Testing the Pathogenecity of Nomuraea rileyi (Farlow) Samson against Castor Semilooper, Achaea janata Linnaeus

The larvae of II, III and IV instars of Achaea janata treated with subculture I, II and insect cultures of Nomuraea rileyi indicated larval mortalities to be positively correlated with the concentrations of all the three cultures. First subculture and insect culture were almost equally efficacious in causing the disease. Slightly lowered mortality were recorded with subculture II. Reduction in larval mortality was noticed with advancement of the age in A. janata larvae. Almost 100 per cent larvae were dead with 1x10⁸ spores ml-1 concentration when treated in II intar and it was 5-15 per cent when treated in III and IV instars. However, relatively lower concentrations like 1x10⁴ - and 1x10⁵ spores ml^-1 also recorded mortality of 50 per cent and above. The lowest concentration of 1x10² spores ml-1 resulted in 20-30 per cent larval mortality.