Characterization and pathogenicity of newly recorded Clonostachys rogersoniana against woolly apple aphid (Eriosoma lanigerum Hausmann) from India

Abstract

Background Woolly apple aphid (Eriosoma lanigerum Hausmann) (Homoptera: Aphididae) infests the aerial and edaphic portions of apple trees. It is responsible for the serious qualitative and quantitative reduction in apple fruits. This pest is mainly managed by chemical insecticides, so this present study was focused on the isolation of native entomopathogenic fungi (EPF), studying their growth characteristics and virulence against woolly apple aphids. Results Clonostachys rogersoniana, as an EPF from an insect cadaver, was isolated and characterized, using morphological, microscopic, and molecular techniques. To the best of our knowledge, this is the first report of the occurrence of this fungus from India and it is named “C. rogersoniana isolate PUSACR01”. The radial growth and conidial yield of this isolate were excellent on PDAY among ten different culture media, whereas the relative growth rate and conidial germination were good on PDA and CA. The isolated fungus showed 85 and 86.67% mortality rates in adult females of the woolly apple aphid on day 11 at a concentration of 1.0 × 107 and 1.0 × 108 conidia ml−1, respectively. The LC50 values determined by probit regression analysis for days 7, 9, and 11 were 1.12 × 107, 2.52 × 106, and 4.74 × 105 conidia ml−1, respectively, while LT50 for concentrations of 1.0 × 105, 1.0 × 106, 1.0 × 107, and 1.0 × 108 conidia ml−1 were 18.73, 9.39, 6.71, and 5.03 days, respectively. Conclusion Based on the present study, C. rogersoniana would be considered a good biological control agent against the woolly apple aphid in apple orchards.