Diferentes adjuvantes e Metarhizium rileyi (Farlow) no controle de Helicoverpa armigera

Abstract

Helicoverpa armigera (Lepidoptera: Noctuidae) is an extremely polyphagous species. Its caterpillars have been recorded feeding on cultivated and wild plants belonging to 67 botanical families. The biological control of this pest is a tool for the use of chemicals, with the combined use of parasitoids, predators and entomopathogenic microorganisms. Objective of this bioassay was to evaluate the effect of different adjuvants and the entomopathogenic fungus Metarhizium rileyi isolate UFMS 03 on H. armigera caterpillars. The treatments were composed of: T1- sterilized distilled water, T2- fusel oil (0.5%), T3- fusel oil (1.0%), T4- fusel oil (1.5%), T5- Protac®

(0.5%), T6- Protac®

(1.0%), T7- Protac®

(1.5%), T8- Nimbus®

(0.5%), T9- Nimbus®

(1.0%), T10- Nimbus®

(1.5%), T11- Aureo®

( 0.5%), T12- Aureo®

(1.0%), T13- Aureo®

(1.5%), T14- M. rileyi

(1×109 con. mL-1 ). A 2 mL/repeat of each treatment was applied using Potter's Tower. Cumulative daily mortality percentage and efficiency were calculated using Abbott's formula. All data were submitted to variance analysis (F test), and the means were compared using the Scott-Knott test at 5% probability. The adjuvants Nimbus® , Aureo® in all concentrations tested and Fusel oil (1.5%) provided mortality above 80% to caterpillars at six days after application. With the exception of Fusel at the lowest concentration, taking into account the efficiency, all others showed values above 80%. Perhaps the efficiency should be taken into account more than the accumulated mortality, because in the efficiency, due to the discount of mortality in the control, we are sure of the death caused by the treatment.