The virulence of 5 Metarhizium anisopliae strains against Brontispa longissima in different development stages were determined by spraying.The results showed that various strains of M.anisopliae had certain virulence against B.longissima after inoculation with (1±0.5)x107 spore·mL-1 for 10 d.Compared various strains,Ma1775 strain exhibited the most effective virulence against B.longissima.Mter treatment,the Ma1775 strain caused a cumulative corrected morality of (67.96±3.66)％,the cadaver rate of (60.59±1.31)％ and the median lethal time (LT50) of (7.11±0.52) d in adults.For 5 instar larvae,the corrected mortality and cadaver rate were (78.53±2.73)％ and (73.55±3.22)％,with LT50(5.77±0.38) d.The corrected mortality and cadaver rate were (82.59±2.48)％ and (77.86±3.44)％,and LT50 was (5.80±0.14) d for 4 instar larvae.The corrected mortality and cadaver rate were (73.46±4.60)％ and (69.50±3.87)％ for 2～3 instar larvae,with LT50(6.49±0.12) d.The median lethal concentration (LC5o) of Ma1775 strain at each development stage in 6 d were 3.52×10s,7.13×107,2.48× 107,7.69×107 spore· mL-1,respectively.By employing a time-dose-mortality model to estimate parameters of time and dose,the Ma1775 strain had a high lethal effect on B.longissima during 3～7 d after treatment.Thus,the Ma1775 strain has been proved to be a great potential application in biological control to B.longissima.
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维普
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