Effect of nuclear polyhedrosis virus on botanicals treated larvae of Bombyx mori L.

Laboratory testing of virulence of two BmNPV stains KRI 1 and DMI 1 tested against multivoltine silkworm breeds showed that the KRI-1 stain showed high mortality of 75.03 per cent in Pure Mysore followed by Tamil Nadu White (73.66%) while C. Nichi recorded minimum of 61.0 per cent mortality. Another study conducted on the efficacy of botanicals against multivoltine breeds, viz., Nistari, C. Nichi and Tamil Nadu White infected with BmNPV revealed that Plectranthus amboinicus recorded significantly lesser mortality of 34.60 per cent, 30.10 per cent and 33.00 per cent, respectively and was on par with Psoralea corylifolia (35.65%, 29.33%, 34.00%) against the mortality of 60.00 per cent (Nistari), 59.00 per cent (C. Nichi) and 52.00 per cent in Tamil Nadu White, respectively. Results on the response of the above breeds to a particular treatment revealed that mortality was significantly lowest in C. Nichi for both the treatments, P. corylifolia (29.00%) and P. amboinicus (31.10%), followed by Nistari (34.60%, 35.65%).