Toxicity of Agricultural Adjuvant Cytogate Oil and the Insecticide Pymetrozine to the Cabbage Aphid, Brevicoryne brassicae L. (Hemiptera: Aphididae) and its Parasitoid, Diaeretiella rapae M. (Hymenoptera: Aphidiidae)

Toxicity of the agricultural adjuvant Cytogate and Pymetrozine to the cabbage aphid, Brevicoryne brassicae L. (Hemiptera: Aphididae) was evaluated using leaf dipping bioassays under laboratory conditions. Residual toxicity of these compounds to the parasitoid Diaeretiella rapae McIntosh (Hymenoptera: Aphidiidae), at recommended field rate, was estimated using IOBC/WPRS protocols. In aphid's bioassay, LC50 values of Pymetrozine and Cytogate were 886 and 2788 ppm, respectively. For determination of the interaction between these compounds, the LC25 values of Pymetrozine and Cytogate were determined and mixture of both compounds was applied at concentrations of its LC25 rate. The mixture caused 65.48 +/- 0.02 (%) mortality among cabbage aphid adults. The mortality rate resulted from the mixture was greater than that of Pymetrozine at the LC50 concentration. Hence, a noticeable synergistic effect was observed. Survival of D. rapae was reduced by the residual effect of Pymetrozine. Cytogate alone and in combination with Pymetrozine, were harmless and slightly harmful to mummies and adults of the parasitoid. It was concluded that due to the cheap price of Cytogate, compatibility with parasitoid, synergistic effect on Pymetrozine, mixture application of these compounds could be recommended in cabbage aphid control programs.