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Common control strategies to manage stored product pests are mainly based on the use of synthetic insecticides and fumigants. Consumer’s demand for pesticide-free food, and the increasing resistance of pests to traditional insecticides, dictate the need to evaluate alternative control methods. For this purpose, many sustainable techniques have been tested for the control of stored product pests. Among them, Citrus essential oils can represent a valid alternative to synthetic insecticides. The effects of Sweet Orange essential oil (EO) nanoemulsion applied as cold aerosol were evaluated against adults of Tribolium confusum du Val (Coleoptera: Tenebrionidae) and Cryptolestes ferrugineus Stephens (Coleoptera: Cucujidae). Both chemical and physical characterization of the EO-based formulation was carried out. The developed formulation had an average size belonging to the nanometer scale and a low polydispersity index. The relatively high zeta potential value confirms the stability over time of the developed formulation. The efficacy of the tested formulation showed a dose-dependent response and the cumulated mortality of the exposed insects increaseduntil 24h of exposure for C. ferrugineus and until 120h for T. confusum. The tested formulation was more effective against T. confusum adults (LD50= 86.30 ppm) than C. ferrugineus ones (LD50= 36.79 ppm). The results of this study coupled with the large availability at reasonable costs of Sweet orange EO, are promising for the potential development of new tools against stored product pests.

The role of selective new generation bioisecticides, beside their effectiveness against key pests, relies on their safety to beneficial arthropods. Spinetoram, a semi-synthetic analogue of the microbial-derived bioinsecticide spinosad is registered worldwide for application in numerous crops, but assessment of its ecotoxicological risk to beneficial arthropods has scarcely been documented. Moreover, this is the first report on toxic effects of spinetoram on a pest, the greenhouse whitefly Trialeurodes vaporariorum Westwood (Hemiptera: Aleyrodidae), and/or its successful biocontrol agent, the parasitoid Encarsia formosa Gahan (Hymenoptera: Aphelinidae). Under laboratory conditions, we assessed the acute toxicity of spinetoram insecticide (25% a.i.) to adults, nymphs and eggs of the greenhouse whitefly, as well as to parasitoid adults and pupae. In all concentration-response bioassays, the spinetoram insecticide was applied to tobacco leaves settled onto 1% agar layer in ventilated Petri dishes using a Potter spray tower. The parameters of spinetoram acute toxicity to adults of both the pest and the parasitoid were evaluated in residual contact bioassays, while whitefly eggs and nymphs, and parasitoid pupae were topically treated with a series of spinetoram concentrations, covering a range of 10-90% mortality. Lethal spinetoram effects on the parasitoid E. formosa were assessed through selectivity ratio (SR) estimations, showing the ratios beetween median lethal concentrations (LC50s) estimated for the parasitoid, and LC50s estimated for the pest. The following LC50 values were obtained: 4.593, 15.027 and 11.73 mg A.I./l for whitefly adults, nymphs and eggs, respectively, and 0.686 and 1.715 mg A.I./l for parasitoid adults and pupae, respectively. The calculated SR estimations were below 1, indicating that spinetoram insecticide is non-selective to both tested stages of the parasitoid E. formosa. A more detailed understanding of spinetoram impact on E. formosa in whitefly integrated management requires further evaluation of sublethal effects and greenhouse trials, with an emphasis on population-level responses.