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Chinese Journal Of Biological Control ›› 2019, Vol. 35 ›› Issue (5): 721-728.DOI: 10.16409/j.cnki.2095-039x.2019.05.028

• Biological Control of Spodoptera frugiperda Previous Articles     Next Articles

Screening for Bacillus thuringiensis Strains with High Toxicity against Spodoptera frugiperda

LIU Huamei1, HU Xiao1, WANG Yinglong2, YANG Puyun3, SHU Changlong2, ZHU Xiaoming3, ZHANG Jie2, SUN Gangzhong1, ZHANG Xiaoming1, LI Qing1   

  1. 1. Wuhan Kernel Bio-tech Co., Ltd, Wuhan 430074, China;
    2. State Key Laboratory for Biology of Plant Diseases and Insect Pests/Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China;
    3. National Agro-Tech Extension and Service Center, Beijing 100125, China
  • Received:2019-08-21 Online:2019-10-08 Published:2019-10-26

Abstract: To screen Bt strains with high virulence against Spodoptera frugiperda is crucial for the development of green and efficient IPM of S. frugiperda. In this study, nine Bt strains with high toxicity to Noctuidae, isolated by our company, were tested for their virulence against S. frugiperda in laboratory, and analyzed the insecticidal genes. Three of the highest virulent strains were further tested in field trial for their control efficacies against S. frugiperda. The results indicated that nine Bt strains showed prominent insecticidal activity against neonate of S. frugiperda at 7 days post treatment. The LC50 ranged from 0.07 to 3.38 μg/g. The three highest virulent strains were KN50, KN11 and KNR8, with LC50 of 0.07, 0.23 and 0.43 μg/g, respectively, showing very remarkable efficacy. Insecticidal gene analysis results demonstrated that six highly virulent Bt strains contained the same four insecticidal genes-vip3Aa, cry2Ab, cry1Ac and cry1Ia. Field trial results showed that the control efficacies of KN50, KN11 and KNR8 with 32000 IU/mg were significantly different, but were consistent with laboratory results. KN50 showed the highest insecticidal efficacy at 7 days post treatment, which was 86.09% and 95.22% for 200 g/667 m2 and 400 g/667 m2, respectively, against the first to third instar larvae, and 72.61% and 86.59% against larval populations of mixed instars. Therefore, the KN50, KN11 and KNR8 strains represent candidates for new product development to replace chemical pesticides and achieve green control S. frugiperdar.

Key words: Spodoptera frugiperda, Bacillus thuringiensis, bioassay, insecticidal gene analysis, field control efficacy

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