Pathogenicity of Beauveria bassiana strain 202 against sap-sucking insect pests

An experimental trial was conducted to determine the pathogenicity of Beauveria bassiana strain 202 (Bb-202) against multiple targeted sucking insect species that are serious pests of crops and ornamental plants. The insect species, Myzus persicae Sulzer (Hemiptera: Aphididae), Jacobiasca formosana Paoli (Hemiptera: Cicadellidae), Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae), and Stephanitis nashi (Hemiptera: Tingidae) were exposed to conidia of B. bassiana at rates of 1.0 × 102, 3.5 × 103, 5 × 104, and 6.75 × 105 conidia/mm2 to determine the pathogenicity of B. bassiana. The fungal strain Bb-202 showed the highest pathogenicity to M. persicae and 100% corrected mortality observed in the treatments over 1.0 × 102 conidia/mm2, followed by the J. formosana with the final corrected mortality of 86.6, 94.4, and 97.4% after 10 days of fungal inoculation with 3.5 × 103, 5 × 104, and 6.75 × 105 conidia/mm2, respectively. The strain Bb-202 also showed good pathogenicity to B. tabaci and corrected mortalities of 77.9 and 81.1% were recorded when exposed to 5 × 104 and 6.75 × 105 conidia/mm2. Relatively weak pathogenicity was observed in S. nashi, in which the highest corrected mortality of 63.7% occurred at 6.75 × 105 conidia/mm2. Accordingly, the LC50 and LT50 values of concentrations 1 × 105, 1 × 106, 1 × 107, and 1 × 108 conidia/ml were calculated for M. persicae, J. formosana, B. tabaci, and S. nashi that were determined as 6.7 × 104, 1.3 × 106, 3.6 × 106, and 1.2 × 107 conidia/ml and LT50 was observed as 5.2~8.24, 5.1~6.6, 7.2~9.0, and 7.9~9.6 in days, respectively.