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Ontario spotted wing drosophila late August update


August 28, 2013
By Pam Fisher OMAF

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August 27, 2013, Simcoe, Ont – Growers should assume spotted wing drosophila is now present throughout all of Ontario.

As the season progresses, SWD populations will continue to build up. Fall-bearing raspberries, blueberries, blackberries, elderberries and day neutral strawberries are among the most susceptible crops at this time. The first sign of trouble is unusually soft and juicy fruit, with an unusually poor shelf-life.

  • Raspberries: A post-harvest spray is recommended to reduce risk to nearby susceptible crops such as fall bearing raspberries or blueberries.
  • Fall bearing raspberries: Begin to spray for SWD as the main crop begins to ripen. Use saltwater tests to determine how well your spray program is working. Harvest thoroughly and often, every two to three days if you can.
  • Blueberries: Continue with weekly insecticides if you plan to be harvesting marketable fruit seven to 10 days from now. Try to pick parts of the field clean, and follow up with an insecticide in that block.
  • Day neutral strawberries: Watch for damage that looks like bruising on one side of the fruit. Include an insecticide for SWD every seven to 14 days.
  • Elderberries: Begin a weekly insecticide program as the fruit is colouring.
  • Blackberries: Apply weekly insecticides throughout harvest.
  • Wild hosts: Do not spray insecticides on wild hosts.

A detailed weekly update is available at www.ontario.caspottedwing.

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Click here for Insecticides for SWD. Your choices include Malathion, Entrust, Delegate, Ripcord. Delegate is a good choice at this time. Malathion is effective but lacks residual activity, especially when it rains. Ripcord is hard on mite predators that help keep spider mites in check, it is less effective in hot weather, and is a better choice for later in the season.

SWD is a manageable pest, but the first step for control is awareness. Talk to your neighbours at market, and down the road, about SWD. SWD is causing significant damage where growers are not aware of the problem. Encourage them to review the information at www.Ontario.ca/spottedwing Fruit quality in the berry industry is everyone’s concern.

What do you need to know about SWD? How did you manage it in 2013? Help me focus on your top priorities by sending me an email (or just call) with your questions about SWD.