Resistance status of ticks (Acari; Ixodidae) to amitraz and cypermethrin acaricides in Isoka District, Zambia
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Date
2015-08
Authors
Muyobela, Jackson
Nkunika, Phillip Obed Yobe
Mwase, Enala Tembo
Journal Title
Journal ISSN
Volume Title
Publisher
University of Zambia
Abstract
This study was designed to obtain data on the
farmer’s approach to tick control and to determine whether
Rhipicephalus appendiculatus Neuman, Amblyomma
variegatum (Fabricius), and Rhipicephalus (Boophilus)
microplus (Canestrini) were resistant to amitraz and
cypermethrin acaricides, in Isoka District, Zambia. Prevailing
tick control practices were documented by administering a
semi-structured questionnaire to 80 randomly selected smallholder
livestock farmers from four agricultural camps (Longwe,
Kantenshya, Kapililonga, and Ndeke) in Isoka District. Modified
larval packet test (LPT) bioassay experiments were used to
determine the resistance status of the common tick species
against amitraz and cypermethrin acaricides. Fifty percent of
respondents practiced chemical tick control with amitraz
(27 %) and cypermethrin (23 %) being the acaricides in use,
and were applied with knapsack sprayers. Less than 3 l of spray
wash per animal was used which was considerably lower than
the recommended delivery rate of 10 l of spray wash per animal.
No significant susceptibility change to amitraz at 95 %
confidence level was observed in R. appendiculatus and
A. variegatum against amitraz. However, a significant change
in the susceptibility of R. (Bo.) microplus tested with amitraz
was detected at 95 % confidence. The test population had a
lower susceptibility (LD50 0.014 %; LD90 0.023 %) than the
reference population (LD50 0.013 %; LD90 0.020 %). The results
indicated that resistance to amitraz was developing in R.
(Bo.) microplus. For cypermethrin, no significant susceptibility
change at 95 % confidence was observed in any of the three
species and thus resistance to this chemical was not observed.
Keywords Acaricide resistance . Tick control . Bioassay .
Susceptibility .Amitraz . Cypermethrin
Description
Keywords
Ticks--Control. , Tick-Borne Diseases.