Control of spotted wing drosophila (Drosophila suzukii) in sweet cherry and raspberry using bait sprays

Abstract

Spotted wing drosophila (Drosophila suzukii Matsumura) is a major pest of fruit crops with global signi cance. Effective control is reliant on uniformly spraying insecticides on all crop foliage. To encourage pest attraction and ingestion of insecticides, phagostimulant baits can be employed in 'attract and kill' strategies. In semi-eld trials we compared (1) full eld foliar sprays of two insecticides spinosad and cyantraniliprole, with (2) reduced [40%] and (3) low [4%] rates of the insecticides to control D. suzukii and reduce insecticide residues in fruit in sweet cherry and raspberry. The low rates of the insecticides were also combined with baits, (4) Combi-protec, a proprietary mixture of plant extracts, proteins and sugars, and (5) molasses; treatment (6) was an untreated control. In both crops, when combined with baits, low rates of insecticides gave comparable control of D. suzukii in fruits compared with the full rate sprays in most cases and D. suzukii was signi cantly lower in these treatments compared with the untreated controls. Crop spray coverage was eight and thirty times higher in the full rate applications compared with the bait and low rate sprays, in raspberry and cherry respectively. The reduction in applied insecticide was achieved by lower concentrations and a narrower band spray applied across the middle of the crop canopy. Insecticide residues in raspberries were < 11% of those sprayed with full rates, while no residues were detected in cherries. This study demonstrates that bait sprays can be effectively employed on crops with complex canopies for D. suzukii control. Key MessageBaits were used in an attract and kill strategy for spotted wing drosophila in raspberries and cherries Using bait sprays, insecticide rates could be reduced by 96% without losing D. suzukii control e cacy Spray deposition on the crop was ×8 to ×30 higher with full rate sprays compared with bait sprays Bait sprays took a tenth of the time to apply compared with full rate applications Using bait sprays instead of full rate applications reduced fruit insecticide residues by >89%

Sublethal effects of nine insecticides on Drosophila suzukii and its major pupal parasitoid Trichopria drosophilae

“…Chemical control involving broad spectrum insecticides still remains an important tool of the integrated management of D. suzukii and several approaches are being developed over time, e.g., modelling the best timing and order of insecticide classes, 43 and attract and kill strategies using reduced rates of pesticides 87 . In this context, compatibility between natural enemies and insecticides needs to be further investigated to develop comprehensive IPM programs against the D. suzukii .…”

Non-target effects of neurotoxic insecticides on Ganaspis cf. brasiliensis, a classical biological control agent of the spotted wing Drosophila

“…In this context, the abundant presence of D. suzukii close to harvest season has induced growers to rely on chemical control, which is mainly based on conventional and broad-spectrum insecticides sprayed according to calendar schedules (Tait et al 2021). Among these, pyrethroids, carbamates, organophosphates and diamides are the most common insecticides used by conventional farmers (Shawer et al 2018;Shaw et al 2019;Tait et al 2021), while spinosad, azadirachtin and pyrethrins are among the best options for the organic management of D. suzukii (Gress and Zalom 2019;Noble et al 2023). To date, most of the toxicological studies have focused on application methods, insecticide resistance and lethal toxicity towards D. suzukii (Van Timmeren et al 2018;Mermer et al 2021Mermer et al , 2023Noble et al 2023).…”

“…Among these, pyrethroids, carbamates, organophosphates and diamides are the most common insecticides used by conventional farmers (Shawer et al 2018;Shaw et al 2019;Tait et al 2021), while spinosad, azadirachtin and pyrethrins are among the best options for the organic management of D. suzukii (Gress and Zalom 2019;Noble et al 2023). To date, most of the toxicological studies have focused on application methods, insecticide resistance and lethal toxicity towards D. suzukii (Van Timmeren et al 2018;Mermer et al 2021Mermer et al , 2023Noble et al 2023). Toxicity and sublethal effects of insecticides have been evaluated for several non-target biocontrol arthropods species (Desneux et al 2007), including predators (Biondi et al 2012;Ricupero et al 2020) and parasitoids (Biondi et al 2013;Teder and Knapp 2019), but the agrochemical impact on D. suzukii parasitoids is still neglected.…”

Novel Lactone-Based Insecticides and Drosophila suzukii Management: Synthesis, Potential Action Mechanisms and Selectivity for Non-Target Parasitoids

“…The control of D. suzukii in the Neotropical region, as already described for Europe and the USA [ 5 , 6 ], is heavily dependent on the use of a few molecules (e.g., organophosphates, pyrethroids and the spinosyns) with very-well-characterized undesired effects on non-target organisms, including those that can provide naturally occurring biological control [ 5 , 6 , 7 ]. A possible alternative to foliar spraying is the use of toxic baits or low-volume, reduced-risk sprays in conjunction with feeding attractants [ 8 , 9 ]. However, although the use of these devices can substantially reduce the amount of insecticide applied, the efficiency can be strongly influenced by factors such as the high density of insects, unharvested fruits, and other alternative host fruits in the field, in addition to the physiological aspects (e.g., reproductive maturity, age, mating status) of insects [ 10 , 11 ].…”