' cover and 
 one man check has great advantages. 
 
 Scientific Research and Field Investigations in 191 8 
 
 Investigations in the United States Department of Agriculture 
 ^ By Dr. Petley Spautding 
 
 The following statement is a summary of the reports given at the meet- ' 
 ing by members of the Office of Forest Pathology, Bureau of Plant Indus- 
 try, U. S. Department of Agriculture. 
 
 The scientific studies of white pine blister rust in 1918, were carried on 
 principally at Block Island, R. I.; Kittery Point, Me.; North Conway, N. H.; 
 and Lewis, N. Y. One person was kept throughout the season at Block Is- 
 land, one at Kittery Point until the latter part of July, two at North Con'- 
 way all the season and three the latter part of the season, two at Lewis 
 practically all the season. At North Conway, Dr. H. H. York, of Brown 
 TTniversity, had charge of the work, and at Lewis, Dr. L. H. Pennington, of 
 Syracuse TTniversity, had general oversight of the investigations. 
 
 Special efforts were made by means of spore traps and by scouting to 
 
 11 
 
get definite information on the distances that spores may be carried. Cur- 
 rents of air are evidently the chief agents of distribution of these spores. 
 Aeciospores were found in traps at an altitude of 2,700 feet above the nearest 
 known source of the spores which was five and one-half miles distant. Spore 
 traps 20 feet above the fruiting cankers caught many more aeciospores than did 
 traps at either side or below, showing the extreme lightness of these spores. 
 
 The investigations at North "Con^ay-'ana^Eewls have sEown conclusively 
 that the spores produced upon pine are much more widely distributed than 
 has been previously supposed. A considerable amount of data from other 
 localities and previous years tends to support this fact. These spores are 
 spread 'for^ miles, starting scattered infections upon Ribes over great areas. 
 It was also' fouad~thar a la,rger percentage of these spores germinate ttian 
 is the case with any of the othCTS. M' ore6ve'f.''tEey retain this pow gr_of 
 gBfmmaS5alf2j_3lPtrl0.d of "^ome weeks. All these facts taken together 
 show that the disease spreadsTaf~aM'"wide" by means of the spores produced 
 upon pine. 
 
 On the other hand it was found that the early summer stage upon Ribes 
 is not widely distributed as had been previously supposed. In the work at 
 North Conway and Lewis with spore traps, as well as other experiments 
 for the purpose, the uredospores were found one to three hundred yards dis- 
 tant. They retain their power of germination a somewhat shorter time than 
 do the spores upon pine. This experience with Cronartium Hbicola is ex- 
 actly parallel to that of other investigators with the other species of 
 Cronartium. It is possible that a season of more moisture may give us some- 
 what different results with the spread of the uredo stage. This, however, 
 remains to be seen. 
 
 The season of 1918 was one of drouth through the latter part of the 
 summer at Lewis where special attention was given to observations upon 
 the spread of Ribes infections. A study of the generations of uredospores 
 made at Lewis show that a period of several rainy days is followed in due 
 time by a new generation of these spores. In 1918 only seven distinct gen- 
 erations were produced at Lewis. 
 
 Studies upon the spread of the disease from Ribes back to pine are not 
 in as satisfactory a condition as with the two preceding stages. McCubbln's 
 data published a year or so ago was to the effect that heavy infection of 
 pines, did not take place at. any_^great distance from the Ribes, a distance of 
 one or two hundred, yards, being Jthgjlmit. Our limited observations show 
 somewhat similar results. At Lewis, N.~"Y., viable sporidla were not abundant 
 during the warmer part of July and August. They were very abundant dur- 
 ing September and thereafter. Sporidla were found frequently upon spore 
 traps near infected bushes but not at a greater distance than two hundred 
 feet even when infection was very heavy. In no case was infecUoa--fbund 
 upqn pinea as far .a g two hundred jeet froia ffibes. ' 
 
 The width of the Ri hfisJree zone necessary to protect pin«s~wlU vary 
 from MlTToTW^^y^ds according tg_coMltIons. The _width " f th^ ^ ynna la 
 laiSgQQn6gI25xImMI]^lo£OgrapMcaUJeatureSr.j^^ 
 
 windsat ^ the time the sporidia are jrpduced, humidity,,„age of the pines, ex- 
 posure a.nd_sjpecie_of_Rlljfis (i.3.3!Eether_in_c^enjplac€s or screened beaeath 
 vssetMieii,— andl4£e_-iKmip0sitIaai_^ighta^^ be- 
 
 tween Ribes -and._Bingi Tests made" by TJfTYork and his assistants sTiovrthat 
 the sporidla produced upon the telial columns are very short lived' — ^being 
 hours rather than weeks in duration. This indicates that moisture conditions 
 (favorable or unfavorable to the development of the spores on the pines) 
 may determine very largely the amount of pine infection and the distance 
 to which Ribes can infect pines. While they are apparently of such a nature 
 as to be easily blown about, this shortness of life may prove to be a factor 
 in determining the width of the Ribes-free zone for protecting pine areas. It 
 Is jDelieved that und6r_orflto.%EZ- -.cfflB(Utiaiis.Jha. width of .ttia--sa£aty^zsng_m.?iy 
 be. c6nsiderablyT^5r5hau one-third ,,af a_ mile ahdyet a nier©hantablB ■stand 
 of pine^be secured wlthin.,a .protected area. A large scale experiment has 
 been made' in the region of general infection for the purpose of securing 
 definite data on this point In a practical way. 
 
 It is believed that the over-wintering of the fungus in the uredo stage 
 
 12 
 
upon Ribes has been demonstrated. Dead leaves, which were heavily in- 
 fected last fall and -which had remained on or under the bushes all winter, 
 were secured early in the spring (March) and positive results were obtained 
 when inoculations were made with the uredospores remaining upon them. 
 (Published in Phytopathology in December, 1918, Vol. 8, No. 12, pp. 617-619.) 
 
 Healthy white pines, planted on Block Island in the spring of 1916, among 
 heavily infected Ribes, produced a number of blisters in the spring of 1918, 
 making an incubation period of 18 months. In a pine plantation._ near Lake 
 Clear Junction, N, Y.,J^e disease has been plrgvalint^ singe^ 19oi^_wlth several 
 cases -of-a-pparent primary infeetionr at least one of" which had not fruited 
 prior to 1917. This i» an incubation period of IB years and illustrates the 
 persistent nature of the dormant disease in the pines. 
 
 A Cronartium upon Ribes has been known to occur in Colorado for a 
 number of years. It has been considered by some to be the same thing as 
 the European white pine blister rust in the Eastern States. Investigations 
 carried out during the past two years under the direction of Dr. G. G. Hedg- 
 cock have shown that it is distinct from Cronartium ribicola and it has been 
 named Cronartium occldentale. It does not attack the five-leaved pines 
 but is known to attack only the pinon pines, Pinus monophylla and Pinus 
 edulis. It has been found to range from the southern portion of Wyoming 
 into Arizona and New Mexico. A comparative statement of the characters 
 of this and of Cronartium ribicola is published under title of "Plnon Blister 
 Rtist" in Journal of Agricultural Research (Vol. 14, No. 10, pg. 411-424, Sep- 
 tember, 1918). 
 
