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Comparison of the toxicity of dimethoate and cypermethrin in the laboratory and the field when applying the same bioassay
Author(s) -
Akkerhuis Gerard A.J.M. Jagersop,
Damgaard Christian,
Kjær Christian,
Elmegaard Niels
Publication year - 1999
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.5620181036
Subject(s) - dimethoate , bioassay , toxicant , toxicology , cypermethrin , biology , pesticide , larva , toxicity , ecology , chemistry , organic chemistry
Abstract The present paper studies the relationship between laboratory‐ and field—based survival data of beetle larvae sprayed with either dimethoate or cypermethrin. The comparison for dimethoate was based on an earlier constructed pesticide—effect model derived from greenhouse data. To predict field effects, the model was supplied with field data for temperatures, the insecticide concentrations on the plants, and the control mortality rate of the beetles. The same model structure was unable to predict greenhouse mortality from cypermethrin treatment, for which reason the differences between laboratory and field for this compound are discussed on the basis of direct observations. For best comparison, the same bioassay method was used in both the greenhouse and the field in the present study. Tests were based on Gastrophysa polygoni larvae dwelling on the undersides of leaves of Fallopia convolvulus plants. Dietary uptake was regarded as the main source of exposure. The simulation results for dimethoate underestimated the field mortality even after accounting for the higher control mortality in the field in the model. It was shown that an additional increase of the toxicant—induced death rate by more than a factor of five was required for the model to fit the field data. This indicated a relatively severe impact of dimethoate under field conditions. For cypermethrin, the effects in the field increased with time, pointing at increasing exposure of and/or effects on the larvae. Contributions of the present results toward the bridging of the gap between laboratory and field are discussed.