Synergistic Effect Of Beauveria Bassiana And Pollution-free Pesticides On Dalbergia Odorifera Leaf-eating Pests

Dalbergia odorifera T.Chen,also known as Hainan huanghuali,is a national secondary protected plant and has important economic value in terms of materials and medicinal use.Sphaerotheca biliformis is one of the main leaf-eating pests on Dalbergia odorifera,with serious regional outbreaks.Chemical methods are often used to prevent and control them,but they are prone to problems such as resistance to pesticides,resurgence of pests,and environmental pollution.Beauveria bassiana can effectively prevent and control pests and has a weak impact on the environment,but it has the disadvantage of poor quick-acting.Using it to properly mix with highly compatible insecticides can improve the efficacy and control efficiency,and reduce the cost of chemicals.The amount is friendly to the ecological environment.In this thesis,the spore powder of the highly virulent strain HB-P-04 of Beauveria bassiana was used to develop an oil suspension emulsion of Beauveria bassiana,and its effect on forest control against Dalbergia odorifera leaf-eating pests;To determine the compatibility of Beauveria bassiana with harmless agents and its combined virulence to Dalbergia odorifera leaf-eating pests;to determine the forest control of Beauveria bassiana and low-concentration insecticides against Dalbergia odorifera leaf-eating pests To establish an efficient control technology for Dalbergia odorifera leaf-eating pests with reasonable mixed use of Beauveria bassiana insecticides and non-polluted pesticides.The main results are as follows:(1)Development of a dispersible oil suspension emulsion of Beauveria bassiana.Through the screening of additives of Beauveria bassiana oil suspension emulsion,it is concluded that the best formula of Beauveria bassiana oil suspension emulsion is 3%spore powder,10%solvent oil sunflower oil,2.5%emulsifier Triton X-100,1%dispersant sodium lignosulfonate,0.35%tackifier xanthan gum,0.7%UV protectant nano ZnO,0.1%antioxidant vitamin C,82.35%distilled water.After testing the quality index of the formulated Beauveria bassiana oil suspension emulsion,it is shown that the suspension emulsion formula meets various quality indexes and is a qualified product.Using Beauveria bassiana oil suspension emulsion to carry out indoor virulence and forest control effects on Dalbergia odorifera double-lined worm pests.The results showed that,at a concentration of 1×107 spores/ml,the effective mortality of Beauveria bassiana oil suspension emulsion against the larvae of S.bilanus was 75.56%,and it had a good insecticidal effect.In the forest test,the relative control effect of the beauveria bassiana oil suspension emulsion on the larvae of the larvae of the larvae reached 78.26%at 15 days,which has a good control effect.(2)Compatibility screening of Beauveria bassiana with non-polluted pesticides and its combined virulence to Dalbergia odorifera leaf-eating pests.By measuring the effects of nine pollution-free insecticides on the spore germination,sporulation and mycelial growth of Beauveria bassiana strain HB-P-04,low-concentration high-chlorflumuron,emamectin benzoate,imidacloprid and white The compatibility of B.bassiana is good,and the extracellular protease content of four kinds of insecticides treated with Beauveria bassiana is determined.It is found that low concentrations of matrine and imidacloprid have weaker inhibition ability on the production of extracellular protease of Beauveria bassiana.good.The synergistic ratio of low-concentration insecticides mixed with Beauveria bassiana was determined,and it was found that when the volume ratio of Beauveria bassiana and matrine was 1:4,the co-toxicity coefficient reached the highest,reaching 223.48.Beauveria bassiana When the volume ratio of the mixed agent with imidacloprid is 1:1,the co-toxicity coefficient is the highest,reaching 168.44,both of which show a significant synergistic effect.(3)The effect of mixed use of Beauveria bassiana and low-concentration insecticides on Dalbergia odorifera leaf-eating pests in the forest.By studying the sequence and interval of applying Beauveria bassiana and the two insecticides to the synergistic effect of Dalbergia odorifera leaf-eating pests,it was found that the treatment with Beauveria bassiana first,and the matrine treatment after 24 h showed a significant effect Synergistic effect,the corrected mortality rate of 9d was 92.86%.The results of the forest test of the matrine and Beauveria bassiana mixed agent treatment group achieved a relative control effect of more than 50%on the 6th day,and the insect population reduction rate reached 82.10%on the 15 d day,and the relative control effect reached 86.42%.The treatment with Beauveria bassiana was first,and the imidacloprid treatment showed significant synergistic effect after an interval of 12 hours.The corrected mortality rate of 9 d was 91.07%.The results of the inter-forest test of the imidacloprid and Beauveria bassiana mixed agent treatment group achieved a relative control effect of more than 60%at 6 days,a reduction rate of insect population of 86.78%at 15 days,and a relative control effect of 89.97%.The stage control effect of the two mixed agent treatment groups at each time point was higher than the stage control effect of Beauveria bassiana oil suspension emulsion.And the relative control effect at 15 d is much higher than that of Beauveria bassiana oil suspension emulsion.The mixed use of Beauveria bassiana,matrine,and imidacloprid can effectively improve the forest control effect of Beauveria bassiana on Dalbergia odorifera leaf-eating pests,and can effectively control the population density of the Dalbergia odorifera pests.