 Investigation in the Canadian Department of Agriculture 
 By Dr. W. A. McCubbin 
 
 The field laboratory of Plant Pathology, Division of Botany, in the Do- 
 minion Department of Agriculture, 'in the summer of 1917, made a deter- 
 mination of the rate of fall of uredospores in still air. The conclusion was 
 drawn that the spores could be carried long distances, since they fall through 
 still air at the rate of about eight feet in five minutes. The same apparatus 
 was used in the spring of 1918 to determine the rate of fall of aeciospores. 
 It was found that the rate of fall was practically the same, that they fell a 
 Uttle over eight feet in about seven minutes. It is therefore apparent that 
 we may expect a very wide distribution of aeciospores. In this connection 
 it may be stated that an estimate was made of the probabilities of aeciospore 
 dispersal from the Fonthill district. It was calculated that if the aeciospores 
 in this neighborhood were distributed over a circle of 10 miles radius there 
 would be about 25 spores per square yard. 
 
 In addition to the above, Geo. H. Duff of this laboratory has continued 
 his work on the effect of light. He has found that sunlight, deprived of its 
 ultra-violet content by filtering through glass has a neglible effect on arti- 
 ficial germination, even with exposures of five hours. Both aecidiospores 
 and uredinospores readily fall victims to ultra-violet radiations, however, at 
 an exposure of two and a half minutes to the radiations from a source whose 
 ultra-violet energy may be represented by 38. The ratio of the ultra-violet 
 energy of the sun to that of this source has been found, by one worker, to 
 approximate 16.38, and since others have shown that a rough direct relation- 
 ship exists between the ultra-violet energy of a source and its physiological 
 effect, it is concluded that a comparatively short exposure (10 to 15 min- 
 utes) to full sunlight would be sufficient to inhibit artificial germination. It 
 is recognized that this does not necessarily postulate inability to infect, and 
 that since it is operative only during the day, this factor cannot be consid- 
 ered as of prime Importance. 
 
 A survey of pine infection areas was made In order to obtain evidence 
 as to the actual damage which has been brought aliout by the disease. This 
 survey covered 35 plantations in three districts, and Involved the examina- 
 tion of 14,428 young pine trees, 10 feet in height and under. In the Niagara 
 district the disease was most prevalent. In the 22 woodlots examined here 
 the disease was found in 19. Out of the 11,579 pines examined 270 were 
 found to be diseased. This gives an average of 2.3% Infected trees, and is 
 
 13 
 
\ 
 
 apparently very small. It is to be noted, however, that the highest record 
 percentage of infection was 33.54 and in at least two other cases where the 
 percentage is 20 or under, the estimate 'was made in woodlots from which 
 a very large number of young trees had been removed. 
 
 Prom our knowledge of the disease here in past years which gives a fair 
 Idea of the time the disease has been present in each locality it would seem 
 that under average conditions the disease attacks about 1% of pines per 
 year. This is extremely low when one considers the Ribes situation in the 
 Niagara Peninsula, and from it one may obtain cheering prospects for future 
 control measures. In the 10 plantations examined at Oakville, where the 
 disease has been present since 1915 at least, only one diseased pine was 
 found out of 2,249 examined, and in Simcoe county where a center of in- 
 fection had existed since 1912 at least, no diseased pines could be found in 
 the three plantations examined, covering 600 pines. 
 
 It is apparent from the results of this survey that three factors are 
 
 Y concerned in infection of pines : 
 
 \ (a) The nearness of cultivated Ribes, particularly black currants. 
 
 (b) The number of wild Ribes present. 
 
 (c) The moistness of the situation. 
 It has been found that on swampy land wild Ribes are plentiful, luxuriant 
 
 and become infected very completely, while on higher and drier situations, 
 they are less plentiful and the infection is often negligible. 
 
 Artificial Infection of Ribes Species and White Pine With 
 
 Cronartium Ribicola 
 
 By Dr. G. P. Clinton 
 
 The observations reported here are the more interesting of the varied 
 investigations on the life history of Cronartium ribicola carried on during 
 the past two years by the writer and His associate. Dr. Florence A. McCor- 
 mlck, at the Connecticut Agricultural Experiment Station. 
 
 1. Artificiai infection of Ribes Species Grown in Crocks. 
 
 Out of 140 Inoculation experiments with 29 species and varieties of Ribes, 
 infections were secured in one or more instances with all but five The aecial 
 spores were successful in 68 out of 86 tests and the uredlnial in 30 out of 54. 
 Very similar results have already been reported by Spaulding and Gravatt 
 The most convenient method of producing successful and abundant infec- 
 tion was by use of small Ribes plants grown in ordinary greenhouse crocks, 
 with superfluous branches and leaves removed. For infection with aecial 
 spores, spores from infected white pine were shaken off into a battery jar 
 containing eight to 10 inches of water. By placing tissue paper over the 
 top of the crock to prevent falling out of the earth and then Inverting and 
 immersing the plant in the water, the upper and lower sides of the leaves 
 were abundantly covered with spores. The plant was then placed in a moist 
 chamber or Wardian case for a few days, and later was more exposed in 
 the greenhouse. Usually within eight or 10 days the uredinial sori began 
 to show on the leaves. On some hosts, especially on Ribes nigrum, the leaves 
 eventually became abundantly covered with these while in others, only an 
 occasional sorus appeared. 
 
 (2) Artificial Infection of Detached Ribes Leaves in Petri Dishes. 
 
 The most successful way was to wash the leaves well in running water, 
 and then place a single leaf in the top of the petri dish, partially filled with 
 water, with the lower side up and held above the water by glass rods or sus- 
 pended on rubber bands stretched across the bottom dish. After the spores 
 had been scattered on the exposed surface of the leaf, the covered dish was 
 placed in rather bright light. The water tends to collect on the cover thus 
 keeping the leaf moist, with conditions very favorable for spore germination 
 and infection. By this method it was possible to trace the germ tubes of both 
 aecial and uredlnial spores through the stomates into the leaf tissues, showing 
 that infection takes place In this manner rather than by directly piercing the 
 epidermis. By this method out of the 35 different Ribes species In 95 tests tried, 
 
 14 
 
25 species were infected; with aecial spores 24 out of 36 tests, and with 
 uredlnial spores 40 out of 59. Infection was, on the whole, even more abundant 
 than by immersion, considering the number of spores used. Immature sorl 
 were seen within 6 days and 22 hours after aecial spores were placed on the 
 leaves; while on the plants In crocks 7 days and 18 hours was the earliest 
 record. Success was obtained In maturing several other rusts on leaves in 
 petrl dishes, and it is believed that this method merits further attention by 
 mycologists. 
 
 (3) Infection of Pines Through the Leaves. 
 
