In vivo effect of diflubenzuron, administered via mineral salt supplementation, against Haematobia irritans and Rhipicephalus microplus parasitizing cattle

Abstract This study involved two field trials with the aim of evaluating the efficacy of diflubenzuron, via mineral supplementation, against Haematobia irritans parasitizing cattle. Concomitantly with the main trial, a stall test was conducted to ascertain the effects of a different formulation with the same active ingredient against Rhipicephalus microplus, along with the action of diflubenzuron on the reproductive parameters of R. microplusfemales that had naturally detached from cattle. Against H. irritans, it was observed that the efficacy indexes fordiflubenzuron were low (≤ 31.3% or 44.6%) or null (0.0%) throughout the study. The anti- R. microplus efficacy of diflubenzuron, at weekly intervals, ranged from 0.0 to 13.7% over the entire experimental period. Null efficacy (0.0%) was registered for diflubenzuron in relation to the reproductive parameters of R. microplusfemales that had naturally detached from cattle. The different diflubenzuron formulations, administered via mineral salt supplementation, did not show satisfactory efficacy indexes against H. irritans and R. microplus parasitizing cattle, within the experimental design of the present study. In addition, this agent did not present any deleterious effects on the reproductive parameters of R. microplus females.摘要 本研究开展两项田间试验，旨在评估通过矿物质补充剂（mineral supplementation）施用的除虫脲（diflubenzuron）对寄生在牛体上的厩螫蝇（Haematobia irritans）的防治效果。主试验同期开展一项圈舍试验（stall test），以确认含有相同有效成分的不同剂型对微小牛蜱（Rhipicephalus microplus）的防治效果，以及除虫脲对自然从牛体脱落的雌性微小牛蜱繁殖参数（reproductive parameters）的影响。针对厩螫蝇，本研究全程观测到除虫脲的防治指数较低（≤31.3%或44.6%）甚至无效（0.0%）。每周施用的除虫脲对微小牛蜱的防治效率在整个试验周期内介于0.0%至13.7%之间。对于自然脱离牛体的雌性微小牛蜱繁殖参数，除虫脲未表现出任何防治效果（0.0%）。在本研究的试验设计框架内，通过矿物质盐补充剂施用的不同除虫脲剂型，对寄生牛体的厩螫蝇和微小牛蜱均未展现出令人满意的防治效果。此外，该药剂未对雌性微小牛蜱的繁殖参数产生任何有害作用（deleterious effects）。