Susceptibility of three Eco-races of tropical Tasar silkworm to Antheraea mylitta cytoplasmic polyhedrosis virus (AmCPV)

Pathogenic infection in tasar silkworm, Antheraea mylitta Drury. is common and there is a breed specific response regarding tolerance. Observations reveal the possibility of differential response by haemocytes to microbial infection in different breeds. Hence, the susceptibility of three eco-races of tasar silkworm viz. Daba, Sarihan and Raily to Antheraea mylitta Cytoplasmic Polyhedrosis Virus (AmCPV) infection and difference in total haemocyte counts were tested. The survival of Daba, Sarihan and Raily eco-races was significantly different (p < 0.05) when challenged with the same concentration (1 x 105 polyhedra/ml) of AmCPV. Daba eco-race was more tolerant to the AmCPV infection having higher survival (66.7%) and LC50 values (1000893.1796 polyhedra/ml) of AmCPV followed by Sarihan eco-race (50.7% survival and LC50 value of AmCPV 187203.6168 polyhedra/ml.) and Raily eco-race (25.3% survival and LC50 value of AmCPV 5176.37 polyhedra/ml.). Difference in total haemocyte count i.e. higher in tolerant (Daba) and lower in susceptible (Raily) eco-race may be in response to difference to their susceptibility to AmCPV infection.