Spotted Wing Drosophila – Facts for Fancy Fruit

Spotted Wing Drosophila

Spotted wing drosophila continue to plague raspberry, blackberry, blueberry, and grape growers. I have had some reports of poor control. There are a number of reasons that control of any insect may be poor. If you are not getting the level of control you expect, here are a few things to consider.

  1. Is your sprayer calibrated correctly? Are you putting on the right amount of insecticide?
  2. Is your coverage adequate? Yellow water sensitive cards can be an economical way to determine is the spray is getting where you need it to be.
  3. What is the pH of your water? If it is too high, you may need to adjust it to get down close to 7 or below.
  4. How hard is your water? If the hardness level is 250 or higher, you may need to soften the water before mixing the insecticide.
  5. What is the interval between sprays? For this insect, weekly sprays appears to be the bare minimum. Some growers are spraying twice weekly and getting good results, but an interval of 4-5 days should be sufficient in most cases. I know that’s pretty close to twice per week but over the course of the season you might save a spray or two.

Growers should expect to continue spraying to control SWD until the end of the season. Our data so far show that they remain active as long as you are picking.

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