^\ DETRIMENT (t OF AGRICULTURE BUREAU OF ENTOMOLOGY AMO )! TLAi-JT QUARANTINE SOME NEW OR LITTLE-USED INSECTICIDES WORTHY OF FURTHER TESTING Part I. Copper-Arsenic Compounds]./ By R. C. Roark, Division of Insecticide Investigations The history of several of our most potent and useful insecticides reveals that many years frequently elapse between the first published account of them and their general adoption. For -example, derris was men- tioned as an insecticide in 1848, and a study of its possibilities was reported in 1919, but it was not used in quantity in the United States until 1931. Tartar emetic was tested as an insecticide in 1890, but did not come into large-scale use until about 1936. The writer believes that the time between the initial discovery of the insecticidal action of a material and its commercial adoption could be greatly shortened by proper publicity. When sufficient information on the insecticidal value of a material is published, its commercial production will be eagerly undertaken by the chemical industry and it will be made available for public use. The first step in this plan is to stimulate interest among entomologists so that many tests against different insects will be made. In the present series of papers an effort is made to bring to the attention of entomologists materials not now used commercially as insecticides, but which are believed to possess possibilities for insect control that should be further explored. c Compounds Related to Paris Green Paris green is one of our oldest insecticides and, in spite of competition from the newer arsenicals such as lead arsenate, calcium arse- nate, and zinc arsenite, it is still consumed to the extent of about 2 million pounds annually. It has the formula 3CuAs204.Cu(CH3C00) 2 and contains 58.55 percent of arsenic trioxide, 3] .39 percent of cupric oxide (equivalent to 25.08 percent of copper), and 10. OS percent of acetic acid anhydride. 1/ Free use has been made of unpublished data obtained by E. H. Siegler, of the Division of Fruit Insect Investigations, and M. C. Swingle and associates, of the Division of Control Investigations. Grateful acknowl- edgment is made to these Divisions for permission to use their results. - 2 - Dearborn (1, 2) has prepared compounds analogous to paris green using such acids of the acetic series as formic, propionic, butyric, mono-, di-, and trichloroacetic, lauric, palmitic, stearic, and melissic. These greens are made by adding a hot aqueous solution of a soluble copper salt, such as copper sulfate, to a hot solution of sodium arsenite mixed with a hot solution of an alkali-metal salt of the fatty acid (i.e., a soap) and heating. Unsaturated acids, such as crotonic, oleic, erucic, linoleic, and linolenic, and also mixed acids resulting from the saponification of vege- table or animal oils can be similarly used (3, 4, 5, 6, 7) . Acids from the following oils have also been employed to prepare copper-arsenic compounds: Castor, coconut, cottonseed, corn, linseed, menhaden, palm, peanut, rapeseed, sesame, soybean, and tung. The insecticidal values of these greens have been tested only to a limited extent. Fleming and Baker (12) tested paris green and a number of its homologues in comparison with lead arsenate for the control of the Japanese beetle (Pcpillia japrnica Newm.). Fotted smartweed plants were sprayed with each arsenical in several concentrations and then placed in glass cages under controlled temperature, relative humidity, and light. Freshly collected Japanese beetles that had been starved for 6 hours were distributed in each cage, and after 48 hours a record was made of beetle mortality and spray injury. Their results for a concentration of 8 pounds per 100 gallons are as follows: Material Coefficient of effectiveness Injury to foliage Lead arsenate 1.00 Copper crotonoarsenite 73 Paris green 68 Copper palmitoarsenite 64 Paris green and flour 60 Tung-oil green 56 Cottonseed-oil green 55 Paris green and summer oil 54 Copper lauroarsenite 38 Soybean-oil green 28 Copper stearoarsenite 24 Copper oleoarsenite 24 Flapeseed-oil green 09 Slight Moderate Slight Slight Moderate Slight Moderate Slight Severe Slight Very slight Slight Moderate Fassig and Campbell (11) tested the effectiveness of some of these greens against the confused flour beetle (Tribplium confusum Duv. ) by placing ^oung beetles in a mixture of 10 parts of insecticide and 90 parts of finely milled whole-wheat flour for 24 hours, with the following results: - 3 Series 1 Material Percent mortality Copper stearoarsenite Soybean-oil green Linseed-oil green Fish-oil green Copper oleoarsenite Lead arsenate Series 