M. Isabel Ahumada1, and Rodrigo A. Chorbadjian1*
Cyantraniliprole has a broader insecticidal spectrum than the previously developed diamides. Because cyantraniliprole also targets hemipteran pests, it could provide an alternative to neonicotinoids like imidacloprid. However, there is limited information concerning how its broad-spectrum activity affects biological control agents. Toxicity of cyantraniliprole and imidacloprid to green peach aphid (Myzus persicae [Sulzer, 1776]), cabbage aphid (Brevicoryne brassicae [Linnaeus, 1758]) and greenhouse whitefly (Trialeurodes vaporariorum [Westwood, 1856]) nymphs was determined using both systemic and direct spray exposure. In addition, the direct spray activity of cyantraniliprole and imidacloprid on larvae of green lacewing, Chrysoperla defreitasi Brooks, 1994, was studied. Estimated LC50 values indicated that M. persicae, B. brassicae and T. vaporariorum were more susceptible to the systemic exposure to cyantraniliprole than to direct spray (0.148 vs. 24.284, 0.004 vs. 11.004, and 0.268 vs. 30.832 mg L-1, respectively). Similarly, susceptibility of M. persicae, B. brassicae and T. vaporariorum to imidacloprid was more pronounced when exposed systemically than through direct contact (0.018 vs. 1.149, 0.006 vs. 0.514, and 0.249 vs. 6.419 mg L-1, respectively). Hence, the population of B. brassicae was40-fold more susceptible to cyantraniliprole than M. persicae when exposed to its systemic activity, and 2.2-fold more susceptible to cyantraniliprole’s direct spray activity than M. persicae. Interestingly, T. vaporariorum was less susceptible to the direct spray activities of cyantraniliprole compared to that of imidacloprid by 4.8-fold, but both insecticides were equally toxic for this species after systemic exposure. Crysoperla larvae were less susceptible to direct exposure to cyantranaliprole in comparison with imidacloprid (640.295 vs. 26.974 mg L-1). In comparison to imidacloprid, direct spray insecticidal activity of cyantraniliprole was less toxic to these hemipteran pests and to chrysoperla larvae. This suggests that the selectivity of cyantraniliprole towards C. defreitasi, as measured by direct spray only, could decline if its concentration is increased to target these hemipteran pests by foliar sprays.
Key words: Insecticide, lethal-concentration, Hemiptera, Neuroptera, selectivity.
1Pontificia Universidad Católica de Chile, Facultad de Agronomía e Ingeniería Forestal, Vicuña Mackenna 4860, Santiago, Chile.
*Corresponding author (firstname.lastname@example.org).