Pesticide risk assessments are usually based on short-term acute toxicity tests, while longer-term population dynamic related traits, critical to the success of biological control and Integrated Pest Management (IPM) programs, are often overlooked. This is increasingly important with respect to new biopesticides that frequently cause no short-term acute effects, but that can induce multiple physiological and behavioral sublethal effects, leading to a decrease in population growth and ecosystem services. In this study we assessed the lethal and sublethal effects of six biopesticides [abamectin, azadirachtin, Bacillus thuringiensis, borax plus citrus oil (Prev-Am®), emamectin benzoate, and spinosad], used in tomato crops to control the invasive pest Tuta absoluta (Lepidoptera: Gelechiidae), on adults and pupae of the parasitoid Bracon nigricans (Hymenoptera: Braconidae). Data on female survival and production of female offspring were used to calculate population growth indexes as a measure of population recovery after pesticide exposure. Spinosad caused 100% and 80% mortality in exposed adults (even 10 d after the treatment) and pupae, respectively. Although most of the biopesticides had low levels of acute toxicity, multiple sublethal effects were observed. The biocontrol activity of both females that survived 1-h and 10-d old residues, and females that emerged from topically treated pupae was significantly affected by the application of the neurotoxic insecticides emamectin benzoate and abamectin. Furthermore, very low B. nigricans demographic growth indices were estimated for these two insecticides, indicating potential local extinction of the wasp populations. Among the tested products, Bt proved to be the safest for B. nigricans adults and pupae. Our findings emphasize that acute toxicity assessment alone cannot fully predict the actual impact of pesticides on non-target parasitoids. Thus, sublethal effects related to the species specific life-history variables must be carefully considered in order to assess pesticide risks and to incorporate new pesticides, including biopesticides, into IPM programmes.

Among botanical extracts used as insecticides, essential oils (EOs) are promising alternatives to chemical insecticides. EOs are synthesized by plants, and they play a key role in plant signaling processes including also attractiveness toward pollinators and beneficial insects. Plant species producing essential oils (over 17,000 species) are called aromatic plants and are distributed worldwide. Our review aims to evaluate research studies published in the last 15 years concerning the use of EOs in stored product protection. More than 50% of the retrieved manuscripts have been published by authors from Eastern countries (Iran, China, India, and Pakistan), investigating different aspects related to insect pest management (exposure route, effect on the target pest, and mode of action). Coleoptera was the most studied insect order (85.41%) followed by Lepidoptera (11.49%), whereas few studies targeted new emerging pests (e.g., Psocoptera). Almost all the trials were carried out under laboratory conditions, while no experiments were conducted under real operating conditions. Future research studies concerning the use of EOs as insecticides should focus on the development of insecticide formulations which could be successfully applied to different production realities.