Control of tick (Acari: Ixodidae) infestation by application of ear tags impregnated with acaricides to cattle in Africa

Nine types of plastic ear tags impregnated with organophosphorus, amidine or synthetic pyretroid compounds were applied to both ears of groups of five Maasai zebu cattle in Narok District, Kenya, and grazed together with five untagged cattle to which no acaricides were applied. Most of the tag types gave highly efficient control of Rhipicephalus appendiculatus Neumann attaching to the head and ears of the cattle, which lasted up to 160 days after application and often completely prevented tick engorgement. All the chemical groups were effective. The most effective tag was a combination of amitraz and permethrin which gave better control than either chemical on its own. Control of Boophilus decoloratus (Koch), Amblyomma cohaerens Dönitz, A. variegatum (F.) and R. evertsi evertsi Neumann attaching to the bodies of cattle was less effective, although most of the tags exerted some effect. Rainfall appeared to reduce the degree of control by the tags. A role for such impregnated ear tags for the control of cattle ticks in Africa is suggested