Spotted Wing Drosophila (SWD) Update – July 10, 2015

Spotted wing drosophila trap catches continue, predominantly in southern Ontario. In recent weeks we  trapped SWD in Essex, Kent, Elgin, Norfolk, Oxford, Middlesex, Brant, Haldimand, Niagara, Halton, as well as the eastern Ontario counties of  Quinte west  and Carlton.  Numbers are starting to increase in earliest areas. So far most of or trap catches are in wild hosts, often near strawberries, but we have also found them in raspberries, blueberries and cherries. Wild fruit is now ripe and will contribute to the buildup of SWD in the environment. SWD have been reared from strawberry and raspberry fruit collected June 23, indicating that in southern Ontario, flies were actively laying eggs in ripe fruit before that date.

Moderately warm and humid conditions are perfect for SWD.  All ripe and nearly ripe fruit is at risk for infection. Raspberries, cherries and early blueberries are at risk. Watch for unusually soft and leaky fruit. Berry growers who buy fruit from other growers should make sure these suppliers have SWD under control.

Raspberry growers should have all aspects of a management plan in place, including early and frequent harvest, and regular application of insecticides with a well calibrated sprayer.   Best options at this time  include Delegate, Entrust, Success, Malathion. Of these, all will control small caterpillars and loopers, but only malathion will control rose chafer.  Rotate products from different families as much as possible.

Blueberry growers should consider pre-harvest insecticides where berries are blue.  Options for blueberries include Delegate, Entrust, Success, Malathion, Imidan and Exirel. Imidan has a long phi (15 days) so is not that useful for SWD but both Imidan and Exirel also control Japanese beetle.

Cherry growers should choose an insecticide for cherry fruit fly that also controls SWD.

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.