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为了寻找褐飞虱Nilaparvata lugens生物防治的新途径,用新分离出的黄绿绿僵菌Metarhiziumflavoviride(Mf82)菌株与实验室保存的黄绿绿僵菌、金龟子绿僵菌和球孢白僵菌3种菌种9个菌株作对比,测定了它们对褐飞虱成虫的毒力。结果表明:Mf82菌株对褐飞虱成虫的毒力最高,以1.0×108个孢子/mL的孢子液喷雾接种到褐飞虱成虫体表上,累积死亡率高达81.7%,LT50为4.6d,致病效果显著高于其他受测菌株。在此基础上研制了黄绿绿僵菌悬乳剂,并研究了其对褐飞虱的致病力。结果表明:随着黄绿绿僵菌浓度的增加,褐飞虱的累计死亡率增加,在浓度为1,048个孢子/mm2时,累计死亡率达到85.0%。利用时间-剂量-死亡率模型对数据进行处理,所建模型均顺利通过Hosmer-Lemeshow拟合异质性检验,表明模型拟合良好,并由模型估计出了该剂型对褐飞虱的致死剂量与致死时间。在接种后第7天和第9天,LC50值分别为2.1×103、9.9×102个孢子/mm2,LC90分别为7.8×104、3.7×104个孢子/mm2。黄绿绿僵菌悬乳剂对褐飞虱的致死时间与对数剂量相关,供试菌剂LT50值随着对数剂量的增加而递减,对数剂量由7.0增加到8.0时,LT50由8.9d降为5.7d。可见该黄绿绿僵菌悬乳剂对褐飞虱具有较强的毒力,在褐飞虱生物防治中具有广阔的应用前景。
In order to find out a new way of biological control of Nilaparvata lugens, the newly isolated strains of Metarhizium flaviviride (Mf82) and Metarhizium anisopliae, M. anisopliae and Beauveria bassiana The strains were compared to determine their virulence to BPH adults. The results showed that the Mf82 strain had the highest virulence to BPH adults. Spores of 1.0 × 108 spores / mL were inoculated on the body surface of BPH adults with cumulative fatality rate of 81.7% and LT50 of 4.6 d, with significantly higher pathogenicity In other tested strains. On the basis of this, we developed the virulent emulsion of Metarhizium anisopliae and studied its virulence to BPH. The results showed that with the increase of Metarhizium anisopliae, the cumulative mortality of N. lugens increased, reaching a cumulative mortality rate of 85.0% at a concentration of 1,048 spores / mm2. The time-dose-mortality model was used to process the data, and the models were all successfully passed the Hosmer-Lemeshow fitting heterogeneity test, indicating that the model was well fitted and the lethal dose and lethality of the dosage form to the BPH were estimated time. On day 7 and day 9 after inoculation, the LC50 values were 2.1 × 103 and 9 × 102 spores / mm2, respectively, and the LC90 values were 7.8 × 104 and 3.7 × 104 spores / mm2, respectively. The lethal time of M. anisopliae emulsion against BPH was correlated with the logarithmic dose. The LT50 value of the tested bacterial agent decreased with increasing logarithmic dose. When the logarithmic dose increased from 7.0 to 8.0, the LT50 decreased from 8.9d to 5.7 d. It can be seen that the M. avium suspension emulsion has strong virulence to N. lugens and has broad application prospects in the biological control of N. lugens.