Pathogenicity of Metarihizium anisopliae and Beauveria bassiana against the 2nd Instar Larva of Hololtrichia diomphalia Batesa

In order to screen higher virulent entomopathogenic fungus for the biocontrol of Holotrichia diomphalia Batesa, the virulence and effect on the protein content in the blood-lymph of the 2nd instar larva of H. diomphalia after inoculation of three entomopathogenic fungus KMa0107 of Metarihizium anisopliae,strain Bb070610 and Bb070917 of Beauveria bassiana (Balsamo) Vuillemin was tested in the laboratory. Results showed that the lethal dosage caused by KMa0107,Bb070610 and Bb070917 was significantly different, and the lethal time was also significantly different(F＝19.45,P0.01). The logarithmic value of LC50 was (9.451.71)~(4.730.37),(9.761.87)~(5.200.79),(10.481.24)~(5.990.43) for strain KMa0107,Bb070610 and Bb070917,respectively. The LT50 ranged 5.7~8.7d,6.3~8.6d,6.4~9.2d and for H. diomphalia at the concentration of 105~108 spores/mL. The content of the protein in the haemocytes decreased 4 d after inoculation, significantly lower than in the control, and the protein content in blood-lymph in the 2nd instar larvae after inoculation of strain KMa0107,Bb070610 was significantly lower than in the larvae after inoculation of strain Bb070917. Overall,strain KMa0107 of M.anisopliae and Bb070610 of B.bassiana showed high pathogenicity and with biocontrol potentiality against 2nd instar larva of H.diomphalia.