Journal
JOURNAL OF MEDICAL ENTOMOLOGY
Volume 39, Issue 4, Pages 645-651Publisher
OXFORD UNIV PRESS INC
DOI: 10.1603/0022-2585-39.4.645
Keywords
Rhipicephalus sanguineus; Boophilus microplus; resistance; amitraz; discriminating dose; southern cattle tick
Categories
Ask authors/readers for more resources
Modifications of exposure time, substrate, and formulation were made to the Food and Agriculture Organization Larval Packet Test (LPT) to determine a combination suitable for measuring the susceptibility of Boophilus microplus (Canestrini) to amitraz. Exposure time influenced the slope of the dose-response when paper was used as a substrate for amitraz. However, time did not influence the dose-response slope when nylon fabric was used as air amitraz substrate. Formulated amitraz produced results with less deviation from the log-probit model than technical amitraz. The combination of formulated amitraz and nylon fabric as a substrate for amitraz produced results that best fit the log-probit model. The modified FAO procedure (formulated amitraz/nylon substrate combination) was used to assay a Brazilian strain of B. microplus and a Panamanian strain of Rhipicephalus sanguineus (Latreille). Resistance ratios (95% CI) of 26.3 (25.7-26.9) and 7.3 (5.5-9.9) were calculated for the B. microplus and R. sanguineus strains, respectively. A discriminating dose of 0.03% amitraz was determined for B. microplus. This technique will help to locate amitraz resistant tick populations, provide data for improved control practices, and aid in the discovery of resistance mechanisms through synergist studies and verification of molecular techniques.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available