Identification and Conidial Production Characteristics of the Metarhizium sp. Strain Ma130821

Purpose The biological characteristics of Metarhizium Ma130821 was isolated from the infected grub in corn field in E’shan County of Yuxi City, Yunnan Province. To make sure the species and to clarify the potentiality for the biocontrol based on Metarhizium Ma130821.

Method The strain Ma130821 was identified based on the characteristics of morphological, cultural characteristics of microorganism colony and ITS-5.8S gene sequence, the conidial production characteristics was studied in the laboratory at the same time.

Results The strain Ma130821 was identified as Metarhizium flavoviride. The strain Ma130821 could be cultured on rice, corn grain, wheat bran and rice husk, but the sporulation was different on the different medium. The conidia sporulation on the rice media was higher than on other solid mediums under the same culture conditions (P<0.01). The germination rate of spores was also higher than on other three solid media and the germination rate was nearly 100% for 48 h. The optimal temperature for production of spores was at 25 ℃, the sporulation was maximum, significantly higher than that of under the 28 and 30 ℃ (P<0.01), it was 1.47×10⁹ spores/g. The germination rate of spores was 100% after the culture for 48 h. The optimum photoperiod for spores production was at the 16 L:8 D photoperiod with a sporulation of was 5.07×10⁸ spores/g, which was significantly higher than that under the14 L:10 D photoperiod.

Conclusion Based on the above results, the rice medium was suitable for expanding culture of Ma130821, the optimal condition was 25℃ and photoperiod of 16 L:8 D.