Drosophila suzukii control: Intervention in organic stone fruit orchards

Summary

The combination of preventive measures and intervention measures can reduce due to D. suzukii puncture and/or development of larvae inside the fruits, and therefore minimise economical losses.
Practical recommendation
• Netting (+++): Use nets whit meshes that do not deform and a max. mesh size of 1.0x1.0 mm. Close the nets immediately after flowering. Avoid contact of the net with fruits. This measure is not possible for high-stem cherry orchards.
• Mass trapping (++): Suitable for apricot and plums but does not work from the beginning of cherry rip-ening onwards, as cherries are more attractive than the bait trap. Use commercial or self-built traps out of plastic bottles with 5 mm holes on the top (best in red or black). Self-made bait mixture: 1/3 water, 1/3 apple cider vinegar, 1/3 red wine, 0.05% acetone (optional), and two drops of odourless liquid soap.
• Spraying kaolin or slaked lime as a deterrent (+): Kaolin (2 %) or slaked lime (0.18 %) application with 500-1000 l/ha water during warm weather conditions (>20 °C) and low relative humidity (~30 %). Spray weekly from colour change of fruits (from yellow to red) on. It causes spray stains and therefore is un-suitable for crops for fresh consumption.
• Spraying Spinosad (+): Spinosad (0.02 %) has a partial effect, not sufficient as a sole measure. This treatment causes measurable residues: Strictly adhere to waiting periods and application rates. It is toxic to beneficial insects and bees: do not apply on crops still in bloom and on damaged fruit with juice discharge. Check if Spinosad is approved or needs a special permit in your country.