PERFORMANCE OF Metarhizium rileyi APPLIED ON Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae)

Abstract

This study aimed to evaluate the efficiency of different strains of the entomopathogenic fungus Metarhizium rileyi in the control of Helicoverpa armigera caterpillars in laboratory conditions. Caterpillars between the 2nd and 3rd instar were used, ranging in size from 0.7 to 1.2 cm length. The experimental design used was completely randomized, composed of five treatments and five replications, each one consisting of 50 insects. The treatments T1 - Control (sterile distilled water), T2 - M. rileyi UFMS 02 strain, T3 - M. rileyi UFMS 03 strain, T4 - M. rileyi UFMS 06 strain, and T5 - M. rileyi UFMS 07 strain were evaluated. All treatments were applied (2 mL/insect) in suspensions of the order of 1.0 × 109 conidia mL-1, and Tween 80® was added in all treatments. Evaluations were performed daily to verify mortality and sublethal effects. For emerging adults, Filial Generation (FG), the biological cycle was evaluated. The data referring to larval mortality for the Parental Generation (PG) and GF and pupal for GF were submitted to analysis of variance, and the Scott-Knott test grouped the averages at 5% probability. The strains tested did not provide pathogenicity in the larval phase of H. armigera for PG and FG. However, there was a reduction in oviposition in all treatments regarding the control. There was an effect on the reproductive phase of GF caterpillars exposed to M. rileyi.