Canopy strip applications of Hanseniaspora uvarum combined with spinosad reduce insecticide use without compromising Drosophila suzukii control in cherry

Drosophila suzukii, a significant sweet cherry pest, has traditionally been controlled using broad-spectrum insecticides. Various yeasts are known to attract and stimulate flies to feed on yeast-covered surfaces. We investigated an attract-and-kill formulation based on the yeast Hanseniaspora uvarum and the insecticide spinosad, applied to an 80–100 cm wide canopy strip at 1-m height in six field trials across Italy and Germany to manage D. suzukii infestation in cherry. The attract-and-kill formulation, applied at a dose ranging from 21.6 to 34.9 g per hectare of spinosad, according to the training system, decreased the percentage of D. suzukii infested cherries by 41.74–84.26% and the average number of deposited eggs by 79.51–95.56%. The efficacy was comparable to the conventional application of spinosad alone, which was applied at a dose ranging from 84 to 216 g per hectare. The conventional application decreased the percentage of infested cherries by 53.00–92.00% and reduced the number of deposited eggs by 77.10–92.96%. The attract-and-kill technique led to a reduction of up to 90% of insecticide use by targeting the application on limited section of the cherry tree. The targeted approach not only minimized insecticide quantities per hectare, but also resulted in lower residue levels on treated fruits.