Bait sprays for suzuki fruit fly control in fruit crops

Bait sprays are an effective, targeted method for managing Suzuki fruit flies (Drosophila suzukii) in Dutch soft and stone fruit crops. This approach combines low-dose insecticides—such as Tracer (spinosad) and Exirel (cytaniliprole)—with the adjuvant Combi-protect to attract and kill adult flies. Field trials show 87–90% reductions in fly populations. The technique minimises environmental impact, reduces spray drift, and preserves natural predators. Optimal results require coarse droplets applied directly to fruit or leaf undersides, especially in warm, dry, or dense foliage conditions. Effectiveness declines within hours due to rain and degradation, though residues last longer under protective covers. Dosage is low (5–10% of standard rate), applied at 1–2 L/ha Combi-protect with 20–40 L water. Repeated use increases resistance risk; Tracer prevents egg-laying, while Exirel does not. Legal application limits, drift reduction, and pollinator protection are essential. Research by Knick et al. (2019), Noble et al. (2021), and Engel (2017) supports efficacy. Contact Herman Helsen, WUR, for further details.