Estudos preliminares para avaliação do uso de compostos análogos do hormônio juvenil no controle de Boophilus microplus (Canestrini, 1887)

Abstract

Four compounds analogs of insect juvenile hormone were evaluated for the control of the cattle tick Boophilus microplus using artificially infested calves and the stall test technique. Two compounds codified as AB 1023 and AB 1043 showed high levels of activity. Engorged females of B. microplus which dropped from treated calves 7 days after treatment were smaller and had a rounded shape when compared with ticks from non-treated animals. The compound AB 1023 reduced hatchability of eggs, increasing the effect from day 3rd after treatment up to day 13th, when a total inhibition was present. Reduction of the number of engorged females were found. The analog AB 1043 also affect egg hatchability and caused reduction in the number of engorged females from day 14th a f t e r treatment. Morphological changes of engorged females of B. microplus were detected from animals treated with the compound AB 1023 by spray at concentration of 1000 ppm (5 liters per animal), pour-on x v i i . ar dose of 43 mg/kg body weight (25 ml per animal at concentration of 20%), and in feed during five consecutive days at dose of 25 mg/kg body weight. Single treatment in feed at dose of 20 mg/kg body weight affect the development of B. microplus, however the results were irregular within the trial. The use of the compound AB 1023 in feed at dose of 25 mg/kg body weight during f i v e consecutive days achieved the best results and had an efficacy of 100% up to 35 days after treatment.