2017 Ontario Trap Catches: Spotted Wing Drosophila
Table of Contents
Current update for Ontario
Dave Jones, from MSU extension, wrote an article on SWD management and approaching it similar to disease management. The article includes how to use trap counts- not as a tool to determine when to spray, but to learn what the pest is doing and where it is in the field. Trap counts let us know when the populations are building and when they start flying in the summer but do not show the risk of fruit contamination. Instead, once SWD is found in your fields you need to start regular management, including but not limited to insecticides. To read more about their SWD recommendations click here.
If you have ripe fruit it is at risk of SWD infestation. SWD numbers continue to climb and populations will grow for the rest of the summer. Optimal temperatures for SWD are between 20-25°C, which is contributing to the high population this year.
SWD management is a combination of weekly insecticides, regular, thorough picking (every 2 days or less) and immediate post-harvest cooling to 5°C or cooler. Re-apply an insecticide after a rain to maintain coverage- reapplication is needed after 1/2 inch of rain.
Pyrethroid insecticides (Mako) will not work well in hot weather and will cause an increase in mites. Save these insecticides for later when weather is cooler and mite pressure is lower.
Renovate June-bearing strawberries as soon as possible to dry up the remaining fruit, making it less attractive to SWD.
Here are some recommendations for SWD management in all berry crops:
- Calibrate your sprayer. There is no room for error, especially when spraying close to harvest.
- Strip bloom and fruit buds from new plantings which won't be harvested.
- Keep weeds and vegetation mowed or otherwise controlled in and around the field.
- Cool fruit as soon as possible after harvest and keep it cool.
- Develop a system for managing waste fruit. Whenever possible, fruit should be removed from the field. At the very least, unmarketable fruit should be picked off the plant and dropped in alleys and crushed. Fruit which is discarded from coolers or pack sheds should be sealed up in plastic bins or bags, or buried daily at least two feet deep.
- Get set up to monitor for SWD damage by floating fruit in salt water to look for larvae. For information on the "salt test" see ontario.ca/spottedwing under monitoring. Pay attention to nighttime temperatures. Warm nights lead to more SWD activity and more rapid SWD development. Adjust harvest and spray schedules accordingly.
- Make sure temperatures are below 25°C before you spray to avoid spray burn.
What do June-bearing strawberries, summer raspberries and haskaps
have in common? They could be targeted by SWD this year, in addition
to the usual suspects. The late strawberry and haskap varieties
combined with the early, high SWD pressure means that these crops
may need to be managed for SWD. If your summer raspberries haven't
historically had an SWD problem, that might not be the case this
We have found sustained SWD catches in most of the traps we have set up across the province. If you are beginning to harvest late strawberry varieties such as Malwina consider applying an insecticide, or keeping the field clean with regular, thorough picking and immediate post-harvest cooling to less that 5C or cooler.
We have sustained SWD catches in most of the traps we have set up across the province. In Michigan they have the 'summer surge' of SWD, 3-4 weeks earlier than usual. We have found over 100 flies in one of our traps and I expect the catches to jump next week. If you are not monitoring on your farm make sure you are protecting any ripe fruit- all ripening fruit is at risk. SWD management is a combination of weekly insecticides, regular, thorough picking and immediate post-harvest cooling to less that 5C or cooler. Re-apply an insecticide after a rain to maintain coverage. Renovate June-bearing strawberries as soon as possible to dry up the remaining fruit and making it less attractive to SWD.
Salt water assessments should be done regularly as an early sign of SWD problems.
This year we are doing a very small scale regional monitoring program. Use these results in addition to your own monitoring program to determine when SWD is present. Conduct a salt water test or a plastic baggie test to confirm presence.
The monitoring program is coordinated by the OBGA. Michigan and New York are catching SWD and have seen a jump in numbers this week, and one of our sites in Niagara has seen a jump this week as well. We expect the numbers to increase in other areas of the province this coming week so keep an eye on your fruit and have a management plan ready.
SWD has been identified in traps in Ontario, in Essex, Kent, Wellington, Brant, Niagara, Norfolk, and Haldimand , Stormont, Dundas & Glengary, and Ottawa/Carleton.
|Week Traps Collected||# sites with SWD/ # sites checked||# SWD trapped||Ave # SWD/trap||Counties where SWD was found||Crops where SWD was trapped|
|Essex, Kent, Wellington, Brant, Niagara, Norfolk, Haldimand||Blueberry, Raspberry,
|Essex, Kent, Wellington, Brant, Niagara, Norfolk, Haldimand,
Stormont, Dundas & Glengary,
|Raspberry, Blueberry, Haskap, Wild Host, DN strawberries|
- Check the SWD product registrations on our website. The Exirel label has been expanded to include SWD control on caneberries, and Mako and Malathion have received emergency use registration for this year again. The PHI for Entrust on bushberries is 1 day.
- When SWD is present in your crop use regular sprays, thorough, clean harvest, and immediate post-harvest cooling to less than 5°C or cooler.
- We have found SWD in June bearing strawberries this week, a crop where SWD has not historically been a problem. If you are still harvesting strawberries make sure you are not picking soft fruit, and consider renovating early to protect other crops. Protect nearby raspberries with regular sprays.
- Be on the lookout for brown marmorated stink bug (BMSB) adults and nymphs in susceptible crops!
Links to weekly updates from other regions:
For more information:
Toll Free: 1-877-424-1300