2 Copper crotonoarsenite Copper lauroarsenite Peanut-oil green Copper n-onochloroacetoarsenite Copper dichloroacetoarsenite Paris green Lead arsenate 88 84 £6 17 7 £8 £2 SI 64 C2 51 11 The greater effectiveness of some of these compounds was attributed in part to tetter adhesiveness and to a possible difference in particle size. Several of these greens were tested in the laboratory by J . B. Gahan and A. M. Phillips, at Sanford, Fla., under the direction of M. C. Swingle, against fourth instars of the southern army worm (Prodenia eridania (Cram.)) and fifth instars of the fall webworm (Ryphantria cunea (Drury)) and the melon- worm (Diaphania hyalinata (L. ) ) . Cooper oleoarsenite and greens prepared from fish oil, tung oil, peanut oil, and linseed oil were effective against the southern armyworm and the melonworm but were ineffective against the fall webworm. No significant and consistent differences between these greens were detected. lowing ville, Ions: Against larvae of the codling moth (Carpocapsa p_cmonella L.) the fol- results were obtained by Dr. Siegler in laboratory tests at Belts- Md., when he used these greens at the rate of 4 pounds per 100 gal- Material Fish-oil green Peanut-oil green Copper oleoarsenite Linseed-oil green Tung-oil green Copper phenylstearoarsenite Percentage of apple plugs Wormy c- J. 1.9 0.0 1.0 5.9 5.7 1.9 9.6 5.8 14.0 3.2 23.6 17.9 Compounds Made with Sulfurized Organic Acids When an unsaturated organic acid, such as oleic, is heated . sulfur at about 200° C, with a little iodine added as a catalyst, 1 atom of sulfur is taken up by each double bond of the acid. Clupanodonic acid from fish oil, which contains 4 double bonds, may theoretically combine with 1, 2, 3, or 4 atoms of sulfur under the same treatment. The resulting sulfurized acids may be combined with copper and arsenic in the same way as the unsulfurized fatty acids (8) . Free fatty acids, obtained by saponifying a vegetable, animal, or fish oil, may be sulfurized and used in this process. Examples are the acids from peanut, linseed, fish, and tung oils (9, 10) . The sulfur in the greens prepared from these sulfurized acids ranges from about 4 to 10 percent, the arsenic trioxide from 36 to 39 percent, and the copper oxide from about 19 to 21 percent. These products are of a dirty green color, have a greasy feel, are insoluble in water, and require the addition of a wetting agent. Swingle and associates found that copper sulfoleoarsenite, containing 29.8 percent of arsenic trioxide, 5.2 percent of sulfur, and 17.8 percent of copper, when applied as a dust was effective against the Australian cock- roach (Periplaneta australasiae (F. ) ) , the banded cucumber beetle (Diabrotica balteata Lee. ) , the cross-striped. cabbage worm (Eyergestis rimesalis (Guen. ) )» and the imported cabbage worm (Pie rig rapae L.), but was ineffective ag< the melonworm, larvae of the Mexican bean beetle ( Ep i 1 a chna_y ar iy es t i s (Muls.)), and the adult squash bug (Anasa tristis (Deg.)), and only partly effective against mosquito (Culex spp.) larvae (73 percent mortality in 18 hours at ICO p.p.m.). When this material was tested by Dr. Siegler against codling moth larvae by the apple plug method at a concentration of 4 pounds per ICO gallons, 7.5 percent of the plugs were wormy and none were stung. Lead arsenate usually gives about 40 percent of wormy and stung apple plugs at the same concentration. Greens mace from sulfurized tung oil, fish oil, and linseed oil, when tested against the same insect, gave 13.9, 15.7, and 18.2 percent of wormy fruit and 1.9, 4.9, and 6.1 percent of stung fruit. Effect of Greens on Apple Foliage Dr. Siegler sparyed greens made from fish, peanut, linseed, and tung oils, and also from sulfurized fish, linseed, and tung oils and copper oleo- arsenite and copper phenylstearoarsenite, upon young Sta^man and Grimes Golden apple trees at Beltsville, Md. The concentration of these sprays was 4 pounds per 1C0 gallons of water. The foliage was injured in every in- stance, and the peanut-oil green defoliated the tree. Whether this tendency to cause serious injury could be overcome by the addition of hydrated lime or other "safener" designed to lessen the effects of soluble arsenicals has not yet been determined. The above greens and also those o rom sulfurized corn, soj.' and peanut oils were tested in .oratory by Swingle and associates 5 - against one or more of the following insects: Banded cucumber beetle, Colorado potato beetle (Leptinotarsa decemli.nea.ta (Say)), cross-striped cabbage worm, imported cabbage worm, melonworm, mosquito larvae, southern arms worm, and southern beet webworm (Pachyzancla bipunctalis (F.)). The mortality was practically 100 percent for all species except mosquito larvae, which exhibited mortalities of 76 to 94 percent following applica- tions of 100 p. p.m. Suggested Uses The foregoing results clearly show that these compounds are very toxic to insect pests. As their physical properties, such as wettability, ad- hesiveness, etc., vary with the type of acid employed (saturated, unsaturated, halogenated, etc.), and also with the arsenic and copper content and the solubility, a series of new insecticides possessing a wide range of physical and chemical properties is available. The following uses for these greens are suggested: (1) The green made from formic acid contains the most arsenic (60.22 percent As203) and should be superior to paris green in insuring a quick kill of cotton flea hoppers, bollworms, boil weevils, cotton leaf worms, Colorado potato beetles, and other insect pests of plants that are resistant to soluble arsenicals. (2) The greens made from oleic or stearic acid or from the fatty acids from peanut, soybean, or other vegetable oils yield but little soluble arsenic when added to water and are worthy of testing as substitutes for lead arsenate for combating certain insects. It will be necessary to add a little wetting agent to these greens because of their greasy character, and also a safener to lessen the effects of soluble arsenic and soluble copper upon the foliage of some plants. If the tendency to injure apple foliage can be overcome, these materials would also be worth testing against the codling moth. (3) The same greens, because they remain floating en water longer, should prove superior to paris green for the control of surface-feeding mosquitoes. (4) These oil greens are wetted by petroleum oils. A product made by grinding one of these greens in a petroleum spray oil and emulsifying in water offers possibilities for the control of insects now combated by lead arsenate-oil sprays. (5) All these greens contain a considerable amount of copper (25.79 percent as a maximum in formic green), which should display the characteristic fungicidal action of this metal. Summary Many coir.pcur.ds analogous to paris green have been prepared by sub- stituting other organic acids for acetic acid. Such acids may be sub- stituted by halogen or other radicals, or, if unsaturated, they may have an atom of sulfur added to each double bond. Methods cf making these compounds, called "greens," have been de Tests made by entomologists with several representatives 'erent classes of these greens have shown the following results: Insect Toxicity unaer .aboratcry conditions Australian cockroach Eanded cucumber beetle Codling moth (larvae) Colorado potato beetle Confused flour beetle Cross-striped cabbage worm Fall webworm Imported cabbage worm Japanese beetle Melonwor.n Mexican bean beetle (larvae! Mosquitoes (larvae) Southern army worm Southern beet webworm Squash bug (adults) Toxic [ Superior to lead arsenate Toxic -rior to load arsenate Toxic oxic Toxic Inferior to lead arsenate Toxic Nontoxic Toxic Toxic Toxic Nontoxic Literature Cited (1) Dearborn, F. E. 19C5. Ho.r.ologs of paris green. I. Lower merrters of the acetic acid series. Jour. Econ. Ent. 23: 710-714. (2) 1936. Koir.ologs of paris green. II. Ki bers of the acetic acid series. Jour. Econ. Ent. 29: 445-449. (3 1937. Koir.ologs of paris green. III. Members of the oleic and linoleic acic series. Jou] Ent. 30:140-143. (4) 192,7 Homologs of pari- . cticides prepared from animal and vegetable oils. Jour. Econ. Ent. 30:958-962. (5) 1937 Double salt of copper arsenite and copper salt of an un- saturated fatty acid and process of making the same. U. S. Patent 2,080,004; issued May 11. - 7 -• (6) Dearborn, F. E. 1938. Double salts of copper arsenite and a copper salt of a higher unsaturated fatty acid. U. S. Patent 2,104,584; issued January 4. (7) 1938. Insecticide and fungicide. U. S. Patent 2,127,380; issued August 16. (8) 1939. Compounds of copper, arsenic, and a sulfir.onocarboxylic acid and process of making them.' U. S. Patent 2,159,585; issued May 23. 19) (10) 1939. Processes of treating glycerides. U. S. Patent 2,169,793; issued August 15. 1940. Insecticide and fungicide. U. S. Patent 2,201,103; issued May 14. (11) Fassig, W. W., and Campbell, F. L. 1937. Relative effectiveness of homologs of paris green against confused flour beetle. (Scientific Note) Jour. Econ. Ent. 30:681-382. (12) Fleming, W. E., and Baker, F. E. 1936. Paris green and its homologues as insecticides against the Japanese beetle. Jour. Agr. Res. 53:187-195. UNIVERSITY OF FLORIDA lllllllllllll 3 1262 09224 7435