Weekly Fruit Update - August 10, 2022
UNIVERSITY OF MINNESOTA EXTENSION - www.extension.umn.edu
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| Japanese beetle trap counts have declined from their peak in mid-July. Image: UMN FruitEdge |
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| UMN entomologists check SWD traps weekly at 4 locations to reveal how populations change throughout the season. Image: UMN FruitEdge |
Apples
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| Zestar! fruit ripening in Minnetrista, MN. Photo: Annie Klodd |
Because I was traveling for strawberry and grape projects in the first half of this week, I was unable to do my usual Wednesday apple orchard scouting. However, here are some things to keep in mind for this week:
- Brown marmorated stink bug: Keep an eye out for this invasive pest in your apple orchard. It is fairly new to Minnesota and is spreading. They feed on the fruit directly and can decrease marketable yield of apples. Sightings are common in the Twin Cities metro and are occurring in other counties as well. If you live outside of the 7-county metro area, please report sightings of BMSB. Grower reports help us and MDA know when and how to deliver management recommendations. Find more information here.
- Apple maggot and codling moth are still active. Using monitoring traps is still the best way to know if and when to spray.
- First Kiss harvest will start in the next couple of weeks. When harvesting this variety, remember that they do not ripen all at once, and unripe First Kiss are quite tart. Read this article on how to tell if they are ripe.
- Cracking: If you experience cracking on fruit, it was most likely from the rain we had over the weekend, which followed an extended drought period.
Grapes
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| Side netting has been applied to VSP vines at Whitewater Wines, LLC in southeastern MN. Photo: Annie Klodd |
Across the state, grapes are deep into veraison now. Growers are applying their netting and have begun playing bird call recorders (if using them). Begin testing early varieties for brix and pH to make sure they are harvested at the right time.
Read this fact sheet for ways to optimize your bird control methods.
If you had planned to do a petiole nutrient test at veraison, this week is the last chance to do that. The benchmark values that we compare with the test results to determine nutrient deficiencies are based on measurements at bloom and veraison; therefore tests should be taken at those two times. Results from after veraison cannot be interpreted reliably. I was at a vineyard taking petiole samples for a project today (Wednesday) but I would not have wanted to wait any longer, as veraison was almost complete in all varieties.
The main diseases to watch for include powdery mildew, downy mildew, and botrytis. Symptoms of black rot are visible on the clusters now, in the form of mummified berries, but new black rot infections are unlikely.
Strawberries
This is peak season for day neutral strawberries. Expect to be harvesting daily for the next several weeks. Pick berries as soon as they ripen (the outside is fully red) to get them before something else does.
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| Picnic bug and its feeding damage on a day neutral strawberry. Photo: Annie Klodd |
Diseases and pests to watch for in strawberry:
- Anthracnose: This fruit rot disease favors warm, wet weather. Therefore it is a potential issue for day neutral strawberries in the late season. I spotted what looks like anthracnose on some berries today.
- Picnic beetles
- Slugs
- Tarnished plant bugs
- Stink bugs
- Spotted wing drosophila
As always, the Fruit Pest Management Guide is the most complete place to read up on pesticide options for the insects and diseases listed above. The reason we do not usually list pesticide options here is that products do change over time, and these articles live on the web forever. If you cannot find a suitable option in the MWFPM Guide, please contact Marissa Schuh or me, and we can assist.
