Spotted Wing Drosophila (SWD) Update – July 17, 2015

Spotted wing drosophila trap captures have escalated this week!  (Figure 1.) Do not take chances with SWD control right now.

• SWD was present at 50% of the monitored sites last week and is approaching 80% of sites this week.   (Traps are not 100% efficient for individual sites, so we use regional trednds to predict activity)
• The number of flies per positive trap has increased dramatically, especially in southern Ontario, were 2-3 generations are completed. (Figure 2)
• The biggest increases are in wild hosts, strawberries, raspberries and unsprayed stone fruit such as apricots. This means that SWD are multiplying in these crops.
• We have trapped SWD in eastern Ontario as well. Numbers are lower, but berry crops in eastern Ontario are also at risk.

Summer red raspberries: Apply weekly insecticides. Harvest as thoroughly as possible every 2 days. This is difficult given the big crop but it is at risk in all areas!

Fall-bearing raspberries: Strip ripening fruit off the lower parts of the plant until there is enough fruit to harvest every 2 days. Begin a regular insecticide program as primocane fruits begin to ripen.  Do not let SWD build up on the small crop that develops early at the base of the plant.

Blackberries: Where fruit is ripening, begin an aggressive insecticide program and harvest as thoroughly and as often as possible.

Blueberries: Harvest is in progress and fruit is susceptible. Apply a preharvest insecticide to blocks of late varieties green fruit, choosing an insecticide which will also control Japanese beetle. Apply insecticides weekly once fruit begins to ripen. Do not skip these early insecticides, which are critical to keeping populations under control.

Day neutral strawberries: Ripe fruit is susceptible now. Harvest thoroughly every 2 days.  Begin an insecticide program when fruit becomes abundant.

June bearing strawberries: Unharvested fruit is now a source of SWD. Mow and renovate as soon as possible. Apply a post harvest insecticide to blocks adjacent to raspberries or blueberries..

Cherry and tender fruit growers should choose insecticides for cherry fruit fly  or oriental fruit moth that also control SWD.

All berries and stone fruit crops: Do salt water assessments and close observation to check for SWD damage. Juice leaking from fruit indicates a serious problem.  Keep fruit in a cooler, as soon as possible after harvest.

Insecticide recommendations for all fruit crops can be found at: http://www.omafra.gov.on.ca/english/crops/facts/swd-registrations.htm. 

In addition to the list at this link, Entrust and Success are now fully registered for SWD on berry crops We will update our on-line information to reflect this as soon as possible.