Pathogenicity of Beauveria Bassiana Against the Whitefly (Bemisia Tabaci) on Tomato Plants Under Laboratory Conditions

Abstract

The pathogenic efficacy of Beauveria bassiana against Bemisia tabaci adults and second-instar nymphs on tomato plants was evaluated under laboratory conditions and the effect of exposure time and application rate of conidia on the adults and second-instar nymphs of B. tabaci was investigated. The three concentrations of conidia (1 × 106, 1 × 107 and 1 × 108 conidia/mL) and the control treatment were tested. Mortality was observed at day 3, 5, 7 and 10 following treatments. The higher the concentration of conidia, the higher the number of deaths in both developmental stages, and the longer the exposure time. In adults, the 1 × 108 conidia/mL treatment produced the highest mortality (86.6%) after 10 days, followed by 65.7% and 53.4% at 1 × 107 and 1 × 106 conidia/mL, respectively. The reported LT50 values decreased from 8.72 days at 1 × 106 conidia/mL to 6.76 and 4.93 days at 1 × 107 and 1 × 108 conidia/mL, respectively. There was no mortality in the control treatment. In nymphs, the highest mortality was 78.7% at 1 × 108 conidia/mL after 10 days, compared with 62.0% and 51.0% at 1 × 107 and 1 × 106 conidia/mL, respectively. The reported LT50 values were 9.34, 8.15, and 6.22 days at 1 × 106, 1 × 107, and 1 × 108 conidia/mL, respectively. The results showed concentration and time-dependent pathogenic activity of B. bassiana against adults and nymphs of B. tabaci, which confirmed its suitability for biological control in IPM of tomato whitefly.

Keywords: Beauveria bassiana; Bemisia tabaci; whitefly; biological control; entomopathogenic fungus.