Improving the control efficiency of the novel green botanical pesticide toosendanin by optimizing physicochemical properties

While TSN (toosendanin) has good control efficacy against agricultural pests, rapid degradation hinders its widespread application in the field.

In this study, through the screening and application of various green additives, a novel and environment-friendly TSN 0.5% emulsifiable concentrate (EC) formulation with a long efficacy period and high efficiency against pests was developed using methyl oleate (MO) and azone as adjuvants. The MO-EC formulation exhibited improving permeability, wettability, spreading, and stickiness, along with higher bioactivity and a longer efficacy period, compared with the Xylene-EC formulation. The bioassay results showed that the LC₅₀ values of the MO-EC formulation against Aphis citricola van der Goot, Mythimna separata, and Plutella xylostella (58.11, 85.86, and 66.93 mg L^-1, respectively) were lower than those of the Xylene-EC sample (82.66, 148.01, and 109.03 mg L^-1, respectively) and the TSN soluble liquid (311.22, 275.93, and 230.93 mg L^-1, respectively). Compared with the Xylene-EC formulation and TSN soluble liquid, the MO-EC formulation displayed a higher and longer residual control of approximately 91.32%, 85.71%, and 85.43% against A. citricola van der Goot, M. separata, and P. xylostella, respectively, at 10 days post-treatment with a dosage of 5.25 g A.I hm^-2. Compared with the Xylene-EC formulation, the higher bioactivity and longer efficacy period of MO-EC formulation are attributed to optimized physicochemical properties.

The MO-EC formulation possesses the potential to serve as a novel and alternative chemical pesticide for sustainable agricultural pest control. © 2025 Society of Chemical Industry.