Biology Of Meterhizium Anisopliae And Application In Controlling The Peanut White Grubs

In order to solve a series of problems that the pollution of surroundings and the quality of peanut were set off application of large quantity pesticide; To search after the new application approaches of controlling the white grub; To search after the measure of socially harmless controlling technology. In the thesis, Metarhizium anisopliae was cultured in the glass utensils and cultured widely in jar, study on the biology of Metarhizium anisopliae, and the best culture medium was sifted. At the same time, the virulence of several fungi and the mixture with other fungi to the white grub were determined to sift through the high virulence fungi. And the experiment were made in field for two years to control the white grub with Metarhizium anisopliae and other fungi, And study on the technology of application of Metarhizium anisopliae.1 The biology of Metarhizium anisopliae strain Ma2In these thesis, Ma2 were cultured at three culture medium SDAY, PPDA,Czapek,it showed that the colony form of Ma2 didn't change with the bases of culture medium.the growth of colony diameter of everyday ,the sporulation time and sporulation number were determined ,the result showed that the sporulation time was the earliest, the sporulation number was the largest and the growth speed was the quickest when Ma2 was cultured at the PPDA. At the same time, according the colony diameter increase of everyday and sporulation time of Ma2 on SDAY ,we could know 25℃was fitter to the growth of Ma2 than 15℃and 30℃.2 The filter of the best culuture medium of Metarhizium anisopliae strain Ma3 and Ma4By culturing Ma3 and Ma4 at six culture medium, the result showed that their colony form didn't change with the composition of culture medium.The growth of diameter of everyday, the sporulation time and sporulation number were compared. It showed: the best culture medium that made the colony of Ma3 and Ma4 rapidly expend separately were C and E.But the growth of diameter of everyday and the growth speed were analyzed synthetically, the best culture medium to culture Ma3 and Ma4 was A:sucrose 30g,NaNO33g, KCl 0.5g, MgSO4 0.5g, KH2PO4 1g, FeSO4 0.01g, agar 20g, yeast 5g, H2O 1000ml,Cu(OH)2 0.01g,MnSO4 0.01g.3 The filter of the best culuture medium of Ma3 and Ma4Ma3 and Ma4 were cultured widely in jar, by observing the character and determining the sporulation number, it could be showed that the need on nourishment of different strain of Metarhizium anisopliae were different. Ma3 grew well at the culture medium G; Ma4 grow well at the culture medium H. That's to say, the best culture medium to culture Ma3 widely was G: rice:husk of rice:peptone=7:1:0.5; the best culture medium to culture Ma4 widely was H :potato:husk of rice:husk of wheat:peptone=5:2:3:0.25. At the same time, the character of growth and sporulation would obviously improve if the little peptone were was spplied in addition in the culture medium containing the same composition.4 The virulence of several fungi to the white grub in labThe virulence of Metarhizium anisopliae and other fungi and the mixture with other fungi to the white grub were determined, the result showed that adjust accumulative mortality rates were 62.5%, which is the highest in all treatments. The second was Bbr +Ma3 treatment, the Adjust accumulative mortality rates was 50%, which were better than one of single-use of the two fungi. And comparing with other treatments, the difference was obvious at 0.05 and 0.01 level. Furthermore, the adjust accumulative mortality rates of Ma3 by liquid culturing was higher than one of the spore power of Ma3 .the LT50 of Ma4 was 10.5 days, which was the lowest in all treatments, the second was Bbr+Ma3 and Bbr +Ma4, whose LT50 separately were 15.06 and 15.30 days, but LT50 of only Ma3 and only Bbr separately were 22.95 and 27.56 days, which reach to the lowest level in all treatments, and the LT50 of Ma3 by liquid culturing were lower than one of the spore power of Ma3.5 The effect of releasing fungi in field to control the white grubThe experiments in field to control the white grub were made for two years, the result showed: in the Ma4 treatment, the live insects and the peanut eaten rates were the lowest in all treatments, and the cadaver were the most and the effect were the highest .The effect of the Bt treatment was only lower than Ma4 among all treatments, the body infected by Bt were not seen, but the eaten rates were lower, so the ability of harming the peanuts became weak. It is the Ma3+Bt and Ma4+Bt that the effect is the lowest, which were lower than any one of single-use, so single-use was proposed.