 It has been an open question how the plnfes are Infected from the tellal 
 stage and what are the earliest visible signs of Infection, since It is only after 
 a year or two that botanists have been able to surely recognize Infected plants 
 through the swollen stems. To determine this point, experiments were carried 
 on chiefly In the greenhouse with plants one to three years old, and under 
 conditions where they could be watched very closely. The first Infections 
 were made In the fall of 1916, and were not closely watched, but six months 
 later definite yellow spots showed on certain of the leaves and there was, as 
 well, a slight swelling of the stems. This suggested Infection through the 
 leaves, and the Infections made in the fall of 1917 were watched more closely 
 with the result that ^le^flrstJdsJWe sians_qt_infection wersihese same yellow 
 spots on thejjayes tiefpre any sign af.swelUng^jQr discoloration" of the stems. 
 Infections made in the fall of 1918 have absolutely confirmed 'these observa- 
 tions. Magnified by a hand lens, infection of the leaves was detected by these 
 yellow spots even before they were large enough to be seen by the naked eye; 
 and, m^ne^ase; was found_,\!vlthin..25jda>a-attep the,.telia_wllJi_sfW^t^^ 
 placed on thejeaves. The spots are quite characteristic in color, being agoTaen 
 yeTtov^'~In~contrast with the whitish, greenish-yellow or reddish-brown spots 
 so common on leaves. At first they show only on the side of infection and 
 directly under the stomates, but with time form a distinct band around the 
 leaf, rarely over a quarter of an inch long. It- has -been definitely .determined, 
 that iniecUan.-ofJiLejune-Bee4lMj_akea-:ElafiailinMigh-^^ 
 
 Microscopic sections have shown these golden-yellow spots always to be 
 filled with a sclerotial mass or masses of mycelium more or less closely sur- 
 rounding the fibro-vascular system. In time, strands of mycelium can be 
 found running lengthwise near the bundles down the leaf Into the stem. These 
 cause no discoloration of the leaf. The spots may occur any place on the leaf 
 and there may be more than one to a leaf, if Infection has been fairly abun- 
 dant. Infection may possibly take place through other parts of the plants than 
 the leaves, though as yet we have not been successful in our attempts to se- 
 cure Infection through the young stems, unopened buds, etc. 
 
 Within six months after infection we have had the plants oozing out the 
 pycnlal spores, which is much earlier than noted heretofore, but as yet we 
 have had no plants mature the aecial stage. This may be due to the fact that 
 most of our plants, being young, have been killed by the fungus, so that we 
 have had none under observation that have been Infected two years and only 
 half a dozen that have been Infected over a year. 
 
 Progress of Experiments for Destroying Ribes with Chemicals 
 
 By Dt. W. S. Regan 
 
 Tests begun In 1917 to determine the comparative economy and efficiency 
 of destroying Ribes by chemical means, while still Incomplete, have given 
 encouraging results. Under ordinary conditions, hand pulhng appears to be 
 most practicable, but In certain cases the chemical method offers distinct 
 advantages over hand work. This applies especially to areas of dense skunk 
 currant growth, to large firmly-rooted wild gooseberry bushes and to Ribes 
 growing In stone walls and among rocks, where it Is difficult to uproot the 
 plants and cost of hand pulling is excessive. 
 
 Undiluted fuel oil applied as a fine spray to foliage and twigs has proved 
 the most satisfactory foliage spray. A single thorough application of fuel oil 
 produces defoliation and under favorable conditions it penetrates the bark and 
 kills the plants. Ribes growing in direct sunlight are acted upon more rapidly 
 and are more certain to be killed than those growing under shade. Since 
 
 15 
 
skunk currants usually grow in shade, a single fuel oil treatment cannot -be 
 relied upon to kill all of the plants. The area must be gone over twice, possi- 
 bly three times, to destroy new shoots and plants that survive earlier treat- 
 ment. In direct sunlight about 4 days is required to defoliate skunk currant, 
 while in shade, it requires from 12 days to- two weeks. If rain occurs shortly 
 after the oil is applied, the foliage is killed but buds and twigs are much less In- 
 jured. Individual plants vary in resistance. 
 
 Other less effective foliage sprays tested include sodium arsenite, salt 
 solution, kerosene and several compounds, submitted by the Sterling Chemi- 
 cal Company. One of the latter offers ^promise and may later be improved. 
 E^en in 1 to 60 strength, it killed the foliage of skunk currants in 5 hours and 
 in sunny exposure, 1 to 40 strength killed the foliage in 15 minutes. A heavy 
 rain five hours after treatment did not affect its efficiency. However, this spray 
 requires constant agitation to insure uniform killing effects, does not cling to 
 the glossy leaves of plants growing in sunlight long enough to kill them, and 
 has little effect on buds. For these reasons, fuel oil is superior. 
 
 A number of tests were made with liquids and oils applied at the base of 
 bushy Ribes plants (such as red and black currant and wild gooseberries) so 
 as to thoroughly drench the crown. Dip oil has given most satisfactory results 
 In this method; a single treatment may result in the death of a plant, but 
 many factors over which the operator has no control may Interfere with the 
 efficiency of the treatment. It has not yet been determined whether this 
 method is cheaper than spraying the foliage. 
 
 Summary of the White Pine Blister Rust Situation 
 By Dr. Haven Metcalf 
 
 1. The work to date has proved that wild currants and gooseberries can 
 be found and destroyed. The cost per acre is low^ — cents rather Ihan dollars — 
 and will not compare with the cost of the damage if the bushes are permitted 
 to remain and spread infection to the pines. 
 
 It appears that even under war conditions the local eradication of Ribes is 
 financially practicable. Under peace conditions the cost of such eradication 
 will inevitably be materially lowered. 
 
 2. The demonstrated lo:«ir cost of Ribes eradication is sufficiently encour- 
 aging to warrant the resumption of the planting of white pine in the East. It. 
 must be clearly understood and noted, however, that such planting should. 
 only he undertaken with seedlings of known antecedents which are beyond all 
 possibility of doubt free from the blister rust. Ribes must be eradicated from 
 the planting area in advance of the planting; and the plantations kept free 
 from Ribes during subsequent years. 
 
 3. It Is evident that in the East more and more stress must be laid upon 
 local control. The response of private owners, towns ,and associations, in the- 
 way of active financial support is most encouraging. 
 
 4. The results of continued research on the disease are on the whole en- 
 couraging. The now demonstrated fact of over-wintering of the disease on 
 
 I Ribes, both in the field and In a dry condition, has confirmed the wisdom of 
 State and National quarantines. The distance of spread from Ribes to pines, 
 is more often less rather than greater than has been supposed. 
 
 5. Continued scouting in the far West has failed to demonstrate a single 
 case of introduction of the blister rust. While this fact is encouraging the 
 scouting must be continued both by the United States and Canada. The value- 
 of the 5-needled pines in the West, mainly sugar pines and western white pine, 
 is approximately $177,000,000. This amount of property is worth saving. 
 
 6. Quarantines both State and National, which are now enforced against 
 the trans-shipment of pines and Ribes must continue to be rigidly enforced for 
 an indefinite period. 
 
 7. We may congratulate ourselves, not on the measure of success with 
 which our work has been carried out the past season but upon the fact that 
 we have been able to work at all. The loss of men due to the draft, to war indus- 
 tries, the difficulties of housing and lodging, general increased expense of the 
 work, the poor quality of much of the available help, and during the last two 
 months the epidemic of infiuenza— all have greatly increased the difficulties ot 
 our work. 
 
 January 2, 1919. 
 
 16 
 
BULLETIN No. 4. 
 
 REPORT ON 
 
 White Pine Blister Rust Control 
 
 1919 
 
 PUBLISHED BY THE 
 
 AMERICAN PLANT PEST COMMITTEE 
 
 4 JOY STREET, BOSTON, MASS. 
 
 A. W. GILBERT, President 
 HARRIS A. REYNOLDS, Secretary 
 
 WHITE PINE BLISTER RUST CONTROL IN 1919* 
 
 By Samuel B. Detwiler 
 
 The Fifth Annual International Blister Rust Conference was held at 
 Albany, New York on December 8-9, 1919,. under the auspices of the 
 American Plant Pest Committee. Foresters and pathologists representing 
 the New England States, New York, Pennsylvania, Wisconsin, Minnesota, 
 and Canada were present. The sessions were full of interest, and left no 
 doubt that practical and effective measures for the control of white pine 
 blister rust have been developed during the past four years of experimental 
 work. A summary of the report follows : 
 
 1. Experiments conducted on an extensive scale since 1916 demon- 
 strate that white pine blister rust can be controlled locally by destroying 
 wild and cultivated currant and gooseberry bushes within a comparatively 
 short radius of the pines. A distance of 200 to 300 yards is sufficient to 
 prevent serious damage under average forest conditions. This reduction 
 of 50 per cent in the minimum width of the safety zone hitherto recom- 
 mended, is based on the results of four years' scientific and practical field 
 studies. 
 
