A Preliminary Report on a Treatment for Fleece-worm Infestations in Sheep1

Abstract

Benzene combined with 15% of diphenylamine, diphenylene oxide, or p-nitrophenetole with or without a setting agent (10%) applied on artificially induced fleece-worm (Phormia regina, or mixed cultures of P. regina, Cochliomyia macellaria, and Lucilia spp.) infestations gave effective control; only 1 of 155 sheep became reinfested following treatment. Benzene without added materials was ineffective; 34 of 44 sheep so treated became reinfested in 1-3 days. 15 natural infestations were treated with benzene plus either diphenylamine or diphenylene oxide and no reinfestations occurred. Since diphenylamine is used for screw worm control, it is considered more practical than diphenylene oxide or p-nitrophenetole. Addition of a wetting agent may be advantageous but is questionable because of increased cost. Shearing of wool from infested area prior to treatment is recommended. Treatments tested are believed to have prevented reinfestation by repellent action, ovicidal action against eggs deposited after treatment, and killing larvae that may hatch from such eggs as are deposited.