Can low-risk insecticides negatively affect the generalist predator Orius insidiosus (Hemiptera: Anthocoridae)?

Many insecticides can disrupt key natural enemies, such as Orius insidiosus Say, resulting in arthropod pest outbreaks and/or resurgences of minor and major pests. Some of these insecticides used to control pest arthropods can be lethal or have sublethal effects on natural enemies through direct contact, residual exposure, or ingestion, thereby reducing the natural enemy's ability to provide biocontrol and ecosystem services and making them less effective in inundated releases. Thus, further studies are needed to determine the negative effects of reduced-risk insecticides with low mammalian toxicity and less environmental impact on important natural enemies. Our objective was to evaluate the lethal and sublethal effects of two low-risk insecticides in the reduced-risk category, horticultural oil, and insecticidal soap, on eggs, nymphs, and adults of O. insidiosus. These are common insecticides used in arthropod pest management in conventional and/or organic crop production due to their effectiveness and low mammalian toxicity. We assessed the survival and developmental time of immatures (eggs and nymphs) and fecundity, fertility, and longevity of adults (males and females), and viability of eggs when exposed to the prepared treatments using the high label rate recommended for vegetable crops (high rate) and 10% of the high label rate (low rate) of horticultural oil and insecticidal soap and the distilled water control in the laboratory through contact, ingestion, and residual exposures. Our results show some negative lethal and sublethal effects of horticultural oil and insecticidal soap on the life history parameters of O. insidiosus.