| Metarhizium fungi is a kind of highly pathogenic entomopathogenic fungi, according to incomplete statistics,the strains can parasitize more than 200 kinds of insects belonging to 8 Orders, 42 Families. Metarhizium×sp is one of the largest research and application of insect fungus, at present, it has been an important role in biological control and has been used for the prevention and control of all kinds of insect pests in many countries.In this dissertation, 19 strains of Metarhizium anisopliae were regarded as the research object, the indoor toxicity effect of 19 strains of Metarhizium×sp on 2th instar larva of Spodoptera litura and Myzus persicae were determined. And a high virulent strain was screened from them and mixed with four kinds of pesticides respectively. Ultimately, the control effect of highest virulence mixture on Spodoptera litura and Myzus persicae were determined by toxicity test and potted plant test. The purpose evaluated the control function and its application potential of Spodoptera litura, Myzus persicae strain.The main results were as follows: 1. The pathogenicity size of 19 strains of Metarhizium×sp which the concentration of spore suspension at 1.00 x 109 conidia / m L for 2th instar larva of Spodoptera litura was determined by quantitative and spray method and dipping immersion. The results showed that there existed certain differences between different strains for 2th instar larva of Spodoptera litura of pathogenicity. The results of quantitative and spray method showed that the average stiff worms' rate of these strains on 2th instar larva of Spodoptera litura was between 0 to 37.78%. And the average stiff worms' rate size of strains on 2th instar larva of Spodoptera litura followed by M09>1245>F985>QC>M19>M20> SXB>3297>M28> M30> [GNJ44, TS22]> [M42, M43, M55, TS24]> [M25, M40, GNJ49]. The results of the dipping immersion method showed that the average stiff worms' rate of these strains on 2th instar larva of Spodoptera litura was 2.22% to 66.67%. And the average stiff worms' rate size of strains on 2th instar larva of Spodoptera litura followed by 1245>F985>M09>3297>M25>[M43,QC]>M19>M28>M20>M55>SXB> TS22 > GNJ44 > M42 > TS24 > GNJ49 > [M30, M40]. The stronger pathogenicity of Metarhizium anisopliae strains 1245, M09, F985 were selected Which was based on an overall consideration of various factors including strains preservation period, colony growth rate, sporulation and spore germination and so on. 2. The pathogenicity size of 19 strains of Metarhizium×sp which the concentration of spore suspension at 1.00 x 109 conidia / m L for Myzus persicae was determined by quantitative and spray method. The results showed that the pathogenicity of different strains for Myzus persicae had distinct difference which ranged from weak to strong. The stiff worms' rate of these strains on Myzus persicae was between 0 to 100.00%. And the average stiff worms' rate size of strains on Myzus persicae followed by M09> [F985, M43]> M28>M55>M20>QC>1245>GNJ44>SXB>3297>M25>M19>TS22> TS24>M40> M42> [M30, GNJ49]. The stronger pathogenicity of Metarhizium anisopliae strains M09, F985,1245 were selected which was based on an overall consideration of various factors including strains preservation period, colony growth rate, sporulation and spore germination and so on. 3. The insecticidal activity of 3 strains of Metarhizium×sp early screened and made into different concentration for 2th instar larva of Spodoptera litura and Myzus persicae were determined. Through the pathogenicity determination of these strains under the same concentration and different concentrations, the strain M09 of Metarhizium anisopliae was screened out with high toxicity and good traits. For the 2th instar larva of Spodoptera litura, Its average stiff worms' rate were 47.78% and 8.89%, when the concentration of spore suspension at 1.00 x 109 conidia / m L and 1.00 x 103 conidia / m L, respectively. Besides, the LC50 was 1.06 x109 conidia / m L. For Myzus persicae, Its average stiff worms' rate were 100.00% and 46.67%, when the concentration of spore suspensionat 1.00 x 109 conidia / m L and 1.00 x 103 conidia / m L, respectively. Besides, the LC50 was 4.80×103 conidia / m L. 4. That the toxicity of strain M09 with the concentration of 1.06 x109 conidia/m L mixed with Chlorine worm benzamide, Deltamethrin, Azadirachtin, Lansiumamide B at the dose of 10.00?g/m L, 1.33?g/m L, 3.33?g/m L, 200?g/m L was determined for 2th instar larva of Spodoptera litura. And that the toxicity of strain M09 with the concentration of 4.80×103 conidia/m Lmixed with Chlorine worm benzamide, Deltamethrin, Azadirachtin, Lansiumamide B at the dose of 10.00?g/m L, 1.33?g/m L, 3.33?g/m L, and 200?g/m L was determined for Myzus persicae. The results showed that both the mixture pathogenicity was better than that of pesticides single dose.and the strain M09 mixed with chlorine worm benzamideas had better and synergistic control effect. The virulence of synergy index of the mixture that had better synergistic effect on 2th instar larva Spodoptera litura and Myzus persicae is 22.95 and 20.06 respectively. 5. The result of potted experiment showed that the toxicity of strain M09 with the concentration of 1.06 x109 conidia/m L mixed with Chlorine worm benzamide at the dose of 10.00?g/m L had a better effect than the single dose treatment for 2th instar larva of Spodoptera litura. And that the toxicity of strain M09 with the concentration of 4.80×103 conidia/m L mixed with Chlorine worm benzamide at the dose of 10.00?g/m L also had a better effect than the single dose treatment for Myzus persicae. After 5d treatment, the control effect reached at 89.28% on 2th instar larva of Spodoptera litura. After 3d treatment, the control effect reached at 89.28% on Myzus persicae. |
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