Spotted Wing Drosophila (SWD) update July 22, 2016

SWD  adults trapped in the Ontario regional monitoring program have increased dramatically this week. We are now catching over 10 flies per trap at many sites which generally means that damage to crops is occurring. More SWD are being trapped in crops, not just the wild hosts around the farm.  Low levels of damage have been detected in raspberries and day neutral strawberries.

  • More sites with SWD
  • More counties where SWD has been trapped (+Wellington, Peterborough, Northumberland).
  • All ripening fruit at risk
  • Huge increase in numbers of SWD, especially near June bearing strawberries, and wild raspberries.
  • Damage detected in commercial fruit

swdchart0722

SWD trap captures from 30 sites across Ontario

All growers should assume that SWD is present now.  Fruit which is ripening is at risk for SWD damage.  SWD should be managed by picking fruit early, thoroughly and often. Keep fruit cold after harvest. Weekly sprays will help keep SWD under control and are now required on all ripening fruit. A list of registered insecticides for SWD can be found here:  Ontario.ca\spotted wing – products registered for SWD .

Salt water assessments of harvested fruit should be done routinely as an early warning of SWD problems. http://www.omafra.gov.on.ca/english/crops/facts/swd-saltwater.htm

In summer fruiting raspberries growers have typically managed SWD by harvesting thoroughly every day or two. However, this year, the crop is earlier, abundant and SWD numbers are higher than usual. An insecticide should be included in your SWD management program if you expect to continue harvesting into next week.  A postharvest spray on raspberries is a good idea if fruit is left behind as you move from one variety (i.e. Prelude) to the next.

In fall bearing raspberries, SWD can build up on the early fruit at the base of the cane. If you are not harvesting this fruit, consider removing it. If this is not possible, direct a nozzle to the base of the canes and start an insecticide program now on fall bearing varieties where fruit is ripening.

Blueberry harvest is in progress. Apply a pre-harvest insecticide for SWD to later varieties now as you harvest Duke and early varieties. Exirel will control both SWD and Japanese beetle.  This is a critical time to begin a control program for SWD.

Strawberries should be mowed and renovated as soon as possible after harvest. Mowing strawberries will help fruit to dry up and make it less attractive to SWD.  Growers who are renovating strawberries do not need to spray for SWD unless they have raspberries or blueberries or other susceptible fruit close by.  Cygon or Lagon, when sprayed to control aphids in strawberries, is also toxic to SWD flies, and would be a good choice at renovation.

Day neutral strawberries– especially overwintering fields, are also susceptible to SWD now and some damage has been observed. Tarnished plant bug is also building up in day neutrals. Malathion for SWD will also control tarnished plant bug, and is a good choice now.  Avoid use of Mako at this time, because it can lead to more problems with spider mites.   Mako will work well in cooler weather.

Cherries: As cherries colour they will become more attractive to SWD.   Consider using an insecticide that controls both cherry fruit fly and SWD in pre-harvest sprays. Delegate, Entrust, Success, Exirel, and Silencer would likely control both pests, if the timing and coverage are good.

swdtable0722Ontario.ca\spottedwing

 

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This entry was posted in Berries, Blueberries, Cherries, Currants, Elderberries, Cranberries and more, Insects and Diseases, Raspberries, Strawberries, Tender Fruit, Uncategorized and tagged , , , , , , , . Bookmark the permalink.

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