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Issue:ISSN 2095-1353
           CN 11-6020/Q
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Your Position :Home->Past Journals Catalog->2022年59 No.5

Ovicidal effect of primary insecticides on Cnaphalocrocis medinalis in paddy field
Author of the article:GUO Jia-Wen;HE Xiao-Chan; CHENG Yi-Sha; AUNG Thura; LU Yan-Hui;LI Wen-Qiang;XU Hong-Xing;HUNG Jian-L
Author's Workplace:State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China; Jinhua Academy of Agricultural Sciences, Jinhua 321000, China
Key Words:Cnaphalocrocis medinalis; egg development; insecticides; toxicity; egg dipping method
Abstract:
[Objectives]  To clarify the ovicidal effect of primary insecticides on the rice leaf folder, Cnaphalocrocis medinalis, in paddy fields and thereby provide a scientific basis for the safe and efficient control of this pest. [Methods]  The toxicity of eight primary insecticides (chlorantraniliprole, abamectin, chlorpyrifos, indoxacarb, imidacloprid, pymetrozine, thiamethoxam and thiazide) commonly used in rice fields was determined in a laboratory. The toxicity of these insecticides on C. medinalis eggs of different ages, and their effects on the survival of newly hatched larvae, were measured, and the effect of insecticides on the subsequent development of eggs was observed. [Results]  Chlorantraniliprole had a corrected egg hatching inhibition rate of 10.42%-100.00%, and had stronger ovicidal activity than abamectin, chlorpyrifos or indoxacarb. Chlorantraniliprole was most toxic to 1 and 3-day-old (LC50 2.123 and 1.904 mg/L, respectively). Treatment soon after eggs are laid can cause them to fail to develop normally and the age at which eggs were treated significantly affected the mortality of newly hatched larvae, indicating that it is better to treat eggs as soon as possible. The corrected hatching inhibition rate for imidacloprid ranged from 20.00% and 91.67%. Imidacloprid had stronger ovicidal effect than pymetrozine and thiamethoxam. Thiazide had the least ovicidal effect. Treating 3 to 4-day-old eggs with imidacloprid resulted in larvae developing normally but inhibited hatching. Treating eggs at this time achieved both the best ovicidal effect and the highest mortality among newly hatched larvae, indicating that imidacloprid should be applied 2 days after eggs have been laid. [Conclusion]  Of the eight insecticides, chlorantraniliprole had the strongest ovicidal activity to the rice leaf folder, and its ovicidal effect was higher when applied to newly laid eggs. Imidacloprid and thiamethoxam had a lower ovicidal effect, but, of these imidacloprid had the stronger effect and can achieve good results when applied to eggs 3 to 4 days after laying.
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