Insights into larval development and protein biochemical alterations of Agrotis ipsilon (Hufnagel) (Lepidoptera: Noctuidae) following Beauveria bassiana and Solanum lycopersicum treatments

Abstract

Background The polyphagous notorious pest, black cutworm, Agrotis ipsilon (Hufnagel) (Lepidoptera: Noctuidae), cause significant production losses due to its distinctive feeding and hiding behavior, making it particularly challenging to control it with conventional methods. Therefore, sustainable agriculture demands more effective and environmentally safe pest control solutions. This study aimed to investigate the toxicity of two insecticide alternatives, the entomopathogenic fungus (EPF) Beauveria bassiana and Solanum lycopersicum extract (Tomato plant crude extract, TPCE), using two bioassay methods: the poisoned bait method and the leaf dipping method. In addition, the impact of these biological tools on larval development and protein profiles was evaluated. Results The bait application of both tested materials exhibited higher toxicity than the leaf dipping method, as indicated by the toxicity index. The LC50 values for B. bassiana were 1.6 × 10⁸ and 1.8 × 10⁶ conidia ml−1 using the leaf dipping method and poisoned baits method, respectively. For TPCE, the LC50 values were 4.35 and 1.51 mg ml−1 for the same methods, respectively. In addition, sublethal concentrations of both materials altered the larval and pupal durations. B. bassiana significantly reduced the concentration of larval hemolymph protein. A maximum of 12 protein bands in the control sample, with molecular weights (Mw) ranging between 35 and 120 kDa, were detected by sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE). In B. bassiana-treated larvae, ten bands were detected with Mw ranging from 35 to 120 kDa. At least seven bands were detected in TPCE-treated larvae, with Mw ranging from 35 to 97 kDa. Conclusions The findings of this study can be integrated into management programs for A. ipsilon. In addition, the availability of B. bassiana and TPCE in Egypt and their cost-effectiveness as insecticide alternatives support their use in the management programs of this critical pest. These methods are particularly effective when applied in bait form. Graphical Abstract