Investigation of diflovidazin and fenpropathrin on two-spotted spider mite, Tetranychus urticae Koch, 1836 (Acari: Tetranychidae): population and interaction study

Abstract

Tetranychus urticae is one of the most important pests of agricultural crops around the world. This research investigated the lethal effects of diflovidazin and fenpropathrin on different life stages of two-spotted spider mites, the interaction of binary mixture of these two compounds, and sublethal effects of diflovidazin on the deutonymphs under laboratory conditions. The Potter spray tower was used for the bioassay of acaricides on different life stages of T. urticae. The results showed that diflovidazin was effective on different developmental stages excluding female’s adults. Also, fenpropathrin showed toxicity on all life stages except eggs. LC50 value and combination index (CI) of their mixture against deutonymph were 4.85 mg l-1 and 0.5 mg 1-1, respectively, which revealed a synergistic effect on T. urticae. Sublethal effects of LC30 concentration of diflovidazin were evaluated on life table parameters of T. urticae. The value of the intrinsic rate of increase (r), the finite rate of increase (λ), and the net reproductive rate (R0) significantly decreased in treated mites in comparison to control. These results suggested that diflovidazin could have significant roles in the control of T. urticae due to negative effect on population parameters as well as synergistic effect of binary mixtures of this acaricide with fenpropathrin.

Keywords

• two-spotted spider mite
• life table
• mixture of pesticides
• interaction