| The plant disease is one of the main factors affecting crop yield and quality, at present,on the agricultural production of our country, the main prevention and control of plant disease is the use of chemical fungicide, but long-term heavy use of chemical fungicides had had a serious resistance of pathogenic bacteria, at the same time cause crop pesticide residues, environmental pollution, harm human health, destruction of ecological balance,biological control has been paid to more and more attention. There are variety of insect fungus, widely distributed, it is a kind of precious raw resources. Bbr12, Bbr14, Bbr17(B.Brongniartii) and Mf04, Mf06, Mf82(M. Flavoviride) are the main objects of this study,preliminary inquiry fungal species on common pathogenic fungi of antagonism, as well as analyze the physical and chemical properties of the fermentation broth for the insect fungus used in the field application of plant disease biological control, and the fungi fungicides provide theoretical basis for the development. The main results were as follows:1 The result of tablet confrontationsThrough the tablet confrontation experiment, three B. Brongniartii strains were found have certain inhibition against four common plant pathogens, among them, the inhibitory rate of the Bbr12 strains against P. Grisa, S. Scleotiorum, R. Cerealis, B. Maydis reached25.78%, 49.05%, 51.08%, 44.39% after 5 days. The results show that the Bbr12 inhibition effect against four kinds of plant pathogenic bacteria are: R. Cerealis>S. Scleotiorum>B.Maydis>P. Grisa.The inhibitory rate of Mf04, Mf06, Mf82 against B. Maydis respectively were 38.31%, 34.22%, 45.06% after 5 days, among them, the inhibitory rate of Mf82 strains against B. Maydis was the highest.2 The antagonism between B. Brongniartii and several important pathogenic fungiIn the study, through the determination of the inhibitory effect between three different concentrations of B. Brongniartii spore suspension and the four kinds of plant pathogens fungi, the results show that the inhibitory effect of the three kinds of B. Brongniartii spore suspension against the four kinds of plant pathogens fungi were enhanced with the increase of concentration of spore suspension, among them, the inhibitory effect of conida concentration of Bbr12 strains against P. Grisa, S. Scleotiorum, R. Cerealis, B. Maydis were the best, at conida concentration of 4.25 ×106cfu·m L-1, the inhibitory rate can reach46.57%, 68.21%, 70.43%, 76.15% after 6 days. Cultured 16 days on the Bbr12(B.Brongniartii) fermentation solution,which mixed with PDA medium were inoculated four kinds of pathogens fungi, show that the inhibitory rate of conida concentration of Bbr12 strains against the four kinds pathogens fungi reached 32.45%, 55.24%, 58.36%, 46.33%after 5 days.3 The antagonism between M. anisopliae and B. MaydisThrough the determination of the inhibitory effect between three different concentrations of M. Flavoviride spore suspension and B. Maydis, the result show that there were some certain inhibitory effect between the Mf04, Mf06, Mf82(M. Flavoviride)spore suspension and B. Maydis, at conida concentration of 4.25×106cfu · m L-1, the inhibitory rate can reach 63.46%, 62.44%, 66.94% after 6 days. Among them, Cultured 16 days on the Mf82(M. Flavoviride) fermentation solution, the inhibitory rate respectively was 40.46%, 44.27%, 51.76% after 3d, 4d, 5d of the treatment.4 The physical and chemical properties of B. Brongniartii and M. Flavoviride fermentation brothBy measuring the thermal stability, light stability an p H stability of the Bbr12(B.Brongniartii) and the Mf82(M. Flavoviride) fermentation solutions, the result show that the two fermentation solutions both have certain stability under the light, are not easy to decompose. With the temperature rising,the inhibitory rate of the fermentation solutions decrease a bit, only after heating in high temperature of 121?for 30 min, the inhibitory rate decreased obviously. The inhibitory rate of the two fermentation solutions achieved the best inhibiting effect when p H=10, under the strong acid or alkali environment, its inhibitory effect appeared a downward trend. |
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