Massachusetts IPM Berry Blast
July 1, 2016
Spotted Wing Drosophila UPDATE
The Massachusetts SWD monitoring network has still not confirmed any SWD captures. We are monitoring 9 locations around the state. Surrounding states report sporadic captures of mostly individual male or female flies. However, increasing amounts of both wild and cultivated host fruit is likely to promote SWD development and we expect to see SWD in our traps in the coming week. This year there is also a possibility that SWD are infesting strawberries in some areas and so it is important to harvest thoroughly and renovate promptly after strawberry harvest is complete. Unharvested strawberries left behind in unrenovated fields provide a prime resource for SWD populations to build up and become a more significant problem in later season berry crops.
What does this mean?
- Renovate strawberry fields
as soon as possible after harvest is complete.
- In blueberries
, once you have confirmed SWD presence at your farm with traps or fruit infestation or field history predicts early infestation, once fruit coloring begins you should follow the 3 point program of
1) frequent and thorough harvest
2) prompt refrigeration of harvested fruit
3) spray program (organic or conventional) using recommended materials at intervals of no more than 7 day, rotating IRAC classes to avoid developing a pesticide resistant SWD population.
In addition, keep in mind that if a significant rainfall occurs
after a spray application, the material may need to be reapplied. See article from Michigan State University on Rainfast Characteristics of Spray Materials
Once harvest begins, it is recommended that you conduct a salt flotation test
on your fruit on a regular basis to determine if SWD egg laying has occurred. An excellent description of how this test is performed written up by Ohio State University Extension Specialist Celeste Welty can be found at this location: http://entomology.osu.edu/welty/pdf/ProtocolSWD_larvae24April.pdf
It may also be helpful to install some support trellising in raspberries and blueberries to hold heavily fruit laden canes or branches up and off the ground. This creates air space between the humid shady ground (which SWD like) and the susceptible fruit and can lessen infestation levels.
Finally, exclusion netting has been shown to provide some protection from SWD infestation and can be a viable option for certain situations, especially for organic growers whose spray material options are very limited. See this article
from UVM that describes their findings using exclusion netting. Another excellent source of information on the use of exclusion netting can be found in a Northeast SARE report from New York Berry Grower Dale Ila Riggs at: http://mysare.sare.org/sare_project/fne14-813/?page=final&view=print
Archived IPM Berry Blasts are available at the UMass Extension Fruitadvisor website.
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