Circular N United States Department et Agriculture, BUREAU OF ENTOMOLOGY L. O. HOWARD. Entomologist and Chief of Bureau. THE ALFALFA a ILL IIDGE. • I tphondylla miki Waciitl, i By r. M. \\ i BS1 i n. In clan * •;/ urn} Foragi Insert Investigation*. I STBODl i TION. The object in publishing ;i circular mi the alfalfa gall mi« I^r«* (Asphondylui miki Wachtl) at the present time is to direct the atten- tion, especially of alfalfa growers in the southwest era portion of the country, t<> the appearance of this foreign insect in the United States, with the hope thai they will be led to observe the galled pods shown in figures 1. 2, ;m :inf the same to this bureau. \- a matter of fact, we do not knew and ean not foresee what injuries thi- insect will cause in this itry, though it has not so fai proved destructive. We do not m i-h M cause any 1 1 mint* apprehension relative to its effects, but feel that we ought to bring it- presence in alfalfa fields te the attention of farmers, w that it may be earefnlly watched. It has n«>t. therefore, been thought necessary to publish here ;i full technical description of tin- midge beyond what i- shown in the illustration (fig. 1). Galls, from which this insect was afterwards reared, were first found in limin>. Smyth, of this hureau. in ahout the same 76"— Clr. 147— U* I'l.;. 1. A hpnel of alfalfa with all of Hi. I by t ho nl- f:ilfn irnll inlilc h u n ,1 ]i 1 i uppermost which htly nf- Sllchtly enlarged. (Orig- inal.) THE ALl'ALFA GALL MIDGE. numbers as previously observed by him at Sacaton, May 27, 1911. In sending a lot of heads of alfalfa from Tularosa, N. Mex., July 13, 1911, Mr. M. A. Bishop, a farmer, directed our attention to reports among his neighbors of injury to the seed and complaints of bee keepers of a lack of honey in the bloom. A considerable number of these galled pods was included in his sending, apparently without having been ob- served by him. DESCRIPTION or Till: CALL. The following is a translation of the original dascription of the gall (fig. 3) found in alfalfa fields in the vicinity of Vienna, Austria: The formation of the gall stands out as a deformation of the seed-pod of the lucerne. Medicago sativa L. The deformed pod does not show the same snail coil shape as in the normal, healthy condition, but it is shortened at the point, where it is somewhat shrunken. It is strongly bloated up and swelled out, particularly in the proximity of the base, the valves of the pod are considerably thicker, and the rest of it is flesh-like in color. Although the pods keep the green color on the outside, they contain no seed. It is not impossible that the insect, by visiting in large numbers fields containing lucerne, might injure the seed harvest of this clover species quite considerably. The pupa bores through the wall of this pod with the intention of transforming to the imago. It is then situated laterally and below the shrunken gall point. On Medicago falcata L. I have found exactly the same gall formation, but only a few examples. Although I did not take the flies out of these galls, I do believe, never- theless, that these galls in their formative condition agree exactly with those of the preceding species, and since one out of the same conspicuous pupal cases belongs to an Asphondylia, I dare to conclude therefrom that their origin may be traced to Asphondylia miki.* The description of the gall forms on both species of Medicago are taken from Donau-Auen of Wien. From the galled seed pods found by him at Sacaton, Mr. Ainslie was able to rear the adult insects (fig. 4), which were later deter- mined by the late Mr. D. TV. Coquillett as Asphon-dyVia, mdlci, as 1 (J. IMtter v. Frauenfeld had already become acquainted with this gall formation for in the Verb, d. k. k. zool.-hotan. Ges., Jahrg. 1861, Bd. XL p. 17.°.. ho says: "The Oall flies inhabit the flowers of the Medicago sativa L. in large numbers, and the fruit of Medicago in even greater numbers." [KaiBerlich-kSnigliche Zool.-bot. Ges. in Wien., vol. 30, p. 035, 2 tab. XVIII. tig. 2, 1880.] Fig. 2. — A head of al- falfa with the seed pods uninjured ex- cepting the lower one at right, which has been attacked by the alfalfa gall midge. Slightly en- larged. (Original.) Fig. 3. — A single seed pod of alfalfa de- stroyed by the alfalfa gall midge. Much en- larged. .