Acta Entomologica Sinica (2008) 51, 216-221

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Jiao Chen, Dun-Lun Song, Hui-Xian Li, Hui Jiang, Xiao-Jun Wang, Rong-Hua Lin and Xi- Wu Gao (2008)
[Effects of penetration enhancers on the toxicity of beta-cypermethrin and epicuticle ultrastructure of three lepidopterous insects]
Acta Entomologica Sinica 51 (2), 216-221
Abstract: The effects of penetration enhancers, azone, thiazone and N-methyl-2-ketopyrrolidine, on the toxicity of beta- cypermethrin were investigated by bioassay in Spodoptera exigua (Hübner), Plutella xylostella (L.) and Helicoverpa armigera (Hübner), and their effects on epicuticle ultrastructure of the tested insects were observed by scanning electron microscope. The results showed that the LD50 value of beta- cypermethrin with 3.0% N-methyl-2-ketopyrrolidine was 0.0074 µg/larva in P. xylostella. Beta-cypermethrin could be synergisted by N-methyl-2-ketopyrrolidine (the coefficient of toxicity was 2.0) in P. xylostella but not in S. exigua and H. armigera. However, the toxicity of beta-cypermethrin could not be enhanced by azone and thiazone in P. xylostella, S. exigua and H. armigera. The observations by scanning electron microscope showed that the cement layer of the epicuticle in the fourth instar larvae of S. exigua disappeared after treatment with penetration enhancers. The epicuticle ultrastructure in the fourth instar larvae of P. xylostella treated by N-methyl-2-ketopyrrolidine was not different from the control group, but the cement layer of epicuticle disappeared in the P. xylostella larvae treated by azone. The results suggested that the diversification of the cement layer of epicuticle was not the synergistic mechanism of penetration enhancers to beta-cypermethrin in the three lepidopterous insects.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
(original language: Chinese)
Database assignments for author(s): Xi-Wu Gao, Dun-Lun Song

Research topic(s) for pests/diseases/weeds:
control - general

Pest and/or beneficial records:

Beneficial Pest/Disease/Weed Crop/Product Country Quarant.

Helicoverpa armigera
Plutella xylostella
Spodoptera exigua