• The Korean Journal of Pesticide Science
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• v.6 no.3
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• pp.193-201
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• 2002

The effects of 24 ionic and nonionic surfactants on paraquat (1, 1' -dimethyl-4 4'-bipyridinium) efficacy were investigated with several annual plant species under greenhouse conditions. The paraquat efficacy was decreased or even lost when treated with the anionic surfactants tested. However, the efficacy of paraquat was significantly increased by 7 nonionic surfactants such as sorbitan palmitate, sorbitan stearate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene stearyl ether, polyoxyethylene laurylamine ether, and polyoxyethylene stearylamine ether. Among these tested surfactants, 0.08% of polyoxyethylene laurylamine ether most significantly increased the paraquat activity, and the $GR_{50}$ value of paraquat with polyoxyethylene laurylamine ether was 1.6 times lower than the $GR_{50}$ value without polyoxyethylene laurylamine ether. In in vitro experiments, cellular leakage and chlorophyll contents between the application with and without polyoxyethylene laurylamine ether did not show significant changes. The absorption rate of $^{14}C$ paraquat in the treatment with polyoxyethylene laurylamine ether showed an absorption rate of 1.6 times higher than without surfactant. These results suggest that using compatible surfactants would increase the paraquat efficacy, and this increasing are due to improved absorption rate with the surfactant.