The Joint Toxicity of Different Temperature Coefficient Insecticides on Apolygus lucorum (Hemiptera: Miridae)

Authors: LIN, JIA - Hebei Academy Of Agriculture & Forestry; Reall, Tamra; AN, JINGJIE - Hebei Academy Of Agriculture & Forestry; GAO, ZHANLIN - Hebei Academy Of Agriculture & Forestry; DANG, ZHIHONG - Hebei Academy Of Agriculture & Forestry; PAN, WENLIANG - Hebei Academy Of Agriculture & Forestry; LI, YAOFA - Hebei Academy Of Agriculture & Forestry

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/27/2016
Publication Date: 2/14/2016
Citation: Lin, J., Lincoln, T.R., An, J., Gao, Z., Dang, Z., Pan, W., Li, Y. 2016. The Joint Toxicity of Different Temperature Coefficient Insecticides on Apolygus lucorum (Hemiptera: Miridae). Journal of Economic Entomology. doi:10.1093/jee/tow082.

Interpretive Summary: Insecticides are essential tools in insect pest management, however, environmental temperatures seriously influence insecticide efficacy, with some more effective at higher temperatures and others at lower temperatures. Insecticides are frequently mixed before field application, which is problematic because the mixtures can decrease the overall insecticidal efficacy. We addressed this issue by determining the efficacy of selected insecticide mixtures at different temperatures. Our data show that some insecticide mixtures are highly effective in controlling insect pests at specific temperatures, while other mixtures are not. This information creates a very useful decision tool that can be easily understood and used by crop managers to optimize insect pest control by selecting highly efficacious insecticide mixtures for field application.

Technical Abstract: The effect of temperature on the co-toxicity coefficients (CTC) value was used to evaluate mixture efficacy of different temperature coefficient chemicals from 15°C to 35°C by exposing third-instar Apolygus lucorum (Meyer-Dür) to dip-treated asparagus bean pods. The results indicated the joint action of similar temperature coefficient insecticide (TCI) types were unaffected by temperature. This means that even when temperatures change, the mixture ratios of the highest CTC values remained the same, and the effect of temperature on the joint action of same TCI types was only on the CTC values. However, the effect of temperature was variable when considering the joint action of different TCI types. The effect of temperature on the joint action of both strong positive and strong negative TCI types was clear, and the highest CTC values of mixture ratios changed with temperature regularly. When comparing the influence of temperature between strong/slight positive/negative insecticides, the results indicated a greater influence of the strong TCI. Paradoxically, the highest CTC value of the imidacloprid and methomyl mixture did not change with temperature changes consistently, even with the variance of imidacloprid ratios, a strong TCI. These results will guide pest managers to choose the most effective insecticide mixtures for A. lucorum control under given environmental conditions.