(Original.) I'll I \l.r \l.l \ UALL \l 1 1 m ; i described in 1880 from the vicinity of Vienna* Austria, where the species appears to affed alfalfa in precisely the same way as in Arizona and New Mexico. I III \D\ I l M ll'i.i . "^ / / This midge belongs w ith :i group of flies w hich in- cludes tlic wheal midge \i ohtarinia tritici Kirby), the clover midge ( l><>s>i- )u ura h guminicola Lintn.), and the sorghum midge ■ a fa /-in in 8orgh 1 1 a J n .). The insects are very small and obscurely colored, 90 that the fanner will hardly ho likely to observe them. He will. however, have no difficulty in detecting the galled 9eed pods. During the last year or two a Dumber of complaints have been re- ceived from the Southwest relative to the failure of alfalfa seed to develop. This has been attributed by farmers i<> a number of insects, hoik- of which i- al all likely to 1.,. responsible for the injury, while it is quite possible that it may he due to this gall midge. 1111: i-i r \. The pupa is shown in figure •">. The dor- sum, or hack, i- illustrated in figure •">. ./. which shows the -pine- that enable it to work it> way through the wall- of the galled pod, a- described in the preceding translation. 1 ill.- ni falfn gall midge: Adult female, with antenna of male above, al left. Greatly enlai - n;ll . Pi ■ •" The alfalfa gall midge: «7. Papa, dorsal v law, showing the spines : !h> back, by the aid of arnica it works Itself oul of tba galled pod : b, van tral or under side of OreaUj enlarged. 1 '^rlidnnl i 11 w.i 1 - OF nil 1 \-i 1 1. We hive not. up to the present time, been able to secure very much definite information relative to the pest From the notes made by Mr. A in-lie and also by Mr. Smyth, it would appear that the insect winter- in the pod-. So tar as i- now known it- breeding season during summer i- rather short, a- it ha- not been noticed earlier than late May or later than September, excepting that Mr. Aim-lie reared adults, in confinement, UNIVERSITY OF FLORIDA THE ALFALFA GALL M ~. 3 1262 09216 5660 as late as October 26. This late date would indicate an emergence in .spring, rather than in late fall, under natural conditions. OBSCURITY SURROUNDING ITS APPEARANCE. That the insect should first make its appearance in the midst of a desert country (see fig. (5) is somewhat surprising. There is nothing known of it that would lead us to believe that it can l>e distributed in alfalfa seed. It could hardly have been imported accidentally from the Eastern Hemisphere into this part of the country. Besides this, it is preyed upon extensively by parasitic insects, which would imply a rather long residence in this country, although as these parasites are all new to science and have never been described, it would almost seem that it might be working it- way from Mexico northward. The abund of these parasites is an encouraging feature, at they tend to prevent its becoming destructive. "With the additional information which we hope to obtain, both from investigations of the bureau and from those into whose hands this circular may fall, we shall probably be able to dispel much of the obscurity at present sur- rounding the pest. The indications are that it is spreading over the alfalfa-growing sections of the extreme Southwest, but it does not neces- sarily follow from this that it will prow destructive as have many other insects coming to us from across the Atlantic Ocean. PREVENTIVE MEASURES. It is yet too early to say much concerning measures for preventing injury by the alfalfa gall midge. Of course, mowing the alfalfa j as the plants are coming into bloom will doubtless keep the numbers ci' the midge much reduced, as this method tends to prevent develop- ment, and. therefore, to curtail increase in numbers. A significant observation made at Sacaton. Ariz.. May 27. 1011. by Mr. Smyth, is quite suggestive. "The galls were found very sparingly in fields which had been cut for hay less than two months since, and in such fields from none of the galls had the adults issued. But in one field of both purple and yellow flowering alfalfa, which had not been from early spring at any time cut for hay. but rather allowed to run to seed, the galls were far more plentiful than in other field-, and from a large percentage of them adults, or parasites, had issued." A}jp roved : James Wilson, Secretary of Agriculture. Washington. D. C.. January '/. 1912. O Fig. 6. — Map showing localities where 1 lie alfalfa gall midge has been found in the United States. (Orig- inal, i