 2. Unskilled laborers can be quickly taught, under trained super- 
 vision, to find and destroy at least 95 per cent of the wild currant and 
 gooseberry bushes in going over the ground once. The State crews made 
 642 checks to detepdine the thoroughness of eradication, going over the 
 areas repeatedly until no bushes could be found. A total of 246,254 
 bushes, or 96.4 per cent, were uprooted in the first working, 8095 bushes 
 in the second working, 905 in the third, 125 in the fourth, and 10 in the 
 fifth time over the grdund. Federal and State inspectors made many 
 
 •Paper read at the meeting of the American Plant Pest Committee, St. Louis, Mo., December 
 29. 1919. 
 
additional checks which prove that the crews destroy an average of more 
 than 95 per cent of the bushes in the first working of an area. 
 
 3. Wild currants and gooseberries do not reproduce rapidly in an 
 area that has been worked by an efficient crew. Thorough checking on 
 2485 acres in 8 separate tracts previously gone over by eradication crews, 
 showed that on an average acre, 62 bushes (95.5 per cent) were destroyed 
 in the first working and 3 bushes in the second working. Of the latter, 
 two bushes were missed in the first working, and one bush developed from 
 seeds or sprouts. Bushes missed by the crews usually are small plants 
 growing in underbrush. Such plants have less leaf surface than the aver- 
 age plant; therefore the total percentage of protection to the pines is con- 
 siderably greater than the total per cent of currant and gooseberry bushes 
 destroyed. Judging from data at hand, control areas usually should be 
 gone over again 5 to 10 years after the first working. 
 
 4. No new pine infections could be found in 1919 on four control 
 areas on which currants and gooseberries were destroyed in 1916 and 
 1917. This demonstrates that eradication of currant and gooseberry 
 bushes is successful in controlling the blister rust. The crews working in 
 1916 and 1917 missed a greater percentage of the bushes than crews 
 using the present improved eradication methods and implements. The 
 results show that even though every bush is not removed, enough can be 
 destroyed to insure practical control. 
 
 5. The cost of eradicating currant and gooseberry bushes in the 
 North-eastern states in 1919 averaged 42 cents per acre for labor, or 54 
 cents including supervision. In 1918, the average cost, including super- 
 vision, was 66 cents per acre. In the New England States, the average 
 labor cost was reduced from 44 cents per acre last year to 24 cents per 
 acre this year. This low cost was obtained by emplojang scientific methods 
 in locating wild currant and gooseberry bushes. Costs are expected to 
 be still further reduced in areas where wild bushes are very numerous, 
 as a result of successful experiments in destroying such bushes by spraying 
 them with chemicals. 
 
 6. Blister^rust in fection on pine in the northeastern states is in- 
 creasing rapid ly. A strip survey m one locality in New Hampshire indicates 
 that one-fourth of the pines on an area of 72 square miles are already 
 infected with the rust. The disease is widespread in Minnesota, Wisconsin, 
 Ontario, and Quebec. There is abundant evidence of the destructivenes^ 
 of the blister rust to merchantable trees as well as young white pine stands. 
 This destruction is caused by infected currant and gooseberry bushes near 
 the pines. The longer such bushes remain, the more rapidly pine infection 
 increases. After several years, all of the trees becomes infected and 
 gradually die. Timber owners in infected regions who do not destroy 
 currant and gooseberry bushes within 200 to 300 yards of their white pine 
 stands will suffer serious loss. 
 
 7. Assistance to individual pine owners, towns, and associations in 
 protectmg pme areas from the blister rust is given by the New England 
 States, New York, Wisconsin and Minnesota, in cooperation with the 
 
 2 
 
United States Department of Agriculture. In 1919, about $10,000 was 
 subscribed for cooperative eradication of currants and gooseberries by 
 individuals and associations in New York. In Massachusetts, local co- 
 operators furnished $1,075. In New Hampshire, 53 towns voted appropria- 
 tions totaling $8,514, and 34 individuals and firms subscribed $2,053 
 additional. The interest of the public in blister rust control is further 
 evidenced by the fact that this State destroyed 21,171 bushes of cultivated 
 currants and gooseberries belonging to 1,023 owners, and only 3 owners 
 insisted on compensation for their bushes. The others willingly gave 
 their currants for the safety of the pines. 
 
 8. Owners of young white pine stands in infected regions should 
 hasten to remove currant and gooseberry bushes (both wild and culti- 
 vated) within at least 200 yards of their pines, to prevent greater damage 
 than has already occurred. The blister rust is an insidious disease. A 
 tree usually is severely diseased before the infection becomes noticeable. 
 Cultivated black currants are especially susceptible to the bl ister rust, but 
 all kinds of currants and gooseESriEsrwi-ll-earUse' serious damage to white 
 pines if the bushes are not destroyed before they are infected. Each year 
 these bushes will cause rapidly increasing damage, since each year they 
 become more and more heavily infected from the adjacent diseased pines. 
 At the present time the blister rust is just beginning to make rapid head- 
 way. If owners of white pine in infected regions uproot currant and 
 gooseberry bushes now, they can save their pines. A few years delay 
 will mean serious loss. It is a simple and practical precaution to destroy 
 the currant and gooseberry bushes before they destroy the pines. The 
 demonstrated effectiveness of this method of control justifies pine owners 
 in uprooting currant and gooseberry bushes on a large scale. 
 
 9. Cultivated currants and gooseberries should not be planted in 
 localities where white pine is an important tree. The laws of some states 
 prohibit the planting of such bushes without permission from state author- 
 ities, except in areas designated as "currant growing districts." White 
 pine plantings are a safe investment if currant and gooseberry bushes are 
 first destroyed within 200 to 300 yards. The cost of protection may be 
 reduced by selecting planting sites as far removed from cultivated cur- 
 rants and gooseberries as possible, and where the wild bushes are naturally 
 few or absent. Cultivated black currants may cause loss if within a mile 
 of the pines. 
 
 10. White pine blister rust has not been found in the western half 
 of the United States or western Canada. The abundance of wild cur- 
 rants and gooseberries in the sugar pine and western white pine forests 
 would make control of the blister rust difficult, if not impossible, in most 
 localities. The principal safeguard of these valuable western forests lies 
 in the strict enforcement of the Federal quarantines prohibiting shipment 
 of 5-leaved pines, and currants and gooseberries to points west of the 
 Great Plains. 
 
 3 
 
RESOLUTIONS 
 
 Adopted by the Fifth International Blister Rust Conference, 
 
 Albany, N. Y., Dec. 8 and 9, 1919 
 
 Whereas the white pines are the most valuable forest trees in North 
 America in respect to high stumpage value, rapid growth, general utility, 
 ability to reproduce naturally, and ready adaptability for forest and orna- 
 mental planting, constituting a timber crop with an annual value of not 
 less than $80,000,000, and representing a total value in excess of $1,100,- 
 000,000, and 
 
 Whereas, the white pines are seriously menaced by the white pine 
 blister rust, an imported parasitic disease which attacks pines only after 
 an intermediate growth on currant and gooseberry bushes, and 
 
 Whereas, it has been demonstrated that the blister rust can be con- 
 trolled by destroying wild and cultivated currant and gooseberry bushes 
 in and adjacent to pine stands, and that such bushes can be found and 
 destroyed at low cost. 
 
