Occurrence of Entomopathogenic Fungus, Beauveria bassiana (Bals.) on Potato Whitegrubs in Himachal Pradesh

Survey to isolate and identify the entomopathogenic fungi associated with whitegrubs was conducted in Himachal Pradesh during 2008 and 2009. The whitegrubs were collected from 14 locations and Beauveria bassiana (Bals.) was found to be associated with grubs of Brahmina coriacea (Hope) in Shillaroo and Kheradhar areas. The fungus infected grubs were observed only in higher hills of Shimla and Sirmour districts. At Shillaroo, 0.98% grubs of B. coriacea were observed to have fungal infection, whereas at Kheradhar 20.2% of the grubs showed symptoms of mycosis. When field collected grubs were reared separately location- wise in laboratory, very high percentage of mycosis (55.29%) was recorded. Kheradhar and Shillaroo populations of whitegrubs showed white muscardiane infestation in 8.72 and 5.27% of the grubs, respectively. Conidia of the fungus were globose to subglobose measuring 2.0-3.0×2.0-2.5 μm. Incubation of Shillaroo, Kheradhar, Kharapathar and Solan isolates was done at 20, 22 and 26 °C. After 15 days, the radial growth of Shillaroo isolate of B. bassiana was recorded to be 7.66 cm as compared to 7.60, 7.60 and 7.36 cm for Kharapather, Solan and Kheradhar isolates, respectively.