There are small, white worms in my raspberries. What are they and how can they be controlled?
The small, white worms are likely the larvae of the spotted wing drosophila. Spotted wing drosophila adults are small, yellowish brown flies. Males have distinctive dark spots on their wings, hence the name spotted wing drosophila. Female adults have serrated, saw-like ovipositors and lay eggs in soft, ripening fruit. Spotted wing drosophila larvae are white, 1/8 inch long maggots.
Spotted wing drosophila feed on soft, thin-skinned fruit. Their preferred food choices are raspberries (especially fall cultivars), blackberries, and blueberries. However, they also feed on grapes, strawberries, cherries, and aronia.
Control of spotted wing drosophila is difficult. In the home garden, sanitation is the most practical control measure. Promptly harvest ripe fruit. Remove and dispose of over-ripe, damaged, or rotting fruit. Dispose of berries in a manner that prevents flies from emerging and reinfesting sound fruit.Insecticides are a possible control option. However, most commonly available garden insecticides have preharvest waiting periods of several days, making their application to ripening fruit impractical. If you decide to use an insecticide, select one with a short preharvest waiting period (such as one day) and carefully read and follow label directions.