Evaluation of non‐target effects of OMRI‐listed insecticides for management of Drosophila suzukii Matsumura in berry crops

Abstract

The spotted wing drosophila, Drosophila suzukii Matsumura, is an invasive pest of many fruit crops throughout North America, South America and Europe. The presence of this destructive pest has led to an increase in the number of insecticide applications. While conventional growers have an arsenal of different insecticides at their disposal, organic growers have a limited selection of effective options and rely heavily on applications of Entrust ® , the organic formulation of spinosad. An important part of research is to develop more tools for organic growers and evaluate the effects of insecticides intended to target D. suzukii on natural enemies in the system.The effects of six organic pesticides alone and in combination with three adjuvants and two phagostimulants were tested in laboratory bioassays on three common natural enemies in berry production systems including two predators, Chrysoperla rufilabris and Orius insidiosus, and a parasitoid wasp, Aphidius colemani. Under the IOBC toxicity rating scale, spinosad was rated consistently from slightly harmful to harmful across natural enemy species and residue age (the effects of pesticides over time). Sabadilla alkaloids caused mortality to O. insidiosus equal to that of spinosad.All tested pesticides were at least slightly harmful to A. colemani, and the adjuvant polyether-polymethylsiloxane-copolymer polyether caused mortality that was not significantly different from spinosad. In general, neither the addition of adjuvants nor phagostimulants increased the mortality of the insecticides tested. The exception was polyether-polymethylsiloxane-copolymer polyether, but it is unclear whether it increased the toxicity of the pesticides or was simply toxic itself since it caused high mortality to A. colemani when applied alone. Sublethal effects were measured for two predatory species by measuring eggs laid and % egg hatch. Minimal sublethal effects were observed in C. rufilabris. In contrast, all tested insecticides caused reduced egg hatch in O. insidiosus compared with the control. K E Y W O R D S adjuvant, Aphidius colemani, Chrysoperla rufilabris, Orius insidiosus, phagostimulant, spotted wing drosophila | 13 SARKAR et Al.

Plastic mulches reduce adult and larval populations of Drosophila suzukii in fall-bearing raspberry

“…Recently, D. suzukii has been reported to show reduced sensitivity to some active ingredients, including spinosad, the main insecticide used to control D. suzukii in organic systems (Van Timmeren et al 2018;Gress and Zalom 2019). Other concerns about frequent insecticide use include negative health impacts on farm workers from pesticide exposure (McCauley et al 2006;Flocks 2012;Schwartz et al 2015), declining populations of beneficial insects (Roubos et al 2014), and potential secondary pest outbreaks (Sarkar et al 2020). Cultural practices can help manage D. suzukii, including cultivar selection, pruning or trellising, exclusion netting, harvesting fruit promptly, field sanitation, proper disposal of infested fruit, and post-harvest cold storage (Leach et al 2016(Leach et al , 2018Hooper and Grieshop 2020a, b;Schöneberg et al 2020Schöneberg et al , 2021.…”

Olfactory behavioral responses of two Drosophila species and their pupal parasitoid to volatiles from bananas

“…Spinosad is harmful to the predators Chrysoperla rufilabris (Neuroptera: Chrysopidae) and Orius insidiosus (Hemiptera: Anthocoridae), and the parasitoid wasp Aphidius colemani (Hymenoptera: Aphidiidae). The egg hatch rate of O. insidiosus is significantly reduced by insecticide treatment 21 . However, as indicated by studies of D. melanogaster , Drosophila spp.…”

Assessing potential hybridization between a hypothetical gene drive‐modified Drosophila suzukii and nontarget Drosophila species

“…Drosophila suzukii has a serrated ovipositor and lays its eggs into undamaged ripening fruits and berries, causing major damage and revenue losses. Controlling this pest by conventional means (e.g., insecticides, antagonists, and behavioral manipulation) is very challenging, labor intensive, costly, and, in the case of insecticides, comes with environmental costs (Sarkar et al., 2020; Tait et al., 2021). Therefore, alternative control measures including genetic control approaches such as geGDs have been suggested (Schetelig et al., 2018; Romeis et al., 2020).…”