Standardization Of Preparation,Storage And Inspection Of Metarhizium Anisopliae Conidia

Metarhizium anisopliae Sorokin is an entomogenous fungi which has been applied widely in biological control of the agriculture and forestry pests. There have been more than 50 myco-insecticides registered at home and abroad. However, the problems such as standard sample, the standardization of the strain and bioassay etc., have not been resolved successfully, affecting and restricting its deeper exploitation and application. In this research, the standardization of preparation, storage and inspection of M. anisopliae conidia have been studied regarding M. anisopliae IMI330189 as target strain. The main results will offer references to the standardization of fungal pesticides of our country as follows:1. Standardization of preparation of M. anisopliae conidiaThrough inspecting conidial growth characters, the strains stored at 4℃, -15℃ and -85 ℃ needed 4 hours to break the dormancy, the growth was stable after 12 hours. Cultivation of M. anisopliae by ways of Spotting and scraper plate indicated that SDAY was the best medium, and the main item of sporulation was 5.30×108sp/cm2 2.38×108sp/cm2 which were higher than that of the others remarkablely. Furthermore, the characters of cultivation were so stable that SDAY was suggested as the standard medium. The conidia yield began to decrease obviously and the strain produced much more mycelium from the 7th generation after subcultivation. So the srain for mass production was suggested to be rejuvenated at the 7th generation. Bioassay on the strains which were stored at 4℃ for different time indicated that the mortality of Locusta migratoria manilensis dropped to 87% after 30 weeks, so the strain should be replanted or rejuvenated.2. Standardization of storage of M. anisopliae conidiaThe method of scraper plate was better than larynx spray, and the effect of germination inspection was the best after 20²2h cultivation on SDAY with the germination were 99.79⁹9.81%. During storage, the conidial viability which stored at different temperature (room temperature, 4℃, -15℃, -85 ℃ ) and encapsulated with ampere glass melting and centrifuge tube with different water content (23.67%, 8.57%, 6.54%, 3.67%) decreased with the increase of water content and the time of storage. The treatment of ampere glass melting was superior to centrifuge tube under the same storage conditions.The differences of all treatments were exceedingly remarkable (P<0.01). A logatithm law for survival y=a.e^-bt was well fit to the viability data, yielding the time for 50% viability loss (T₅0) and 90%viability loss (T₉0). The results indicated that the conidial viability of the powder stored at room temperature with 23.67% water content dropped to 0 at 130d period of storage. T₅0 and T₉0 of the powder stored at room temperature with 8.57% water content were 78.68d and 259.51d. T₅0 and T₉0 of the powder stored at room temperature with 6.54% water content were 106.09d and 349.95d respectively. The powder with 3.69% water content could be stored under room temperature for more...