East Michigan fruit crop report – July 21, 2017

Spotted wing Drosophila jump to high numbers. Protecting ripening fruit is critical.

Spotted wing Drosophila (SWD) numbers have jumped from moderate to high numbers in the last few days, with some fruit infestation being found. Blueberry and summer red raspberry harvest continues, with tart cherry harvest winding down at many farms.

Over the last two weeks, SWD numbers caught in traps in the region have climbed from single to double digits. However, in the last few days, the numbers have jumped into the triple digits. More importantly, I have a good number of reports of SWD infested fruit in both blueberries and summer red raspberries.

This increase in SWD trap catch normally comes in early August. Why are numbers so high this season? It is hard to say for certain, but some of the answers lie in the abundance of wild hosts outside berry fields.

Protecting ripening fruit is vital at this time. As more fruit approaches harvest and the number of SWD increase, it becomes harder and harder to protect fruit. Tight spray schedules are needed to control SWD. More frequent harvest schedules will reduce the amount of time berries are exposed to SWD. The longer ripe fruit stays in the field, the more likely it is to be attacked by SWD.

If you are still harvesting tart cherries, they are also prone to SWD infestation and controls need to be applied.

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