SWD Management in Raspberries & Blackberries


New York State’s rainy spring and hot, humid summer has caused spotted wing drosophila populations to swell. Raspberries are more susceptible to the pest than any other berry crop, so arming yourself with information and control methods is a must.

The most important defense for raspberries against SWD is a good insecticide program. In order to determine the best program for your farm, consider:

  • Population growth—growth models will give you an idea of SWD population size, and allow you to treat with the most effective insecticides before numbers get out of control.

  • Insecticide rotation—using treatments from different IRAC groups reduces resistance in SWD.

  • The most effective insecticides—according to researchers at Cornell University, these include Delegate WG (1 day), Bifenture 10DF (3 days), Brigade WSB 2(ee) (3 days), Brigade EC 2(ee) (3 days), Danitol 2.4EC (3 days), and Mustang Maxx (1 day). They recommend, “Choose first the one with the longest pre-harvest interval (given in parentheses) that you can accommodate; some may be out of the question at this point. Rotate to other insecticides with shorter pre-harvest intervals for closer to harvest.”

  • Subsequent applications—try a lower-efficacy insecticide, including Entrust Naturalyte 2(ee) (1 day), Entrust SC 2(ee) (1 day), Assail 30SG 2(ee) (1 day), Malathion 5EC 2(ee) (1 day), Malathion 8 Aquamul 2(ee) (1 day), Malathion 57 2(ee) (1 day), or Molt-X (0 days). Don’t stretch intervals between sprays by more than 7 days!

  • Know your organic-approved sprays—like Entrust 2(ee) (1 day) (Naturalyte and SC formulations). Rotate with either Pyganic (0 days), AzaSol (0 days), Grandevo (0 days), or Venerate (0 days).

  • Ensure that you cover crops completely—instead of alternate-row spraying, spray every row. And know your spraying intervals for each type of insecticide.

  • Re-set raspberry and blackberry fields—following high numbers of SWD in traps or salt flotation tests, re-set the field by clean-picking all ripe fruit and culling. Freeze or solarize infected fruit. You should do this regularly as part of your sanitation program. Then use a high-efficacy insecticide on your fields with an appropriate days-to-harvest interval.

  • Mow, weed, and prune—this will minimize the damp, shaded environment SWD prefer, eliminate alternate hosts, and improve spray penetration.

  • Follow good cold-chain practices—store harvested fruit, as soon as possible after harvest, in a cool at 32 to 24 degrees F to slow and kill SWD larvae and eggs.

For more details, monitoring tips, and additional resources, visit the Cornell IPM blog.