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Ontario SWD update


September 7, 2011
By OMAFRA

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spottedwingdrosophilaflyNEWS HIGHLIGHT

Ontario SWD update

Spotted Wing Drosophila (SWD) has now
been detected in several counties in Ontario including Essex, Kent, Niagara,
Norfolk and Oxford. All of the finds have occurred in commercial stone fruit
and berry crops. The counts listed below represent traps collected the week of
Aug. 15 to 23. There have been no reports of infested fruit to
date.

September 6, 2011 – Spotted Wing Drosophila (SWD) has now
been detected in several counties in Ontario including Essex, Kent, Niagara,
Norfolk and Oxford. All of the finds have occurred in commercial stone fruit
and berry crops. The counts listed below represent traps collected the week of
August 15th to 23rd. There have been no reports of infested fruit to
date.

  • Essex – 2 SWD males, 2 SWD females             
  • Kent – 1 SWD male             
  • Niagara – 1 SWD male (August 8th-15th), 1 SWD female (August
    15th-22nd)             
  • Norfolk – 1 SWD female             
  • Oxford – 1 SWD male
spottedwingdrosophilafly 
  

Berry crops are very susceptible to this new pest and we
expect SWD activity will increase in these crops for the next few weeks. Now
that blueberry harvest is essentially finished, fall-bearing raspberries and
day-neutral strawberries are probably most at risk at this time.

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There are no thresholds established yet for this pest. We
can only recommend that you protect ripening berry crops in areas where the
pest present. If you have fall-fruiting raspberries or day neutral
strawberries, then you should also consider a post harvest sprays on
blueberries and summer raspberries, to prevent SWD from building up on in
unharvested fruit and then moving into your later crops.

Registrations are in place for SWD control in 2011, in berry
crops, tender fruit and grapes. For more information and links to the labels:
http://www.omafra.gov.on.ca/english/crops/facts/swd-registrations.htm. Here are
a few comments on these products.

Delegate WG: Active ingredient is spinetoram. Also controls
caterpillars, and thrips. 

Pre-harvest intervals: Strawberries: 1 day; Raspberries: 1 day; Blueberries: 3 days

Entrust 80W: 
Active ingredient is spinosad, belongs in the same family as Delegate.
Entrust is acceptable to most organic certifiers.

Pre-harvest intervals: Strawberries: 1 day; Raspberries: 1 day; Blueberries: 3 days

Malathion 85E: This is a broad spectrum organophosphate
insecticide. Expect some leaf burn when Malathion is used on raspberries,
especially in hot weather.

Preharvest intervals: Strawberries: 3 days; Raspberries: 1 day; Blueberries: 2 days

Ripcord 400 EC: 
Using Ripcord in berry crops, especially late season. can be problematic
because pyrethroid insecticides are 
toxic to beneficial insects and can lead to more problems with mites. It
is interesting that the pre-harvest interval is shorter for SWD than it is for
other pests on strawberries. 

Pre-harvest intervals: Strawberries, Raspberries, Blueberries: 2 days

Growers should be on the lookout for SWD infested fruit.
Watch for fruit that is soft, or showing premature decay. You can try a
salt-water test to check for SWD larvae in fruit. Place one to two pounds of
berries in dark-coloured pan and cover completely with salt water (one cup salt
in one gallon of water). If SWD is present, small white larvae will float to
the top in about five to 10 minutes.


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