Pathogenicity And Biology Of Nomuraea Rileyi

The muscardin fungus, Nomuraea riIeyi (Farlow) Samson, is a potentialmycoinsecticide for use against noCtuid pests. However, the research of thisentomopathogenic fungUs was stiIl at the beginnings in China. A isolate from Fujian. wasinvestigated on its pathogencity biology and the method of mass-produced, the results areas fOllows:The results of pathogencity tests indicated that N rileyi was highly virulent to 2--5instar larva1 of LaPtwa extwa (HUbner) and Prodenia litura (Fabricius), respectively.The younger the insect was the more susceptible according to the LC5o va1ues. The hostrange tests with another 7 inseCt species demonStrated that the pathogen was not infectiveexcept Heliothis armlerra (Hubner) and Leucania smpta (Walker).For mycelium groWth, the beSt carbon source was soluble starch, the best nitrogensource was fish peptone, the optimal carbon-to-nitrogen ratio was 30--60fl. Adding themicroelement, Cu, to the media resulted in greater mycelium production than control, butadding vitamin didn't show significant effects.For colony growth, the best carbon source was raffinose, the best nitrogen source wasyeast eatraCt powdef, the optAnal carbon-to-nitrogen ration was 5fl. Adding themircoelement, Cu, or vitamin H to media have insignificantly enhence the groWth ofcolony.The best carbon source fOr sporulation was lactose and maltose, the best nitrogensource was beef peptone, and the optimal carbon-to-nitrogen ration was 30--60fl. Theaddition of mircoe1ement, Mn, or vitamin H, to the medium cause an increase insporulation than control.Mycelium groWth, colony growth and sporulation had been fOund to occur betweenl 5--32t, pH 4~12, and to cease at 5l0C and 335C, SpH3 and 3pHl3. The optimaltemperature and pH value were 25OC and pH6~7, respectively. Light had been shown tofavor for their groWth, exposure to light all day long (24h) could accelerate colony grotrthand produce more spores.According to the best nutrition factors fOr sporulation, obtained a optimal solid-phagesporulation media by twice orthonormal experiment which consisted of lactose, beefpeptone, yeast eXtract powder and vitamin Bl. There was no significance difference onsporu1ation between this media and Sabouraud's maltose agar and 1% yeast extract(SMM).The results of experimenis indicated that the substrates sorghum, wheat, and soybeanwere effective for sporulation of N riley. The highest conidial preparation on the substratesoybean was yielded at l4 day. Adding l% lactose to the soybean cou1d enhance thesporulation, but there was no difference when added yeast eXract powder.