The Production Process Optimization And Micro Powder Processing Of The Acremonium Hansfordii

An Acremonium hansfordii strain of Ahy1 was isolated from natural infected larvae of the Myzus persicae of Yuzhong County, Gansu Province Huang Jiazhuang. It was identified in Anhui Provincial Key Laboratory of Microbial Control, Anhui Agriculture University, and preserved in the Pesticide Analysis Laboratory of Gansu Agricultural University. After the research at early stage, such as the biological characteristics, pathogenic mechanism, infect ability of this strain, we have known that the strain Ahy1 has strong ability to infect. In order to make this entomogenous fungi resource can be used in agricultural production as soon as possible, and to develop fungal pesticides which is suitable for production and application at the drought condition in Gansu province, in this study, the processing technology of strain Ahy1 was further researched, and the additive agents and formulation for micro granule of its conidia were selected. Main results are as follows:1. Through biological assays in the laboratory, additive agents and formulation for micro granule of Ahy1 conidia were selected from 6 carriers, 6 dispersing agents, 5 agglutinants and 5 ultraviolet protectors. The results indicated that the diatomite(carrier), sodium fluorescein and humic acids(UV protectant), sodium lignosulfonate or calcium lignosulfonate(dispersing agent) and carboxymethyl cellulose(agglutinant) had little effect on Ahy1 conidia. And they can be used as the additive agents of micro granule of Ahy1 conidia.2. The quality indicators of above preparations made of the additive agents mentioned was detected. The results are as follows: spores number of 8.0×108 spores/g, water content of 2.36%, spores germination rate of 90.23%,bulk density of 0.37 g/cm3,granule fineness of passing through a 200 mesh sieve, granule diameter of about 74 μm, spores germination rate of 80% after stored for 6 months at 5 ℃. These quality indicators were in line with national standards for powder of Beauveria bassiana(Standard No. GB/T25864-2010), the granule fineness was in line with micro granule.3. The machining process of Ahy1 conidial granule was studied, and the changes of mycelium content, sporulation quantity, p H value and dissolved oxygen(DO) at different times of liquid culturing in fermentation cylinder were determined. The mycelium content achieved the maximum 0.0498 g/m L at 60 h, the sporulation quantity achieved the maximum 1.61×109 spores/m L at 72 h, the p H value achieved minimum 2.24 at 56 h, the DO kept low value during 28 h~52 h and it started to rise from 56 h. Thus the appropriate final time of the fermentation should be selected during 60 h~72 h.4. The condition of solid culture was studied and the results showed that the result of shallow pan cultivation was batter than that of sack cultivation under the same conditions. When it was cultivated adopting in the same way, the sporulation quantity rised along with the increase of environmental humidity, and decreased gradually along with the increasing of thickness of the substrate. The sporulation quantity achieved the maximum through shallow pan cultivation with the substrate thickness of 1cm and humidity of 80%. Multiple consideration of production efficiency and materials utilization rate, it was suitable to keep the humidity between 70% and 80% at the early 5 days, and 50%~80% at the last 3~4 days.5. By the study on production process optimization and micro granule, this part of article take some normative suggestions on operation method, the parameter index and product inspection method to provide the basis for large-scale production.6. The 20% Ahy1 conidial micro granule was tested by laboratory bioassay and field efficacy trials. The result shows that this preparation has good effect to Brevicoryne brassicae, Trialeurodes vaporariorum and Tetranychus urticae. The updated death rate of these three insects which were treated for 7 days by the middle dose(T2, 200 mg/m2) are respectively 67.18%、75.87% and 57.53%,and the field control effect are respectively 61.66%、65.91% and 54.84%. This preparation presents certain residual effect compared with the control insecticides imidacloprid and pyridaben, and it has certain application value in the vegetable greenhouses.