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对水稻重要害虫褐飞虱Nilaparvata lugens目前市场上尚无一种理想的微生物杀虫剂。昆虫病原真菌具有从体壁侵入的能力因而对刺吸性害虫的防治具有优势。为此,本研究选用不同原寄主和来源地的3种昆虫病原真菌(金龟子绿僵菌Metarhizium anisopliae、黄绿绿僵菌Metarhizium flavoviride和球孢白僵菌Beauveria bassiana)的12个不同菌株,以1100孢子/mm2孢子悬浮液进行室内毒力测定。结果表明:在参试的不同菌种12个菌株中,黄绿绿僵菌Mf82菌株对褐飞虱成虫致病力最高,10d累计校正死亡率为83.5%,致死中时(LT50)为4.6d。其不同浓度孢子液对褐飞虱3个发育阶段有不同程度的致病力,毒力大小顺序为成虫>高龄若虫>低龄若虫。黄绿绿僵菌孢子液对各处理稻株褐飞虱产卵痕部位、卵粒均有侵染作用,10d侵染率分别为66.7%和51.2%,卵龄越低,侵染效果越好,卵龄为0.5d时侵染率最高。本研究表明黄绿绿僵菌Mf82菌株对褐飞虱成虫、若虫和卵均有较强的致病性,是一株极具应用潜力的生防真菌。
Nilaparvata lugens, a major rice pest, Nilaparvata lugens There is currently no ideal microbial pesticide on the market. Entomopathogenic fungi have the ability to invade from the body wall and thus have an advantage over the control of spiked pests. In this study, 12 different strains of 3 kinds of entomopathogenic fungi Metarhizium anisopliae (Metarhizium flavoviride and Beauveria bassiana) from different original host and origin were selected for the study. / mm2 spore suspension for indoor toxicity determination. The results showed that Mf82 was the most pathogenic to the brown planthopper (BPH) adults, with a cumulative adjusted mortality of 83.5% after 10 days and a median lethal dose (LT50) of 4.6 days among the 12 strains tested. The different concentrations of spore liquid had different degrees of virulence on the three developmental stages of N. lugens, and the order of their virulence was adult> nymph> young nymphs. The spore solution of M. anisopliae could infect the oviposition sites and eggs of the brown planthopper in the rice plants. The infection rates on the 10th day were 66.7% and 51.2%, respectively. The lower the egg age was, the better the infection was. The infection rate was the highest at 0.5d. The present study shows that Mf82 strain of Metarhizium anisopliae has strong pathogenicity to adult, nymphs and eggs of BPH, and it is a potential biocontrol fungus.