Rivero-Borja Maribel, Guzmán-Franco Ariel W, Rodríguez-Leyva Esteban, Santillán-Ortega Candelario, Pérez-Panduro Alejandro
Colegio de Postgraduados, Posgrado en Fitosanidad, Texcoco, Estado de México, México.
Departamento de Parasitología Agrícola, Universidad Autónoma Chapingo, Chapingo, Estado de México, México.
Pest Manag Sci. 2018 Mar 7. doi: 10.1002/ps.4884.
The high natural resistance of the fall armyworm (FAW) to entomopathogenic fungi and the speed at which it develops resistance to chemical insecticides make it difficult to control in several crops where it is a key pest. The aim of the study was to improve mortality by combining a 50% lethal concentration of chlorpyrifos ethyl or spinosad with the entomopathogenic fungus Beauveria bassiana (Bb88) or Metarhizium anisopliae (ETL).
Three main results were obtained. (i) Both insecticides improved the performance of the fungus when the insecticide and fungus were applied simultaneously and when spinosad preceded fungi. In control larvae treated with fungi, <1% of larvae showed fungal sporulation, but under simultaneous application of the fungus with chlorpyrifos or spinosad, 31 and 47% did so, with 68 and 93% of cadavers showing sporulation, respectively. (ii) Synergistic mortality was observed when Bb88 and spinosad were applied simultaneously, which resulted in 34% more dead larvae than the spinosad control (44%). Finally, (iii) antagonism occurred when Bb88 was applied before chlorpyrifos, when Bb88 and chlorpyrifos were applied simultaneously, and when ETL was applied before chlorpyrifos, which reduced larval mortality by 27, 31 and 19%, respectively.
The synergistic mortality and improved fungal performance observed here support the hypothesis that combinations of low insecticide doses and entomopathogenic fungi can enhance integrated pest management programs and reduce the environmental impact of insecticides. Antagonism shows that some particular combinations and application sequences may produce disadvantages in pest control. © 2018 Society of Chemical Industry.
草地贪夜蛾对昆虫病原真菌具有很高的天然抗性，且对化学杀虫剂产生抗性的速度很快，这使得它在几种作为主要害虫的作物中难以控制。本研究的目的是通过将50%致死浓度的乙基毒死蜱或多杀霉素与昆虫病原真菌球孢白僵菌（Bb88）或绿僵菌（ETL）混合使用来提高死亡率。
获得了三个主要结果。（i）当杀虫剂和真菌同时施用以及多杀霉素先于真菌施用时，两种杀虫剂均提高了真菌的效能。在用真菌处理的对照幼虫中，<1%的幼虫出现真菌孢子形成，但在真菌与毒死蜱或多杀霉素同时施用的情况下，分别有31%和47%的幼虫出现真菌孢子形成，且分别有68%和93%的虫尸出现孢子形成。（ii）当Bb88和多杀霉素同时施用时观察到协同致死效应，导致死亡幼虫比多杀霉素对照（44%）多34%。最后，（iii）当Bb88在毒死蜱之前施用、Bb88和毒死蜱同时施用以及ETL在毒死蜱之前施用时出现拮抗作用，分别使幼虫死亡率降低27%、31%和19%。
此处观察到的协同致死效应和真菌效能的提高支持了以下假设：低剂量杀虫剂与昆虫病原真菌的组合可以加强综合害虫管理计划并减少杀虫剂对环境的影响。拮抗作用表明某些特定的组合和施用顺序可能在害虫控制中产生不利影响。© 2018化学工业协会。
