February 1945 B-633 UNITED STATES DEPARTM/MT OF AGRICULTURE Agricultural Research Administration Bureau of Entomology and Plant Quarantine A NEW REMEDY FOR FLEECE WORMS By C. S. Rude, C. L. Smith, and H. E. Parish, Division of Insects Affecting Man and Animals The true fleece worm, or wool maggot, is the larva of the "blowfly Phormia reglna (Meig.). Several other species at times initiate similar attacks on sheet) and goats. In this re-oort the term "fleece worm" has "been expanded to include Cochliomyia macellaria (F.) # The fleece worms are among the most important "blowflies attack- ing sheep, not only in the Western States, hut also in many other parts of the world where sheen are produced extensively. They rank next to the screvworm ( Cochliomyia americana C. and P.) in infesting wounds of animals. However, the greatest injury is caused "by their attacking the soiled wool, particularly before shearing in the spring, when the animals are carrying a heavy fleece and are inclined to scour. Sheep infested with fleece worms have a tendency to "fever" ouickly, and unless animals receive -orcnrDt attention, they will not survive. This condition is due in part to the rabidity with which the fleece worm infestation spreads over the animal. To prevent infestation of their animals, especially of ewes at lambing time, most sheepmen practice "crutching" or "tegtfing, " which consists of shearing the wool from the crutch late in the winter shortly before lambing begins and before green grass and weeds become abundant. In spite of benefits gained by this practice many sheep become infested with fleece worms. This is particularly true when considerable rainfall occurs 1n the <=r^rir>^ and when the weather in general is cloudy, warm, and humid. Such weather prevents the wool from drying and thereby makes is more attractive to the flies for egg deposition. Various materials have been used for treating animals infested with fleece worms. In the case of sheet) it has been necessary to shear the infested area prior to treating, which is an expensive and dieagreeable task. Research by the Bureau of Entomologv end Plant Quarantine has developed a. remedy which may be anplied without shearing the infested areas. A preliminary reoort on this work was published by Knipling in I9U? \J , This remedy ^enetratps the wool and kills the larvae as it cones in contact with them, and at the same tine coats 1/ Knipling, E. F. A preliminary renort on a treatment for fie >ce worm-infeptations in sheep. Jour. Fcon. Ent. 15: BQ6- 19^2. - 2 - UNIVERSITY OF FLORIDA lllllllllllll 3 1262 09230 3790 the wool and skin to give protection against subsequent reinfestation. In developing this remedy a number of protective chemicals were tested which gave almost equally good results, but the one selected was chosen on the basis of safety, availability, and price, as well as effectiveness. The remedy consists of a proper mixture of benzene as a killer, diphenyl as a protective chemical, Triton 770 (sodium salt of an alkylphenoxypoly ether sulfate) as a wetting agent, and n-butyl alcohol as a combining egent. Preparation of the Remedy The remedy is known as Formula M. S. 793 F t and is composed of the following ingredients (proportions are by weight): Diphenyl, 10 parts; benzene, £h parts; Triton 770, 1 part; n-butyl alcohol, 5 part 8. The diphenyl should be dissolved in the benzene, preferably by allowing the two substances to stand together in a closed con- tainer. Shaking the container will hasten the procedure. In no event should the mixture be heated over, or brought near, an open flame, as benzene is highly inflammable. The Triton 770 and the n-butyl alcohol should be mixed together, then added to the mixture of benzene and diphenyl, and thoroughly agitated by shaking. When first made the mixture will have a cloudy arroearance, which will disappear on standing. The finished product is clear and almost colorless. Use of the Remedy In treating a sheep infested with fleece worms the extent of the infested area should first be determined. Sufficient of the remedy should then be poured onto the area to wet the wool, not only in the infested area but also for about 2 inches beyond. It is best to treat the outer portion of the infested area first to prevent worms from crawling into the uninfested wool. It is not necessary to rub or otherwise work the mixture in, as it penetrates the wool readily. The linuid may "be poured from a bottle or small-mouthed can. Whatever container is used, it should be of a type that can be tightly closed when not in use. Arroroximately a pint of the liotiid is needed to treat the average case of fleece worms. However, if care is taken to wet thoroughly the infested area and the bordering region, a single applica- tion is usually sufficient to effect a cure. Additional applications of the remedy should be made whenever the wound becomes reinfested. Formula M. S. 79^F is safe to use on livestock, since it has been tested on several hundred sheep with no ill effects. It kills fleece worms quickly and provides satisfactory protection from reinfestation. Moreover, wounds treated with this remedy heal quickly.