 Therefore, the Fifth International Blister Rust Conference urgently 
 recommends the complete destruction of all Ribes* within a distance of 
 200 to 300 yards of native and planted white pines in regions where blister 
 rust is present or within dangerous proximity. This Conference further 
 recommends a vigorous campaign for planting white pine by individuals, 
 corporations, municipalities and state agencies on non-agricultural lands 
 with proper precautions against infection by the blister rust. 
 
 Owing to wide variations in the distance that spores spread from 
 Ribes to pine, due largely to the nature of the vegetation intervening be- 
 tween the Ribes and pine, and to weather conditions, it is impossible to 
 establish a fixed width of Ribes-f ree zone which will be equally applicable 
 to all localities. Therefore, it is the opinion of this Conference, based 
 upon recent investigations that a Ribes-free zone of 200 to 300 yards in 
 width will be sufficient to insure the commercial growing of white pine 
 under average conditions. It is also recommended that white pine should 
 not be planted in the locality of large plantations of Ribes, especially 
 cultivated black currants. This Conference urges that where white pine 
 is to be planted or protected from blister rust, that federal or state agents 
 who are qualified to judge conditions be called upon to determine the 
 width of the zone necessary to protect the pine before the eradication is 
 begun. 
 
 Be it Further Resolved : 
 
 That the planting of Ribes be discouraged in pine growing districts 
 and that the policy of segregating pine growing and currant growing dis- 
 tricts be defined and enforced by competent authorities. 
 
 That the cultivated black currant is a menace and that legislation be 
 enacted declaring it a nuisance in white pine regions. 
 
 ThaLlhis-Confepence-Fe-afSrnas its position taken at previous meet- 
 ings, that the responsibility for control of the blister rust rest- finally with 
 the forest owner; but, in order to hold the ground already gained, and 
 
 *Note:_ For the sake of brevity and convenience, the botanical rime, Ribesi, ig commonly 
 used to designate all species of currants and gooseberries, both the wild and cultivated bushes. 
 
not to lose the benefits of the excellent work already accomplished in 
 many places, we recommend that Federal, State, Provincial and other 
 public appropriations for experimental, demonstration, control, and eradi- 
 cation work in the Eastern States and Provinces, be continued, notwith- 
 standing post-war conditions. 
 
 That, in the Western States and Provinces, the Conference notes 
 with satisfaction that continued scouting has not revealed the presence of 
 the blister rust; the Conference recommends that scouting in these States 
 and Provinces be kept up, and that State and Provincial appropriations be 
 made and Federal appropriations continued to this end. 
 
 That an accurate knowledge of the location and amount of white 
 pine in the country is essential as a basis for our plan of protection. We, 
 therefore, urge that Congress make an appropriation sufficient to cover 
 such a survey ; and suggest that this survey be combined with the survey 
 of pulpwood resources which is being advocated by the Newspaper Pub- 
 lishers Association, and by the American Pulp and Paper Association. 
 
 That a bulletin containing a report of this Conference be published 
 and distributed under a method similar to that used last year. 
 
 That this Conference urges that the American Plant Pest Committee 
 be continued; that it provide a sub-committee on the white pine blister 
 rust ; and that it provide for its future financial support. 
 
 Estimate of Stand of S-Needled White Pines in North Ameeig.^, 
 
 1919.* 
 
 UNITED STATES : 
 
 
 
 
 
 Eastern States 
 Lake States 
 Inland Empire 
 Sugar Pine 
 
 14.5 billion 
 9 
 23 
 38 
 
 ft. at 
 " at 
 " at 
 " at 
 
 $12.00 per M ft. 
 
 15.00 '■ " " 
 
 3.25 " " " 
 
 3.50 " " " 
 
 $174,000,000 
 
 135,000,000 
 
 74,750,000 
 
 133,000,000 
 
 Total 
 CANADA : 
 
 84.5 
 
 
 
 $516,750,000 
 
 Western Canada 
 Eastern Canada 
 
 2.5 " 
 60. 
 
 " at 
 
 " at 
 
 2.00 " " " 
 10.00 " " " 
 
 5,000,000 
 600,000,000 
 
 Total 62.5 $605,000,000 
 
 GRAND TOTAL 
 
 NORTH AMERICA 147 " " at 7.63 " " " $1,121,750,000 
 
 Reported Value of White Pine Lumber F. O. B. Mill.* 
 
 UNITED STATES: (1918): 
 
 (Eastern) White Pine 1,672,383 M ft. at $30.59 per M ft 
 wroctot-n wrhi+a Vina 974. ^ni; •• •■ o+ •ji nv " " " 
 
 Western White Pine 274,605 
 Sugar Pine 111,800 " 
 
 Total, U. S. 2,058,788 " 
 CANADA (1917) 
 
 (Eastern) White Pine 771,119 " 
 
 Western White Pine 20,473 " 
 
 Total, Canada 791,592 " 
 
 GRAND TOTAL 
 NORTH AMERICA 2,850,380 " 
 
 * " Data for United States furnished by tlie U. S 
 ' Chief Forester, Canadian Conservation Commission. 
 white pine stands are based on inadequate data, but 
 .ing information." 
 
 5 
 
 at 
 at 
 
 31.07 
 28.26 
 
 at 24.09 " " " 
 at 20.45 " " " 
 
 at 28.71 
 
 $51,158,793 
 8,531,352 
 3,159,468 
 
 $62,849,613 
 
 18,578,718 
 418,710 
 
 $18,997,428 
 
 $81,847,(M1 
 
 Forest Service, and for Canada by Mr. Clyde Lea vitt, 
 . Except for western Canada, the figures given for 
 epresent the best approximation possible from exist- 
 
SUMMARY BY STATES AND REGIONS 
 
 Compiled by Samuel B. Detwiler 
 
 Maine. Work was done during the season on control areas at 
 Brunswick, Alfred, and Kittery Point. A reduction in cost was achieved 
 through advance scouting to locate wild currants and gooseberries. A 
 man thoroughly acquainted with the growth and habits of these plants 
 went over the control areas ahead of the crews and located the places 
 where wild currant and gooseberry bushes were sufficiently numerous to 
 make it economical to have crews do the work. In the rest of the control 
 area, the scout pulled the bushes as he found them, leaving the areas free 
 from Ribes. Advance scouting is practical only when Ribes grow more 
 or less in colonies, or in certain definite places. 
 
 More than 50,000 acres were mapped to determine the exact location 
 and character^ the white pine growth in order to advise owners on the 
 best means of protecting the pine from blister rust. On 46,000 acres in 
 the towns of York and Kittery, 4458 acres of pure and mixed pine was 
 estimated to have a value of $669,504. The owner of white pine should 
 protect it from the blister rust, just as he protects his timberland from 
 fire. The Forest Commissioner at Augusta stands ready to plan coopera- 
 tive blister rust control work with any organization or individual. 
 
 New Hampshire. In 1919, 53 towns appropriated $8,514.25 to 
 cooperate in blister rust control. In addition, 34 persons, firms, and asso- 
 ciations contributed $2,053.65. Control work was carried on in 49 towns 
 and the entire area of three towns was cleared of Ribes. 
 
 It was possible to make a decided increase over the work done in 
 1918, by improved field methods and more intensive training of the field 
 force. Approximately 2,000,000 currant and gooseberry bushes were 
 destroyed on 163,413 acres, at an average cost of 20 cents per acre, a 
 decrease of 19 cents per acre over the cost of 1918. 
 
