| Vegetable pests such as Pieris rapae, Plutella oxlostella and Pyralidae Lepidoptera endanger vegetable growth and production. For over 60 y, chemical pesticides have been the prevalent tool for insect, weed, and plant disease control. Interest in the use of biologically based pest control measures has been brought about by the development of pest resistance to many chemical pesticides coupled with public concerns about the adverse impact of wide spread chemical use on human health, food safety, and the environment .There is a worldwide resurgence of interest in the use of entomopathogenic fungi as microbial control agents. Metarhizium anisopliae the causal organism for green muscardian disease has been considered as a potential biocontrol agent for wide range of insect pests .The interesting candidate that is widely distributed in nature which infects over 200 species of insects. Metarhizium anisopliae has become widely used in vegetables and a variety of crop pests.Screening high insecticidal activity and broad spectrum Metarhizium anisopliae against 4 kind of Lepidopteran pests from strains of our lab. Morphology-based and molecular identification were used identify taxonomic status. Culture conditions and insecticide toxicity were also studied. A preliminary exploration of formulation of Metarhizium anisopliae against vegetable pests was done according to the characteristics of vegetable pests. Insecticidal effect of this formulation against white grub were evaluated since the strain also has high insecticidal activity to white grubs.①We successfully isolated a strains of Metarhizium anisopliae,whch is high toxicity against several Lepidoptera pests. Morphology-based and molecular identification were used to definite that CQMa128 is Metarhizium anisopliae var.majus.②Toxicity bioassay was conducted against four kinds of lavers of Lepidoptera. By using 1.0 x 108 mL-1 spore suspension to inoculate the fourth-instar larvae of cabbage caterpillar, corn borer and diamond back moth, their percentage rates of corrected immortality were 100%, 83.3% and 76.7%, respectively. The mortality rate for silkworm was merely 10%. The results showed that the strain had highly infectious insecticidal activity to cabbage caterpillar, corn borer and diamond back moth, but relatively safe to silkworm. A time-dose-mortality model was established to analyze the bioassay data and the model passed Hosmer-Lemeshow goodness of fit test . Lethal dose and lethal time of this formulation were estimated by this model. ③By single-factor experiments, we tested and studied the effects of different factors (pH, carbon source, nitrogen source and other microelements) on the strain growth and sporulation. By conducting orthogonal tests at three relatively better levels (carbon source, nitrogen source and microelements), we ascertained the optimal combination of conditions for fermentation, concluding that the best medium for fermentation were: pH; 7.0; 10.0g sucrose, 1.5g peptone; 3.0g yeast extract with additional 0.01% Mg ion. Sporulation of strain CQMa128 was increased 51.9% and biomass doubled compared with basal liquid medium.④A wide range of surfactants were screened.Surfactant Sp80, T80 were recognized good additives, they can increase the storage period and improve activity of emulsifiable powder formulation .The best proporation of additives,oil and spore powder were 8%-10%, 25%-30%and 60%-70% respectively. Emulsifiable powder formulation, which have high activities and good qualities. Emulsifiable powder formulation has a wide application as a bio-control agent.⑤A concentration of 5×107 Metarhizium anisopliae spores per gram proved effective in controlling the grubs and the corrected mortality rate reached 85.2%. Emulsifiable powder formulation of Metarhizium anisopliae CQMa128 is a potential formulation in preventing and controlling grubs biologically.
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