Insecticidal activity of WT and transformant BbVRF1 against H. armigera larvae in laboratory conditions. (A) Survival rates of H. armigera larvae after injection of 5 μL of WT (B. bassiana ARSEF 2860) and BbVRF1 conidia suspensions (1 × PBS) at three spore concentration gradients (2 × 104, 2 × 105, and 2 × 106 conidia mL−1), for a final 1 × 102, 1 × 103, and 1 × 104 conidia per larva (n = 72). (B) Symptoms of H. armigera 8 days after treatment. BbVRF1-treated larvae died in a shorter time compared to WT-infected larvae, and BbVRF1 hyphae were greater in number and stronger than those of the WT strain. (C) Survival rates of H. armigera larvae after topical infection of WT and BbVRF1 conidia suspensions (0.1% Tween 80) at three spore concentration gradients (1 × 107, 1 × 108, and 1 × 109 conidia mL−1) (n = 72). (D) Symptoms of H. armigera 8 days after treatment.