 Extensive areas of severely infected pines exist in New Hamp- 
 shire. In a 41 -acre pine lot at Littleton, containing a total of 5442 
 white pines averaging 6 inches in diameter, 3014 or 55 per cent of the 
 trees are infected with the rust. This infection is entirely due to wild 
 gooseberries, which average 30 bushes per acre. The 'oldest infection 
 found on pine in this region is estimated to have started in 1906, or 
 13 years ago. Strip surveys a rod wide, totaling 22^^ miles in length, 
 recently were run out north, south, east, west and southwest from this 
 pine lot across the surrounding country. Out of 2896 pine trees growing 
 on these strips, 25.5 per cent have been attacked by the disease. In addi- 
 tion, 1461 pines were inspected in 33 widely scattered quarter-acre plots, 
 and 41 per cent were found infected. Thus, in an area 8 miles wide and 
 9 miles long, a total of 9,799 pines were examined and 4,359 trees, or 44 
 per cent, found diseased. Since the strip lines give a fair average, it 
 appears that at least one-fourth of the pines in 72 square miles covered 
 by the survey in the Littleton region are infected with blister rust. On 
 another strip line 30% miles long, run from Lisbon to Woodsville and 
 Piermont, 2.4 per cent of 6,758 trees were diseased. This shows that infec- 
 tion is progressing rapidly, and that pine owners should lose no time in 
 
destroying currant and gooseberry bushes in the vicinity of their pines. 
 
 A pine survey made in Dover and Kensington shows that out of a 
 total area of 24,153 acres, there are 6,578 acres of pure and mixed pine 
 estimated to have a total value of $313,358. The State Forestry Depart- 
 ment, at Concord, cooperates with pine owners, towns, and associations 
 in controlling blister rust, so far as appropriations permit. 
 
 Vermont. It is estimated that approximately 25 per cent of the 
 native pine in the towns of Ryegate, Barnett, and Waterf ord are infected 
 with blister rust. Infections were also found in native pines at>Newbury, 
 Fair Haven, Hubbardton, and Bristol, and in pine plantations at Lyndon, 
 Enosburg, Plainfield, Orange, and Cabot. Infections on currants and 
 gooseberries indicate a general scattering of the disease over the State. 
 
 Experimental eradication of currants and gooseberries was continued 
 in 1919 on areas at Sharon, Ryegate, and Fairlee. Mapping of the white 
 pine area has been started to aid in formulating a policy for control of 
 the disease. Pine owners who wish to protect their pine will be given 
 the services of a trained man from the State Forestry Department, at 
 Montpelier, to oversee the work of uprooting currants and gooseberries. 
 Massachusetts. Blister rust has been found distributed through- 
 out the State. Control work was carried on in Templeton, Gardner, 
 Westminister, Ashburnham, Hubbardston, North Andover, Petersham, 
 and Marshfield. In the three latter towns large control areas were worked. 
 Intensive scouting this season revealed that no pine infection had taken 
 place at Lenox and Ipswich after the Ribes were destroyed in 1916. 
 
 Three cooperators subscribed $1075 for cooperative work, and the 
 State Forestry Department cooperated to the extent of $500 in removing 
 Ribes from the vicinity of state plantations. The State Department of 
 Agriculture, 136 State House, Boston, offers advice and cooperation to 
 pine owners who desire to protect their stands from the blister rust. 
 
 Rhode Island. It is estimated that 11,000 acres of young pine 
 and 11,000,000 feet B. M. of merchantable pine were protected in the area 
 from which Ribes were eradicated in 1919, the total value being $300,000. 
 During the past season the cost of eradicating currants and gooseberries 
 was 11 cents per acre, compared with a cost of 27 cents in 1918. This 
 reduction in cost was due to the use of the advance scouting method 
 of locating wild Ribes. The state supervisor laid off 65 check plots in 
 advance of the crews and without their knowledge. The crews found 
 and destroyed 2566 Ribes and. overlooked 113 bushes; an efficiency of 96 
 per cent. 
 
 The annual height growth of 836 wild gooseberries averaged 5 inches 
 for four years. Gooseberry bushes in exposed sites on fairly dry soil 
 averaged 3 inches growth per year. Bushes in moist sites with about an 
 equal amount of sun and shade grew 5 to 6 inches per year. Such bushes 
 did not bear fruit until they were 6 to 8 years old. Gooseberries growing 
 in very dense, shaded sites grew 7 to 8 inches per year during the first 
 three years. No bushes were found in such a site that were over four 
 years old ; they appear to be either shaded out or winter killed. 
 
The State Board of Agriculture, at Providence, will assist pine owners 
 in blister rust control projects. 
 
 Connecticut. The only eradication area consisted of 2500 acres 
 located in the towns of Colebrook and Norfolk where Ribes eradication 
 had been carried on in previous years. Six plantations where rust had 
 been found on pine previously were inspected in 1919. They were located 
 in Litchfield, Groton, Greenwich, and Middlebury. 
 
 In Pomfret where an infection was found on pine in 1917, a small 
 area was cruised to get rid of some escaped Ribes. In order to observe 
 the spread of the disease from the pine infection center, a block of about 
 30 square miles was very carefully scouted and the location of all Ribes 
 was mapped. Another area of about 30 square miles, similar to the one 
 in Pomfret and for the same purpose, was laid off in Branford in 1918. 
 This was carefully rechecked this year. 
 
 The State Agricultural Experiment Station, at New Haven, gives 
 assistance and advice to pine owners relative to blister rust control. 
 
 New York. The blister rust is generally distributed throughout 
 the Adirondack region. There are a number of areas of badly infected 
 pine. Outside this area of general infection, the disease was found on 
 currant and gooseberry bushes in 14 counties. 
 
 One of the outstanding features of the year's work was the favorable 
 attitude of pine owners as shown by the extent to which they cooperated 
 with the Conservation Commission in protecting their property. In addi- 
 tion, several owners removed the Ribes from their land and bore the 
 entire expense. Another feature was the steady improvement made in 
 Ribes eradication. Checking proved that good crews leave only the small- 
 est and least dangerous bushes, and that on areas worked the previous year, 
 less than 10% of the original number of bushes remained. Ribes leaf 
 counts show that when 87% of the bushes are removed, 97% of the leaf 
 surface is destroyed. The leaves of 2194 bushes were counted in this test. 
 In the first working, bushes bearing 94,429 leaves were destroyed. In 
 three subsequent workings only 3094 leaves were found. 
 
 Control work began May 1 and continued six months. During this 
 period over 400 laborers were employed. They removed a total of 
 2,181,286 wild Ribes from 23,194 acres in 22 separate areas. Most of 
 the areas worked this year were unusually rough and difficult territory. 
 The advance scouting method was not employed. Of the total acreage 
 protected, 14,807 acres were privately owned lands on which individual 
 owners or associations have actively cooperated in controlling the disease 
 by paying one-fourth the cost of the work. Advice on blister rust control 
 methods and cooperation may be obtained from the Conservation Com- 
 mission, at Albany. 
 
 New Jersey. General and intensive scouting throughout the 
 State resulted in the finding of one patch of diseased black currants near 
 Red Bank. All of the bushes were destroyed. No diseased pines were 
 found. 
 
