Pathogenicity of entomopathogenic fungus Isaria fumosorosea on rugose spiralling whitefly Aleurodicus rugioperculatus and its effect on parasitoid Encarsia guadeloupae
2020
Sumalatha, B. V. | Selvaraj, K. | Poornesha, B. | Ramanujam, B.
Highly polyphagous rugose spiralling whitefly (RSW), Aleurodicus rugioperculatus Martin (Hemiptera: Aleyrodidae) invaded India during 2016. Pathogenicity of two strains (ICAR-NBAIR Pfu-1 & Pfu-5) of entomopathogenic fungus Isaria fumosorosea Wize were evaluated against RSW, however, only Pfu-5 showed virulence. Further dose mortality studies were carried out with re-isolated Pfu-5 strain with five different concentrations ranging from 1×10⁴–1 × 10⁸ spores/mL on A. rugioperculatus and its dominant parasitoid Encarsia guadeloupae (Hymenoptera: Aphelinidae). The Pfu-5 strain showed mean mortality of 44.03, 44.80, 36.42 and 28.82% on the eggs, first, third and fourth instar nymphs, respectively. The LC₅₀ values of I. fumosorosea for eggs, first, third and fourth instar nymphs were 2.6 × 10⁴, 2.3 × 10⁴, 3.5 × 10⁵ and 9.5 × 10⁵ spores/mL, respectively, and the LT₅₀ values were 50.39, 41.39, 67.54 and 68.31 h, respectively, for corresponding life stages for the concentration of 1 × 10⁸ spores/mL. The impacts of I. fumosorosea on the parasitoid showed the inhibition of adult emergence was much lower in the Pfu-5 strain (5.8–19.6%) at a concentration of 1 × 10⁸ spores/mL at different exposure times. The present study indicated the pathogenicity of Pfu-5 against A. rugioperculatus and warrant further studies on the compatibility of these biocontrol agents to be evaluated for the simultaneous utilisation under field conditions.
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