Effects of different surfactants on the toxicity of beta-cyfluthrin EW to Carposina sasakii Matsumura (Lepidoptera: Carposinidae)
Author of the article:ZHANG Peng-Jiu** GAO Yue SHI Gao-Chuan GUO Rui-Feng LIU hong-Fang FENG Yun-Tao ZHANG Run-Xiang
Author's Workplace：Shanxi Key Laboratory of Integrated Pest Management in Agriculture, Institute of Plant Protection, Shanxi Academy of Agricultural Sciences, Taiyuan 030031, China
Key Words：beta-cyfluthrin EW, surfactant, Carposina sasakii, surface tension
Abstract： [Objective] To develop a new, more environmentally friendly pesticide for the control of Carposina sasakii Matsumura. [Methods] The thermal stability, particle size, surface tension and contact angle of four types of 2.5% beta-cyfluthrin EW were investigated with different surfactants, and the effectiveness of different formulations of this pesticide were tested on C. sasakii in an apple orchard. [Results] Decomposition rates of the four types of beta-cyfluthrin EW (1#, 2#, 3#, 4#) with different surfactants (FMEE、IS-TEO、Ningru34、Nongru700) were all < 5% after thermal storage, which complies with the national standard for thermal storage stability. D50 was in the range of 0.85-2.12 µm, which is the ideal range for EW. The surface tension of dilutions was 43.32-51.89 mN/m. The contact angle of dilutions on apple leaves was 47.45 o to 74.38o, which is considerably lower than surface tension of water, suggesting that the pesticide solution should have excellent adhesion to the apple leaf surface. A 2 000-3 000 part dilution of EW achieved 84.62%-100% mortality of C. sasakii. Compared to 4.5% beta-cyfluthrin EC, there was no significant difference in mortality between the four EW formulations tested. Compared to EC, EW contains 70% less organic solvents. [Conclusion] Based on factors such as thermal stability, particle size, surface tension, contact angle, control effect and pesticide reduction, 3# beta-cyfluthrin EW is recommended for the control of C. sasakii in apple orchards.