In Pennsylvania, Maryland, Virginia, and West Virginia, 
 
 blister scouting was restricted to suspicious pine plantations, cultivated 
 Ribes in their vicinity, and to a general survey of such sections of these 
 states as seemed most likely to harbor the disease. No blister rust was 
 found, although many thousands of pines and Ribes were inspected. The 
 relative scarcity of the host plants in Pennsylvania and New Jersey will aid 
 materially in delaying the spread of the disease southward. 
 
 Minnesota and Wisconsin. In these states, the blister rust is so 
 widespread that it is beyond hope of general eradication. The, area of 
 general infection is approximately 150 miles long by 100 miles wide, ex- 
 tending from the latitude of St. Paul to a few miles north of Duluth and 
 on both sides of the St. Croix River for a width of from one to two 
 counties. Scattered infections were found also in southeastern Minnesota, 
 and an isolated infection in eastern Wisconsin, reported last year, again 
 appeared. 
 
 Pine eradication near Rice Lake, Grantsburg, and Lewis, Wisconsin, 
 in March and April, was successful in checking the spread of the rust and 
 this phase of the work will be continued for the present. The only new 
 serious pine infection center discovered in Wisconsin is in northeastern 
 St. Croix county and all white pine in the heavily infected area are being 
 taken out. 
 
 Ribes eradication was carried on at Rush Lake, Taylors Falls, Grass- 
 ton and Dalbo, Minnesota, over an area of 2,440 acres, and 156,304 wild 
 currants and gooseberries were destroyed. 
 
 The policy of stimulating local control of the disease by cooperative 
 eradication of Ribes around valuable white pine stands has been agreed 
 upon. Ribes eradication will be started first on State lands. Advice and 
 cooperation in blister rust control may be obtained in Minnesota by con- 
 sulting the State Entomologist, University Farm, St. Paul; and in Wis- 
 consin by applying to the State Entomologist at Madison. 
 
 Michigan. The rust was found at Birmingham, Oakland County, 
 on one tree from a local nursery. Though the disease has appeared in the 
 past at three other places in the county, there was no recurrence at any of 
 these places. 
 
 Other States in Central West. Blister rust scouting was carried 
 on in 13 other states, but no signs of the rust were discovered. Two 
 violations of the Federal quarantine were found in Oklahoma, shipments 
 of gooseberries being received by one nursery from Alabama and by 
 another nursery from Iowa. A single violation of this quarantine was 
 also found in Nebraska, where a nursery had purchased 1,000 pines from 
 an Illinois nursery. These violations have been reported to the Federal 
 Horticultural Board. 
 
 Rocky Mountain and Pacific Coast Regions. White pine blis- 
 ter rust has not been found in the Far West. Scouting for the disease 
 began in 1917. The work has been aimed toward (1) locating and 
 inspecting every blister rust host plant that has entered this territory from 
 a region where the disease was present; (2) searching for violations of 
 
 9 
 
the Federal quarantine against shipping 5-leaved pines, currants and 
 gooseberries west of the Great Plains; and (3) general scouting for the 
 disease. During the past three seasons, about 7,000 imported white pines 
 and several hundred thousand imported currant and gooseberry plants have 
 been inspected. Limited scouting for the disease on wild plants has been 
 done in each western state. A Cronartium found on Ribes in Utah, Colo- 
 rado, Nevada, California, Arizona and New Mexico has been identified 
 as C. occidentale, the alternate stage of a peridermium occurring on the 
 pinyon pines. This rust is harmless to white pines. 
 
 Sixty-five species of Ribes are indigenous to western North America. 
 Out 'of thisjgrge^ numb er can be found species ada pted to~nearly" "every 
 sSe^n3lHQllJiCClUlingJIljhesej;egi^^ Thg rnnstant nrnirrenrp nf t hpsp 
 !KbeslHO.uld--affoid,unbroken_chains_£or_^th_e_ d^ white, pine 
 
 blister rust. 
 
 If the sugar pine and western white pine are to be kept free from 
 this disease, five-leaved pines, and currant and gooseberry plants from 
 infected regions must be kept out of the West, as provided by quarantines 
 in both the United States and Canada. Several violations of the Federal 
 quarantine have been discovered in the Rocky Mountain States. A single 
 diseased shipment of either pine or Ribes may result in enormous losses 
 in the Far West, both to private and government holdings. 
 
 Summary of Ribes Er.\dication Data 
 North Eastern States, 1919 
 
 Labor 
 
 Cost per 
 
 Acre 
 
 $0.48 
 .21 
 .93 
 .71 
 .11 
 .93 
 2.19 
 .42 
 
 Scientific Research in 1919 
 
 Conducted by the Office of Investigations in Forest Pathology 
 Bv Dr. Perley Spauldinp 
 
 The investigations of 1919 were carried out in a manner similar to those of 
 the previous year, being conducted principally at North Conway, N. H., and Lewis, 
 N. Y. At the former place, Professor H. H. York of Brown University had direct 
 charge of the work, and at the latter, Professor L. H. Pennington, who represented 
 the State College of Forestry of Syracuse University, a cooperating institution. 
 Special efforts were made this season to determine the distance of distribution of 
 the different forms of spores of the blister rust. 
 
 Professor York, in New Hampshire, found that the ^eciosoores m av apparentl y 
 be_blo wn for a distance of 15 or 20 .r n'lps, and hp rarrip^^ mTa£^l_^rMiii ^gt y, j 
 r etam viability. Viable aeciospores were collected upon the summits ofMoat Mt. 
 -t:j;2U0 feet), Carter Dome (4,800 feet), and Mt. Carrigan (4,700 feet). It appeared 
 that these^sjiores, in some cases must have been blown across the Presidential Range, 
 itnlicatmg that mountain ranges ar£. not an obstacle to the spread of this disease. 
 Viable urediniosBor^sTBLere caughtJii-.traps-3.,2Q0--feet- from their sources, of origin, 
 while_similar_ spores caught at a di5tance_of-3,400 feet failed to germinate. Under 
 
 10 
 
 
 Acres 
 
 Total No. 
 
 No. of 
 
 STATES 
 
 Geared 
 
 of Ribes 
 
 Ribes 
 
 
 of Ribes 
 
 Pulled 
 
 per Acre 
 
 Maine 
 
 9,216 
 
 333,775 
 
 36.2 
 
 New Hampshire 
 
 163,414 
 
 1,681,090 
 
 10.2 
 
 Vermont 
 
 2,460 
 
 96,749 
 
 39.3 
 
 Massachusetts 
 
 10,849 
 
 204,196 
 
 18.8 
 
 Rhode Island 
 
 40,481 
 
 46,197 
 
 1.1 
 
 Connecticut 
 
 2,500 
 
 31,000 
 
 12.4 
 
 New York 
 
 23,194 
 
 2,181,286 
 
 94.0 
 
 Totals 
 
 252.114 
 
 4,574.293 
 
 18.1 
 
a heavy coyerof black alder, viable sporidia produced on skunk currant were caught 
 only up to a distance of 75 feet. None were caught in traps directly over the plants 
 but above the screen of shrubbery. Viable sporidia from cultivated black currants 
 were caught in traps 600 feet distant in an open meadow. Sporidia were caught in 
 traps 2,400 feet from their source of origin but failed to germinate. The sporidia 
 which germinated were' caught during a period of high humidity, while those caught 
 at 2,400 feet, but which did not germinate, were caught on a clear windy day. 
 Tests of the longevity of the sporidia showed that they remained viable for a period 
 of less than ten minutes where the humidity was 90 and the temperature 22 to 2S 
 degrees C. Profe ssor York concluded f rom theserwultSj. that the character of the 
 vegetation intervening between th_e,.Il!E£s anHTpines, an3" ffie crima'fic"co"nd itions are 
 vita l - f ac t o i 's-in the 'dtstance. that sgoridja may communicate tKejiiseaseT 
 
