Are Botanical Biopesticides Safe for Bees (Hymenoptera, Apoidea)?

Abstract

The recent global decline in insect populations is of particular concern for pollinators. Wild and managed bees (Hymenoptera, Apoidea) are of primary environmental and economic importance because of their role in pollinating cultivated and wild plants, and synthetic pesticides are among the major factors contributing to their decline. Botanical biopesticides may be a viable alternative to synthetic pesticides in plant defence due to their high selectivity and short environmental persistence. In recent years, scientific progress has been made to improve the development and effectiveness of these products. However, knowledge regarding their adverse effects on the environment and non-target species is still scarce, especially when compared to that of synthetic products. Here, we summarize the studies concerning the toxicity of botanical biopesticides on the different groups of social and solitary bees. We highlight the lethal and sublethal effects of these products on bees, the lack of a uniform protocol to assess the risks of biopesticides on pollinators, and the scarcity of studies on specific groups of bees, such as the large and diverse group of solitary bees. Results show that botanical biopesticides cause lethal effects and a large number of sublethal effects on bees. However, the toxicity is limited when comparing the effects of these compounds with those of synthetic compounds.

Evaluation of the Essential Oils Used in the Production of Biopesticides: Assessing Their Toxicity toward Both Arthropod Target Species and Beneficial Pollinators

“…Only in recent years has the number of studies aimed at establishing the degree to which biopesticides influence taxonomically close species to the target species increased. A volatile oil may be completely harmless to humans or other vertebrate species but may significantly interfere with the metabolism of the species of insects that belong to the same family due to the structural and functional similarities between them [4,144,145].…”

“…Because of their elevated volatility, there has been a growing trend in recent years to suggest encapsulating the essential oils used in commercial insecticides [11,145]. This method has both advantages and disadvantages; it favors the persistence of the essential oils in the environment and the extension of their action time.…”

“…Performing treatments in the laboratory or in the open field: Most experimental studies are conducted under laboratory conditions [58,93,145,150], with fewer directly in the field [55,65] or comparatively (in the laboratory and field) [108]. The latter emphasizes the idea that laboratory studies cannot always be extrapolated to field conditions; in order to certify a certain effect of an oil (both against harmful species and against the non-target ones, especially the useful ones), additional investigations are necessary.…”

High-energy emulsification of Allium sativum essential oil boosts insecticidal activity against Planococcus citri with no risk to honeybees

“…Concerning botanicals, EOs were extensively investigated for the potential use in beekeeping for controlling Varroa spp. mites or other parasites on A. mellifera, and the majority of these compounds showed low toxic effects for honeybees (Ntalli et al 2022;Catania et al 2023). The present study tested the garlic EO-based nano-emulsions (i.e., SN, SH, and HPM) for selectivity toward A. mellifera.…”

Toxicity of the Hexane Fraction of Fruits and Seeds of Ricinus communis to Caterpillars of the Spodoptera Complex

“…The perspectives are promising in the context of integrated pest management (IPM), extrapolating the frontiers of use by small producers, since botanical insecticides associated with other control strategies can contribute to the reduction of doses and applications of synthetic insecticides [14]. Furthermore, the botanical insecticides studied are usually environmentally safer compared to synthetic insecticides, as reported for bees [15,16] and parasitoids [17].…”