绿僵菌及其与dsRNA混合使用对褐飞虱的防治效果

褐飞虱Nilaparvata lugens Stl是我国重要的迁飞性水稻害虫,本文研究了金龟子绿僵菌Metarhizium anisopliae及其与dsRNA混合使用对褐飞虱的防治效果。绿僵菌悬浮液1.6×108孢子/m L至8×106孢子/m L对褐飞虱2龄、4龄和成虫进行喷药,发现1.6×107孢子/m L对各个虫态虫龄均有良好致死效果,并且成虫和4龄若虫均好于2龄若虫。在交配行为上来看,绿僵菌处理过的褐飞虱成虫活跃度非常低,从配对开始一直到交配结束的各个阶段都受到明显影响,处理组3 h的交配率只有3.70%,而对照组的交配率为24.44%。还把褐飞虱几丁质合成酶基因A的dsRNA与绿僵菌混合使用防治褐飞虱2龄和4龄若虫,结果表明0.5μg/μL ds CHSA与绿僵菌混合使用的防治效果最好,2龄若虫的死亡率为89.63%,4龄若虫的死亡率达到93.94%。而0.2μg/μL ds CHSA与绿僵菌的混合,对2龄和4龄若虫的致死率为65.56%-76.52%。研究结果为褐飞虱的生物防治提供了新的思路。

Control effect of Metarhizium anisopliae and its mixture with dsRNA on the brown planthopper

The brown planthopper ( BPH) Nilaparvata lugens St?l is an important migratory insect pest of rice. This paper studied the control effect of Metarhizium anisopliae on the brown planthopper and its application mixed with dsRNA of chitin synthase gene A ( CHSA) . M. anisopliae suspension was 1. 6 × 108 spores/mL to 8 × 106 spores/mL and then sprayed onto BPH nymphs ( second instars and fourth instars) and adults, the results showed that 1. 6 × 107 spores/mL M. anisopliae resulted in good mortality rates for both nymphs and adults, and that control effect for adults and the fourth instar nymphs was better than that for the second instar nymphs. In the mating behavior experiments, activity of the BPH adults treated with M. anisopliae (1. 6 × 107 spores/mL) was very low, all stages from pairing to success of mating were affected significantly by the spraying. During 3 h period, the mating rate in the treated group was only 3. 70% whereas it was 24. 44% in the control group. When mixed M. anisopliae with dsRNA of BPH chitin synthase gene A, better control effects were achieved. When the concentration of dsRNA was 0. 5 μg/μL dsCHSA, the mortality rate of the second and fourth instars was 89. 63% and 93. 94%, respectively;when the concentration of dsRNA was 0. 2μg/μL dsCHSA, the mortality rate of the second and fourth instars was 65. 56% -76. 52%. The results gained may provide novel clue for better control of the brown planthopper.