 Professor Pennin'gion,' working"ihlhe Adirondacks, used "spoifeTiraps for deter- 
 mining the distance of distribution of spores, but also had a chance to make studies 
 of the actual distance that infection had spread in pines from Ribes at various 
 points in the Adirondack, region. Apparently, the general conditions existing in 
 the Adirondack section were not quite as favorable for the distribution of spores as 
 they were in the White Mountain section. Viable sporidia were obtained up to a. 
 distance of 180 feet. Sporidia which did not germinate were caught up to 300 feet 
 from their source. Studies of natural infections in pines in nine different places, 
 and where infection came from definitely located bushes of Ribes cynosbati. rotundi- 
 folium, and glandulosum, showed that serious infection occurred up to less than 
 200 feet from the Ribes. The amount of infection of pines depends upon weather 
 conditions, and may be light in some seasons but very heavy in others. Cool, mo ist 
 situ ations, prote cted from winds, favor infection of pine. Inte rvenng_ _baraei:£j3f 
 vegetetjanlierui'- tC!llim.it..inisstiP-R- In general, it-mayj)e said^ tnat under gi ven 
 cnnHitinns the number of mfections in pine varies..(&eetjy.. K!fKrfEe-amD_unti2tiiife£S 
 leaf surfac e and inversely as the square ofj^he distance fr_omJRibes. 
 
 Investigations on The cuttmg biit~ol~infgcTiohs in~pmes were started in 1917 
 by Posey and Gravatt. Ninety-six infections were thus treated. The majority 
 were located on small branches but a number had run back into the larger branches 
 or main trunk of the tree. The age of the wood infected ranged from S to 14 
 years. The infections were cut out at varying distances from the edge of the 
 visibly discolored bark, ranging from about 1/4" up to 6". Enough time has elapsed 
 since these infections were removed for the disease to reappear at the edges of 
 the cuts if it is going to. In brief, it may be said that where the cut was made 
 at 1 1/2" distant from the visibly affected part, the disease has not again reappeared. 
 
 Investigations of the blister rust have now been carried on for a decade. At 
 first we were in almost total ignorance of the practicable bearings of this disease. 
 Naturally mistakes have been made, largely because we were unable to make per- 
 sonal investigations of the outbreaks in Europe. Damage to old trees results in 
 an unexpected manner, — namely, from infections upon lateral branches running 
 backward into the main trunk. Trees up to one foot in diameter at the point 
 where girdled have thus been infected. _ 
 
 Our studies of the distance of distribution of the various spore forms and of 
 the distance that infection has actually occurred upon pines from known infected 
 Ribes indicate that the Ribes-free-zone should be, under average conditions, 200 
 to 300 yards in width. It should be much more where conditions are exceptionally 
 favorable for transfer of the spores from Ribes to pine, i. e. near large bodies of 
 Ribes where there is no screen of vegetation over the Ribes or between the Ribes 
 and the pines or in exceptionally humid situations. The cultivated black currant, 
 Ribes nigrum, should not be allowed in an infected pine district because of the 
 
 special danger from it. .... . - , .-^ .. t 
 
 The insidious spread of this disease in a given locality cannot be over- 
 emphasized. Over-wintering by means of aeciospores in old cankers on living 
 nines and also by means of urediniospores upon dead infected Ribes leaves has 
 been'oroven Special attention should be given to the fact that quantity of mfec- 
 tion of pines rests to a great extent upon the volume of _ spores produced by the 
 Lfecting currants. In other words, the efficiency of eradication of Ribes depends 
 upon the relative reduction of Ribes leafage, upon which directly depends the 
 quantity of spores given off to infect pines. 
 
 11 
 
Artificial Infection of Pines with Cronartium Ribicola 
 
 Conducted at the Connecticut Experiment Station 
 By Doctors G. P. Clinton and Florence A. McCormick 
 
 This is a report of the results of artificial infection 6i pines along the same 
 lines as was reported a year ago in Bulletin 2 of this committee Successful 
 inoculations have been made on over ISO young pines, somethmg like 10,000 distinct 
 infections having been secured. These experiments show that infection takes place 
 through the stomata of the leaves. The first visible sign of the infection is a 
 minute golden-yellow spot centering over the lines of the stomata on the lower 
 side of the leaf. Under greenhouse conditions these became evident within three 
 months after inoculation. Infection takes place within 48 hours. Leaves up to 
 two years of age have' been abundantly infected. Infection within a leaf is indi- 
 cated by the formation of a peculiar swollen body within the stomatal cavity in 
 the leaf, from which a single hypha runs downward and soon gives rise to relatively 
 large sclerotial bodies. Then the mycelium extends into the vascular bundle of 
 the leaf and follows downward until it reaches the twig. Progress down the leaf 
 and into the twig is apparently quite rapid under conditions favorable to plant 
 growth. Trees of Pinus excelsa, flexilis, koraiensis, cembra, densifiora, austrtaca, 
 resinosa, and syh/estris were inoculated without success. No infections have de- 
 veloped beyond the pycnial stage upon any species except Pinus strobus. Early 
 stages of infection have been secured upon lambertiana and the two pitch pines. 
 pinea and sabiniana. Tests have not yet been made with the pinon pines, P. emits 
 and monophylla. Details of these experiments were largely published in Bulletin 
 214 of the Connecticut Agricultural Experiment Station. 
 
 The Destruction of Ribes by Chemical Means 
 
 By Dr. W. S. Regan 
 
 Three years' study 'of various chemicals for killing currant and gooseberry 
 bushes has been made, to discover a cheaper means of destroying these plants 
 than by hand pulling. Fuel oil and dip oil have given good results. 
 
 r)IP OIL. (Twenty-five per cent cresol; fifty cents per gallon) was used 
 straight or diluted with fuel oil. One treatment of dip oil (straight) applied to 
 the top or crown of bushy species of Ribes kills in the majority of cases. Dilutions 
 with fuel oil of 1 to 5 or 1 to 8 appear most satisfactory for the treatment of 
 skunk currant areas, but two or more treatments are required for a complete kill. 
 
 Dip oil (straight) applied to the tops kills the Ribes foliage in from about 
 half an hour to a few hours, regardless of exposure to sun or shade. Crown treat- 
 ment alone usually kills the plants slowly, often requiring several weeks, or even 
 months. The eificiency of dip oil appears to be little affected by rain, the absence 
 of foliage, or season of application, so long as the treatment is thorough. 
 
 FUEL OIL. (Light grade, 36.3 degrees Beaume, fourteen cents per gallon) 
 gives best results when applied to entire top and crown. One treatment will fre- 
 quently kill bushy species; but often two treatments, rarely three, are required. 
 In the case of areas of skunk currant, three or more treatments will usually be 
 required to obtain a complete kill. Dip oil and fuel oil are not poisonous to animals, 
 and do not injure other vegetation if reasonable care is exercised. Where wild 
 currant and gooseberry bushes are large and numerous, or grow in walls an<} stone 
 piles where hand pulling is difficult, spraying with fuel oil should result in a 
 material saving in cost, although combination with dip oil appears preferable. It 
 does not ^pear to be economical to treat small plants of the bushy species, which 
 are easily pulled by hand. One and three gallon brass compressed-air sprayers 
 are satisfactory for applying the oils. 
 
 12