In vivo compatibility of tank-mix with herbicides and entomopathogenic fungi for the management of Dalbulus maidis (Hemiptera: Cicadellidae)

Resumo

The critical period for weed incidence coincides with that of the key insect pests of initial stages of corn crop, as is the case of Dalbulus maidis (Hemiptera: Cicadellidae), the most important pest of corn crops. Due to operational advantages, mycoinsecticides and herbicides are commonly used concomitantly in tank-mix, aiming to increase the spectrum of arthopod-pests and weed control. Therefore, we evaluated the in vivo compatibility, using D. maidis adults, of seven herbicides used in corn crops with two mycoinsecticides, formulated based on the Simbi BB15 isolate of Beauveria bassiana and Esalq-1296 of Cordyceps javanica (both Hypocreales: Cordycipitaceae). Through bioassays by topical application, we identified that the highest mortality rate (58%) was observed in the treatment using the herbicide glyphosate (SL formulation) in combination with the fungal isolate Simbi BB15 of B. bassiana (FlyControl®). Still, in general, when herbicides were mixed with mycoinsecticides, the probability of insect survival was reduced compared to the same treatments applied alone. However, there were no cadavers with fungal extrusion when any herbicide was mixed with one of the mycoinsecticides tested.