Study on Mass Production of Beauveria bassiana (Bals.) Vuill. for the Management of Rice Hispa, Dicladispa armigera (Olivier)

Abstract

Rice hispa D. armigera is one of the most important constraints to crop production globally. It attacks the vegetative stages of summer rice causing 35-65% loss and post flooded transplanted rice causing 100% loss in yield throughout Assam and hence it is regarded as one of the major limiting factors in rice production in Assam. Beauveria bassiana (Bals.) Vuill. is a naturally occurring potent entomopathogenic fungus which has been successfully utilized for controlling many insect pests of rice including rice hispa. For developing a good formulation, Beauveria bassiana (Bals.) Vuill (Strain AAU-09) is mass cultured in the potato broth, rice gruel, coconut water, rice husk, sawdust and rice bran. It was seen that amongst the solid media ,rice husk in addition of 2% dextrose was the best in terms of spore production (6.25 x 107 conidia/ml) and pathogenecity (86.67%) to Dicladispa armigera (Olivier) (Coleoptera: Chrysomelidae) adults. Likewise, amongst the liquid media potato broth supplemented with synthetic chitin (2%), dextrose (2%) and peptone (2%) supported maximum spore production. Chitin is essential not only for spore production but also increasing the power of penetrating on cuticle.