Biocontrol potential of selected botanicals and Beauveria bassiana (Bals.) spore suspension against Bemisia tabaci (Genn.)

This study aimed to evaluate the effects of plant extracts of Capsicum annuum, Datura stramonium and Allium sativum and the fungus Beauveria bassiana on different developmental stages of Bemisia tabaci. The D. stramonium extract achieved the highest adult mortality rate of 92.4% at 4% w/v concentration after 96 hours of exposure, which was higher than A. sativum (85.7%) and C. annuum (76.3%). The isolated D. stramonium extracts demonstrated maximum lethal activity against the early developmental stages of B. tabaci, with second instar showing the highest vulnerability and mortality rate of up to 97.8%. B. bassiana exhibited maximum pathogenicity against B. tabaci life stages, specifically with the second instar nymphs showing the highest susceptibility at 93.6% mortality when treated with 1×108 conidia · ml–1. The combination of plant extracts with B. bassiana resulted in elevated mortality rates with all combinations demonstrating synergistic effects with co-toxicity factor (CTF) values > 20. Lethal potency emerged from the combination treatment of D. stramonium (1% w/v) and B. bassiana (1 × 106 conidia · ml–1), which reached a maximum adult mortality of 98.0% ± 2.1. Greenhouse trials showed that this combined treatment generated population reductions exceeding 90% across all life stages, including adult insects, nymphs, and eggs within 14 days. These findings confirm that both botanical extracts and B. bassiana are suitable components for developing sustainable Integrated Pest Management (IPM) programs due to their efficient and environmentally friendly insect pest control properties.