COMPATIBILITY OF METARHIZIUM ANISOPLIAE WITH CHEMICAL ACARICIDES

ABSTRACT The combined use of chemical and biological control agents could prove to be a successful strategy against insects and ticks, which could improve the efficiency attained by conventional strategies and also lessen environmental impact that could be caused by these substances. The present study assessed compatibility of the entomopathogenic fungus Metarhizium anisopliae (Metsch.) Sorokin to chemical substances currently used for controlling Riphicephalus (Boophilus. microplus (Canestrini), to verify compatibility of these for possible associated use. The fungus was cultivated in a medium to which was incorporated 40, 55, 70, 85 and 100% of the recommended dosage (RD) of commercial acaricides containing various active ingredients formulated in different compositions. To verify compatibility, fungus vegetative growth, spore production and viability were assessed, and all acaricides were classified regarding toxicity. The chemical acaricides containing chlorfenvinphos + dichlorvos (Amiphós®), cipermetrin + chlorpiriphos + citronelal (Barrage®) and amitraz + chlorpiriphos (Carbeson®) were classified as toxic after causing inhibition of fungal growth and spore production, the last one being the only agent that did not affect fungal viability. The acaricide containing cipermetrin (Colosso®) was classified as compatible and moderately compatible in 40 and 65% of the RD, respectively, and the acaricide containing spinosad (Elector®) was the agent that least affected the factors evaluated, being classified as moderately compatible at 55 to 100% of the RD, and as compatible at 40% of RD. Most of the chemical acaricides evaluated were not compatible with M. anisopliae. The acaricide formulated with cipermetrin and spinosad was the only one that showed some compatibility for use in an integrated pest management.摘要 化学防治与生物防治联合应用或可成为防治昆虫与蜱虫的高效策略，该方案既能提升常规防治手段的防控效率，又能降低此类药剂可能引发的环境负面影响。本研究针对当前用于防治微小牛蜱（Rhipicephalus (Boophilus) microplus (Canestrini)）的化学药剂，与昆虫病原真菌金龟子绿僵菌（Metarhizium anisopliae (Metsch.) Sorokin）的相容性展开评估，以验证二者联合应用的可行性。将含有不同活性成分、以不同配方制备的商用杀螨剂，按推荐剂量（Recommended Dosage, RD）的40%、55%、70%、85%及100%比例掺入培养基中用于真菌培养。为验证相容性，本研究对真菌的营养生长、孢子产量及孢子活力进行了检测，并对所有受试杀螨剂开展毒性分级。含有氯芬磷+敌敌畏（Amiphós®）、氯氰菊酯+毒死蜱+香茅醛（Barrage®）以及双甲脒+毒死蜱（Carbeson®）的化学杀螨剂，因抑制真菌生长与孢子生成而被划为有毒类；其中双甲脒+毒死蜱制剂是唯一未影响真菌活力的受试药剂。含有氯氰菊酯（Colosso®）的杀螨剂，在推荐剂量的40%与65%比例下分别被划为相容与中度相容。含有多杀菌素（Elector®）的杀螨剂对各评估指标的影响最弱，在推荐剂量55%至100%的比例下被划为中度相容，在40%RD下则被划为相容。本次评估的多数化学杀螨剂均与金龟子绿僵菌不相容。仅以氯氰菊酯与多杀菌素为活性成分的杀螨剂，具备用于害虫综合治理的联合应用潜力。