Study On The Biocontrol Effect And The Metabolites Activity Of Four Entomogenous Fungi

Agriculture is the foundation of the national economy, the pesticide is an important productionmaterials of agriculture. In the production practice, the control of common major crop insect pests anddisease is often dependent on chemical pesticides. Up to now, chemical pesticides is still the mostcommonly used as pest and disease control methods in the agricultural and forestry production, the role ofchemical pesticides, emergency short-term effect is almost up to80%; however, the effect, Long-term use alarge number of chemical pesticides, is not ideal, not only increases the cost of production, and its repeatedapplication inevitably leading to environmental pollution, pest resistance generated and pesticide residuesin agricultural. Therefore,the biological control of pest more and more attention by people.Research shows that entomogenous fungi are the only pathogenic microorganisms that can infect theinsect by contact with insect′s body wall under natural conditions, Control of pests with entomopathogenicfungi are safer for plants, animals and the environment, can regulation of many insect populations in thenatural, and cause often widespread epizootics under ideal environmental conditions.So, entomogenousfungus plays more and more important role in biological control. The new antibacterial, insecticidal activesubstances with new structure or active ingredients need screened out in the process of disease and pestcontrol in order to meet the production needs. The entomogenous fungi species-rich, the metabolic typecomplexity of the, can produce variety of biological active substances with specific functions, it is providean important new avenue of resources for the development of new bio-pesticides in the process of diseaseand pest control. In this article, four entomogenous fungi strains as research material, the effect ofbiocontrol and metabolite activity was measured, research results are as follows:1The four entomogenous fungi strains identified by morphological and molecular biology, the resultsprove that: the strain BP-1and strain BP-2is Beauveria brongniartii, the strain MA is Metarhiziumanisopliae, the strain BV is Beauveria bassiana.2The biological characteristics of different strains were measured, the results found:(1) Thetolerability to low temperature is different in different strains or different strains of the same species offungi.(2) The pH adaptive range of Beauveria brongniartii strain BP-1, Beauveria brongniartii strain BP-2and Beauveria bassiana strain BV is widely, they can growth better in the range of pH5.5to8.5, the pH adaptive range of the Metarhizium anisopliae strain MA is narrow, the range of pH7.0to7.5is suitable forits growth.(3) Entomogenous fungi strains need to a certain amount of carbon and nitrogen sources in thegrowth process, the influence of carbon and nitrogen sources was different in different strains, comparedwith utilization of nitrogen sources, entomogenous fungi have substantive differences with utilization ofcarbon source.(4) The growth of entomogenous fungi strains was different in different culturemedium,there is no "universal medium" suitable all strains to achieve the best growth conditions.(5)Thesolvent naphtha has very good protection with the spores of entomogenous fungi, can improve thegermination rate of conidia significantly, the effect can be achieved40%.3The insecticidal activity of strains was tested in laboratory: They have certain cytotoxicity of theBeauveria bassiana strain BV, Metarhizium anisopliae strain MA, Beauveria brongniartii strain BP-1andthe Beauveria brongniartii strain BP-2to Lipaphis erysimi, the corrected dead rate was27.61%to35.44%after7days.The same four strains have not strong cytotoxicity to larva of Herdonia osacesalis Walker inlaboratory, almost no cytotoxicity, the corrected dead rate was0to4.54%after5days.The Beauveriabrongniartii strain BP-1and the Beauveria bassiana strain BV of the four strains have the strongestcytotoxicity to Epacromius coerulipes in laboratory, the corrected dead rate was51.86%to55.56%after26days; The Metarhizium anisopliae strain MA and the Beauveria brongniartii strain BP-2have the weakercytotoxicity to Epacromius coerulipes in laboratory, the corrected dead rate was3.7%to25.92after26days.The impact on the natural enemies of insects:The pathogenicity is presence of entomogenous fungi tonatural enemies of insects, but the impact is small, taking into account the coercive of living conditions inlaboratory to natural enemies of insects, the impact in the field may be smaller.The inhibitory effect of five chemical pesticides was tested on the colony growth to fourentomogenous fungi strains. Results showed that there were have certain inhibition to strains in theconventional concentration of25%Chlorbenzuron(SE),2.5%Lambda-cyhalothrin(EC),70%Acetamiprid(WDG),16000IU/mg Bacillus thuringiensis(WP) and4.5%Beta cypermethrin(EC),but theInhibition is small,the inhibition rate between-32.53%and38.05%.4The insecticidal and bactericidal activity of four entomogenous fungi strains metabolite wasmeasured. Results showed that the entomogenous fungi metabolites have some control effect to diseasesand pests of plant.Thus, extracting insecticidal, antimicrobial substances and drug development byentomogenous fungi metabolites is feasible.