Overview of the testing and assessment of effects of microbial pesticides on bees: strengths, challenges and perspectives

Abstract

Currently, there is a growing interest in developing biopesticides and increasing their share in the plant protection market as sustainable tools in integrated pest management (IPM). Therefore, it is important that regulatory requirements are consistent and thorough in consideration of biopesticides’ unique properties. While microbial pesticides generally have a lower risk profile, they present special challenges in non-target organism testing and risk assessment since, in contrast to chemical pesticides, their modes of action include infectivity and pathogenicity rather than toxicity alone. For this reason, non-target organism testing guidelines designed for conventional chemical pesticides are not necessarily directly applicable to microbial pesticides. Many stakeholders have recognised the need for improvements in the guidance available for testing microbial pesticides with honey bees, particularly given the increasing interest in development and registration of microbial pesticides and concerns over risks to pollinators. This paper provides an overview of the challenges with testing and assessment of the effects of microbial pesticides on honey bees (Apis mellifera), which have served as a surrogate for both Apis and non-Apis bees, and provides a foundation toward developing improved testing methods.

Biopesticides and insect pollinators: Detrimental effects, outdated guidelines, and future directions

“…Unfortunately, it appears clear that most classes of biopesticides can have species-specific deleterious effects, making generalitation across taxa a dangerous game. The recent review by Borges et al (2021) has already pointed out that in the case of different microbial biopesticides, infectiveness and pathogenity should be assessed in different life stages. We add that the same should be done in different taxa other than bees, since biopesticides can have multiple adverse effects on them (Figs.…”

“…It is important to underline that the present review does not intend to condemn the use of biopesticides, as their application is undoubtedly higly preferable and more ecofriendly with respect to synthetics chemicals. Our aim, instead, is to increase awareness about the inadequacy of unique representative models in risk-assessment protocols and the urgent need for the development of comparative protocols testing multiple pollinator species, from solitary to social, to assess all the potential adverse side-effects that biopesticides could have on insect pollinators (Borges et al, 2021). Only through the careful evaluation of the lethal action and sublethal effects of biopesticides, and their potential synergistic interaction on a larger array of functional groups of pollinating insects, we will be able to successfully preserve the fragile ecological balance and the relationships among plants and pollinators (Klein et al, 2007).…”

“…A second, often neglected issue when assessing biopesticides' safety resides in the fact that these substances, as for synthetic chemicals, have been mostly tested on very few commercially relevant non-target model species. Indeed, A. mellifera and B. terrestris alone serve as models for (bio)pesticide toxicity testing (Franklin and Raine, 2019;Klinger et al, 2019), and regulation agencies do not require toxicity testing on other pollinators, despite the considerable variability across species (Borges et al, 2021).…”

“…Despite the growing body of research on the effects of synthetic pesticides on non-target insects, the attention paid to such relevant subjects with respect to biopesticides is still limited and fragmentary. A very recent review by Borges et al (2021) has highligthed the challenges to test and assess the effects of microbial pesticides on honey bees and to expand the obtained results and risk assessment protocols to non-Apis bees, but without focusing on the array of potential adverse effects on other taxa of pollinators. Thus, in the present review, we provide an overview of the effects of the major classes of biopesticides described so far on pollinating insects (Fig.…”

Towards Sustainable Green Adjuvants for Microbial Pesticides: Recent Progress, Upcoming Challenges, and Future Perspectives

“…Green pesticide is harmless to human health, friendly to the environment, ultra-low dosage, high selectivity, and through the green process to produce pesticides [ 23 ]. At present, most of the adjuvants used in microbial pesticides still refer to those of chemical pesticides [ 24 ]. A green adjuvant is a kind of non-toxic, harmless, and good biodegradable adjuvant added in the process of pesticide production [ 25 ].…”