Susceptibility of Tuta absoluta (Lepidoptera: Gelechiidae) pupae to soil applied entomopathogenic fungal biopesticides.
Management of Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) in greenhouses and under open-field tomato cultivation relies on an integrated approach, largely targeting the egg and larval stages of the pest. However, little to no research has been done on the efficacy of EPFs for control of the pupal stage. The aims of this study were to determine the susceptibility of T. absoluta pupae to Beauveria bassiana and Metarhizium anisopliae spores applied as soil drench treatments, and the possible effects of these treatments on fecundity and fertility of moths. The lethal concentrations (LC50 and LC80) of the respective products were estimated in dose-response bioassays by exposing pupae in a soil substrate to different concentrations of EPF products. Emerging moths were paired in different combinations, according to EPF exposure treatments after which fecundity and fertility of females were recorded. Pupae in the soil were effectively controlled by all EPF products in both bioassays as well as in a growth tunnel experiment. The LC50 value of the B. bassiana oil formulation was significantly lower than that of other treatments. The fecundity of females that were subjected to the B. bassiana oil formulation was significantly lower than that of the control treatment. This study showed the potential of soil drench applications of both B. bassiana and M. anisopliae for control of T. absoluta pupae.