Method for production of Paecilomyces tenuipes utilizing the naked-pupa mutant silkworm.

To shorten the labor cost for the production of the fungus, Paecilomyces te nuipes, the use of uncocooning mutant silkworm as a host was examined. The strain Nd was selected as the best for the production of P tenuipes among f ive strains (Nd, Nd-H, p(3)Nd, Nd-s and Nd-t). Nd yielded the highest pupat ion rate of 95%, naked pupation rate of 99% and pupal weight of 1.4 g/indiv idual. The optimum time for the infection of P tenuipes was 12 h at 28.5 de greesC and 95% R.H., when 10(8) conidia/ml of P. tenuipes were sprayed on t he surface of the silkworms. The yield of P tenuipes was reduced when Nd wa s used as a host because Nd was smaller than the hybrid Baegokjam. that has been used as a typical host. To increase the host weight, Nd was crossed w ith Jam123 or Jam124, and resulted in not only greater weights (> 1.2 x) bu t also higher yield (>1.5 x) of P. tenuipes.