the effects of natural substrates on the sporulation and viability of conidia and blastospores of metarhizium anisopliae

In this study the effects of natural grain-based media on the sporulation and germination of conidia and blastospores of metarhizium anisopliae were investigated. experiments were conducted with factorial arrangement in a completely randomized design with nine treatments and three replications. the obtained results showed that there was significant difference in the yield of conidia among different treatnents, two weeks after inoculation, (f= 4.66, df= 7, 16, p<0.01). highest average yields were obtained as 3.1×10^8 and 3×10^8 conidia/g in rice flour and sabouraud’s dextrose agar with 1% yeast extract, respectively. the lowest level of conidia yield was 4×10^6 conidia/g which obtained in the wheat bran medium. there was significant difference between blastospores yields four days after inoculation of the media, (f=2.57, df= 8, 18, p<0.05). the highest and lowest average yield of blastospores were 6.1×10^8 and 4.5×108 blastospores/ml and were obtained in the wheat bran+rice bran+yeast extract and rice bran+yeast extract media, respectively. analysis of variance of nutritional and chemical amendments which were added to blastospores media showed significant differences in the yield among different treatments (f=5.02, df=13, 29, p<0.01). the highest average yield of blastospores were 6.6×10^8, 6.1×10^8 and 5.7 ×10^8 blastospores/ml which were obtained in the rice bran+wheat bran+yeast extract+whey powder, rice bran+wheat bran+yeast extract, and wheat bran+rice bran+magnesium sulfate media, respectively. the lowest average yield of the blastospores was obtained in the media containing grape juice. results also showed significant difference between the means of germination rate of conidia one, two and three monthstorage at 4°c and 25° c. the highest germination rate belonged to treatments stored in the refrigerator.