A survey for resistance to acaricides in cattle ticks (Acari: Ixodidae) in three major traditional cattle areas in Zambia

A survey for resistance to acaricides in Rhipicephalus appendiculatus Neumann, Amblyomma variegatum (F.), Boophilus decoloratus (Koch) and B. microplus (Canestrini) was carried out in three important cattle areas of Zambia during three consecutive rainy seasons (November-May) from 1981-82 to 1983-84 to determine the pattern and distribution of resistance to dieldrin, dimethoate, dioxathion and chlorfenvinphos. Resistance was assessed using the FAO resistance test kit. Resistance to dieldrin, dimethoate and dioxathion was found in a greater number of samples from Central and Southern Provinces than from Northern and Eastern Provinces. Relatively high resistance factors were recorded for R. appendiculatus against dimethoate (mean resistance factor (RF) 10.7 ¦ 3.8 x) and dioxathion (mean RF 8.6 ¦ 1.9 x). B. decoloratus from Central and Southern Provinces showed mixed responses to dieldrin and low resistance to dimethoate (mean RF 4.1 ¦ 2.3 x) and dioxathion (6.4 ¦ 5.0 x). Most samples of A. variegatum and B. microplus were susceptible to the four acaricides. Generally, most of the ticks tested showed high susceptibility to chlorfenvinphos