| In order to produce vast amounts of high quality biopesticides, fermentation of Beauveria bassiana and a new kind of biorational pest control formulation, nonwoven fabric band impregnated with B. Bassiana spores, were studied. At the same time, field experiments against Monochamus alternatus and Anoplophora glabripemis were carried out in order to decide a proper way of controlling M. alternatus and A. glabripennis.Wheat bran medium, containing 6% wheat bran filtrate, 1% sugar, 2% soybean powder and 0.05% K,HP04, was found to be the best medium for B. Bassiana in submerged fermentation. The most suitable initial pH was 6.0-7.0, which is the natural pH of wheat bran medium.A technology was developed for mycelium production of B. bassiana in submerged culture. The fungus grew well at 20-25 癈 but very poorly at 30 "C. The biomass fits well to a logistic growth model at a given temperature. Based on observation and modeling, the optimal culture temperature, and harvesting and inoculating time were 25 癈 and 48h respectively.As to solid-state fermentation of B. Bassiana in a 20m3 solid fermenter, a solid medium containing 90% wheat bran, 5% maize flour and 5% soy bean powder was determined to be the best medium with excellent physical properties and sufficient nutrition through an orthogonal test. The spore count of the primary product was 244.7 X108 spores per gram. About 10% moisture was lost duringfermentation and the best moisture proved to be 60-65% for wheat bran medium. The best aeration ratio was: 0 in 12h. 1:1 in 12-48h and 1:2 for fermentation after 48h. To emit heat released by substantial growth of mycelium, it is necessary to control the temperature with air pumping or water cooling from 12h to 48 ?h.The present desiccating and grinding systems in Zhongbang Co. were tested and proved to be unsuitable for B. bassiana because most of the condia were dead after the process. A new desiccating system, which can dry the primary product at normal temperature, is necessary to keep the condia viable.Nonwoven fabric bands impregnated with B. Bassiana spores, a novel fungal insecticide formulation, were developed by a Japanese company. Nitto Denko. for longicorn beetle control. The improvement of the medium for making nonwoven fabric bands with B. bassiana spores was made with a cheaper wheat bran medium at an optimal inoculum ratio of 1:3.5. The suitable inoculating temperature was less than 38癈. and the suitable incubation temperature was 25癈 with an optimal humidity of 90-95% for 6-7 days.Bioassays were carried out against the pine sawyer. Monochamus alternatus and the Asian longhorned beetle. Anoplophora glabripennis. The results were: Bb202 proved to be the most virulent against \t. alternatus among the strains of Beauveria spp.: the MT strain of B. bassiana. and ND strain of B. brongniartii proved to be two of the most virulent strains against A. glabripennis. Ma83. however, was the most virulent strain to both beetle species among the strains tested of entomogenous fungi.In the field test against M. alternatus. Bb202 was used by two different methods, band impregnated with Bb202 and Bb202 spray. The results were: the percentage infected trees in the treated plot declined by 31.1 % as compared to the control plot; the mortality of the M. alternatus larvae was 74.7% in the sprayed plot, 41.2% in the banded plot and 32.3% in the control plot, suggesting that B. bassiana suppressed M. alternatus population to a certain degree.In cage test I against A. glabripennis, two strains, MT and ND, and two application techniques, non-woven fabric fungal bands and spraying, were tested.There were four treatments, ND bands, ND spray, MT bands, MT spray and a control, with 30 cages for each treatment. A total of 150 cages were used. Five beetles, two males and three females, were put into each cage, 750 beetles in total, and were observed for 10 days in the field. The results were as follows: as to the oviposition sites per tree, an average of 16.6 oviposition sites were recorded... |
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