Extraction, Isolation, Structural Identification Of Crude Extracts From Metarhizium Anisopliae And Toxicity Testing Against Several Important Pests

In this article, five isolates of Metarhizium anisopliae were selected from different collections and locusts to study yield of the crude toxin, bioassays of metabolite to Locusta migratoria manilensis (Meyen), bioassays of several strains'crude extact to locusta migratoria manilensis (Meyen), Ostrinia furnacalis (Güenée), and Plutella xylostella, identification of destruxin A and B by thin layer chromatography.The primary results are as follows:1. The crude toxin is distilled through seeding cultivatation, liquid ferment, filtration, extraction and vacuum concentration. The yield of crude extact is as follows: LF07's is at best, LD04's takes second place and LB08 is least; the yield is 0.728 g/L, 0.479g/L and 0.084g/L, respectively.2. Five metabolites are injected into fifth larvae of L. migratoria manilensis and the results are: all of the metabolites are toxic to L. migratoria manilensis, but LF07's toxicity is at best, LD04's takes second place and LB08 is least. The mean mortality are 76.67%, 60% and 6.67%, respectively. And the LT50 of LD04 and LF07 are 3.7545 dates and 6.3232 dates.3. The injection experiment of the two crude toxins to L. migratoria manilensis shows the results: the crude toxins distilled from LD04 and LF07 had no contact toxicity to L. migratoria manilensis. But in injection assays, the LC₅₀ of LD04 and LF07's crude toxins are 0.0843 g/mL and 0.1545g/mL, respectively. When the concentration of LD04 and LF07's crude toxins is 0.15g/mL, the LT50 is 1.7768 dates and 5.8660 dates, respectively. When is 0.10g/mL, the LT50s is 5.0519 dates and 8.4806 dates. 4. The contact experiment of the two crude toxins to O. furnacalis Güenée shows the results: in immersion assays, the LC₅₀ of third larvae are 0.0668 g/mL and 0.0747g/mL respectively in the effect of LD04 and LF07. When the concentration of LD04 and LF07's crude toxins is 0.10g/mL, the LT50 is 1.9249 dates and 4.0513 dates.5. The contact experiment of the crude toxin to P. xylostella shows the results: in immersion assays, the LC₅₀ of third larvae is 3.72 mg/mL in the effect of LD04. When the concentration of LD04's crude toxins are 8 mg/mL,6 mg/mL and 4 mg/mL, the LT50 is 0.0144 dates,0.2695 dates and 3.5573 dates, respectively.6. Destrxin A and B were identified through the method of TLC and the results are: the crude toxin of LD04 and LF07 contained Destrxin A and B, while destrxin A and B have not been detected in LA06, LB08 and LC11. the content of Destrxin A and B in LD04 are 0.1 g/L and 0.04g/L, respectively. And in LF07 are 0.07 g/L and 0.02g/L, respectively.