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What is this on my strawberries? #869868

Asked May 24, 2024, 2:06 AM EDT

Ripe strawberries have these on the underside - they’re like tiny little worms, minuscule, very active. On the soil below, too. How to treat? Thank you.

Josephine County Oregon

Expert Response

It is difficult to tell specifically what kind of creature is in your pictures, but they do look more like larvae than worms. To prevent pests from reaching your strawberry fruits, you can create a barrier by a cover of straw mulch so that the strawberries are not in direct contact with the soil. Sprinkling diatomaceous earth just around the plant bases is another idea.
Also consider, the larvae of the spotted wing drosophila (SWD), an invasive fruit fly species from East Asia. The female SWD uses a special egg-laying device called an ovipositor to make a small incision in a fresh berry and lay eggs deep inside, which are too tiny to see with the human eye. The larvae are generally harmless to consumers and don't negatively impact your health. However, the SWD can cause significant damage to crops.
Management of SWD can be challenging but is best achieved through a combination of detection, sanitation, and insecticides. The best control appears to be when gardeners destroy infested fruit to kill larvae, while using an insecticide to kill the adults at the same time.
Gardeners who are concerned about SWD should monitor for the presence of adults. Take a large clear plastic cup with a cover. Make several holes, 3/16 in diameter, near the top on one side of the cup. Larger holes will allow larger flies and other insects such as sap beetles to enter the trap, making detection of the SWD more difficult. The easiest way to make the holes is to heat a small (8 or 10 penny) nail, which can melt the right size hole in the cup. Pour one to two inches of apple cider vinegar into the bottom of the cup. You can then either add a yellow sticky card slightly above the vinegar or a little bit of liquid soap such as dish soap. Hang traps on branches in a shaded location near fruit. Replace the sticky card and apple cider vinegar bait at least once a week for SWD, disposing of the apple cider vinegar away from the trap location. Checking traps more often can be beneficial for early detection of adult SWD, especially early in the growing season.
Remove and dispose of all infested fruit to keep SWD numbers low. The larvae can be killed by microwaving the fruit, cooking the fruit or placing the fruit in a sealed plastic bag that will be put in the trash. Do not bury infested fruit or place fruit in a compost pile as the adults can still emerge.
Apply insecticides as soon as adults are caught in a trap. Repeat applications will probably be necessary; continue to monitor the trap throughout the growing season. Insecticides should be applied in the evening to avoid killing honeybees and other pollinators. Available insecticides to kill adult SWD are permethrin, carbaryl, malathion, spinosad and pyrethrin. Spinosad and pyrethrin are approved for organic production. Always read and follow labels when spraying pesticides, and follow the pre-harvest interval for all products.

Here are some publications you will find useful.
https://extension.oregonstate.edu/pests-diseases/insects/how-make-trap-catch-spotted-wing-drosophila-fly

http://msue.anr.msu.edu/news/potential_for_spotted_wing_drosophila_infestation_in_dropped_cherries


Hope this helps!!




Chris Rusch Replied May 24, 2024, 11:40 PM EDT
Thank you very much! 

Kate



On Fri, May 24, 2024 at 8:40 PM Ask Extension <<personal data hidden>> wrote:
The Question Asker Replied May 25, 2024, 12:29 AM EDT

thanks for contacting ask an expert!

Chris Rusch Replied May 26, 2024, 12:09 AM EDT

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