| Beauveria bassiana(Balsamo) Vuillemin is a common entomopathogenic fungus and a classical fungal agent which plays an very important role in microbiai control of insect pests. It has been developed into a variety of commercial formulations as mycoinsecticides in some countries. However, there was still no formulation of B. bassiana registered in China although its great contribution has been made in the past three decades. One of the main reasons that prevent it from further research and application is technical problems involving formulation and long-term storage. In this thesis its preparation, storage, formulation and feasible application in forest were studied in order to provide appropriate techniques for preparation of oil formulation of B. bassiana conidia powder. The studies also tried to clarify the relationship between additives added to the oil formulation and viability of the conidial powder during storage, and feasibility in practice by estimating its effects in forest. Meanwhile, pilot studies on another entomopathogenic fungus, Furia gastropachae. were also conducted to select the optimum liquid and solid medium for production. Artificial infection of F. gastropachae was tried and the result showed that it has potential to protect pine trees from Dindrolimus pinctatus.1. Investigation of products of B. bassianaThe gemination, conidial content, water content, and virulence on Dindrolimus pinctatus of some product, collected from different factories, were evaluated respectively. The results showed that there were some differences in various quality estimates. Conidial content of the crude conidia powder were fewer thanconidia g"1, much lower than those of other conidia powder , ranging from conidia g to conidia g Water contents of the products were all above 12%, below the standard requirements for enterprises. The indoor virulence of all the products on Dindrolimuspinctatus was evaluated by dipping in the conidial suspension at concentration of 1 X 10 conidia ml. Mortalities were above 80% generally. Infection rates were mostly above 60%, with the most highest at 84%. LT's were mostly shorter than 5.81d with the shortest at 4.12d. The quality of conidial powder was therefore to be improved before making them into various kinds of formulation although all products caused a high mortality of the insect pests.2. Optimization of components for oil formulations.Main components of the B. bassiana conidia oil formulation prepared previously were further optimized. The conidial powder used in this study was freezing-dried.vacuum-dried, and heat-dried at 38 癈. The effects of the three methods on water content, conidial content, and viability were evaluated. The water content was reduced to 5% by freezing-drying or vacuum-drying after 14h. Conidial content reached 1. 34?. 03X 10" conidia g"1 and viabilities were above 96%. However, water contents were still high even after a long-term drying at 38癈, which undoubtedly resulted in a low viability. Both salad oil and liquid paraffin had comparatively low effect on the viability of conidia after a long-term storage at ambient temperature. By adding additives of 5%VE+0.1%VC. the viability of conidia in oil formulation was still kept above 50% after stored for about 5 months since February. The chemical insecticide. Deltamefhrin, had little effect on the viability of B. bassiana at the concentration of 240 X 10~6mg/l after stored for about 3 months. The results showed that the best concentration of Deltamethrin was between 2-4mg/l when oil dosage sprayed on every insect was kept at O.Sul, and the general mortality was up to 70% in two days, and 80% in seven days.3. Field efficacy of oil formulation of B. bassiana conidia for Dindrolimus punctatus controlConidia powder of B. bassiana Bbl3 was diluted into a concentration of 108 conidia g"' by oil. which was added with different concentrations of Deltamethrin. The field efficacy was conducted at Forestry Extention Center of Tongcheng city, Anhui province, in May of 2002 and iMarch of 2003. resp...
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