Screening and identification of silkworm breeds of Bombyx mori L. for their resistant and susceptible aganist white muscardine

摘要

 Silkworm breeds are highly unpredictable and pathogens are the main cause of diseases in silkworm rearing, diseases are more prevalent in winter and rainy seasons. The major silkworm diseases in India are grasserie, flacherie, muscardine and pebrine. Susceptibility of silkworm breeds mainly due to influence of environmental and nutritional factors. The disease r?sistance mechanism of a genotype has immense value, since the disease resistance results in stability of crop performance and increase in productivity. Fungal diseases are recognized as muscardine or mycoses. Silkworm attacked by more than dozen genera of fungi and white muscardine caused by entomopathogenic fungi of Beauveria bassiana. In Karnataka, white muscardine is named as Sunnakaddi or Sunnakattu roga and Chuna-Kete in West Bengal. The Italian names Calcino, Agostino Bassi, Italian entomologist discover the name of muscardine in 1835. White muscardine disease is rampant in all sericultural areas during winter and rainy seasons, as the humidity increases with the decreases in temperature there is possibility in increase in the spread of muscardine disease in silkworm rearing. The present study was conducted systematically to screen the multivoltine and bivoltine silkworm breeds of Bombyx mori L. and higher dose of conidial B. bassiana concentration 1x107 suspension was used for identify the resistant and susceptible against white muscardine disease. Out of 27 silkworm breeds, the multivoltine breed 2000H and bivoltine CSR6 exhibited relatively more resistant and susceptible breeds. The detail procedure and screening techniques, results and discussion have been dealt in the paper.