The Insect Responsible: Spotted Wing Drosophila
The insect commonly responsible for this is called the spotted wing drosophila (SWD). Unlike many fruit flies that prefer fruit that is already rotting, this species often targets healthy, ripening fruit still on the plant.
Adult SWD flies are tiny insects with red eyes and light-colored bodies. Male flies have distinct dark spots on their wings, which is where the species gets its name. Female flies have a specialized egg-laying organ that allows them to pierce the skin of firm fruit and deposit eggs inside. Because of this ability, they can affect crops such as strawberries, blueberries, cherries, and raspberries.
Why Salt Water Makes the Larvae Come Out
Many people soak fruit in salt water as a cleaning method. A common mixture is about one tablespoon of salt per cup of water. When berries are submerged, the salt changes the surrounding environment.
Through a process known as osmosis, the saltwater draws moisture away from the larvae. This creates stress for them, causing them to move out of the fruit and into the water. Once they emerge, they become visible to the naked eye.
Are These Larvae Harmful?
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