Effect of host plant on susceptibility of whitefly Bemisia tabaci (Homoptera: Aleyrodidae) to the entomopathogenic fungus Beauveria bassiana (Ascomycota: Hypocreales)

We determined host plant effect on susceptibility of whitefly Bemisia tabaci to the entomopathogenic fungus Beauveria bassiana under controlled conditions. Insects were reared on cucumber, eggplant, tomato or cabbage. Fungal suspensions of 1 x 10(4), 10(5), 10(6), 10(7) and 10(8) conidia/mL were applied on second-instar nymphs. Nymphal survival significantly differed among different host plant species on which the nymphs were reared. Ten days after inoculation with 1 x 10(8) conidia/mL, percent survival was 4.2 +/- 0.7, 9.6 +/- 0.4, 13.4 +/- 0.8, and 24.3 +/- 0.9% on cucumber, eggplant, tomato and cabbage, respectively. Average survival times of nymphs were also significantly influenced by host plant species. After inoculation with 1 x 10(8) conidia/mL, survival times were 4.8 +/- 0.15, 6.0 +/- 0.11, 5.7 +/- 0.13, and 6.2 +/- 0.08 days for nymphs reared on cucumber, eggplant, tomato, and cabbage, respectively. Virulence also differed depending on host plant species; 10 days after inoculation, LC50 values were 4.6 x 10(4), 1.6 x 10(5), 4.2 x 10(5) and 2.1 x 10(6) conidia/mL on cucumber, eggplant, tomato and cabbage, respectively. Nymphs on cucumber showed highest susceptibility.