The insect most often responsible is known as the spotted wing drosophila (SWD). Unlike many fruit flies that prefer overripe or decaying fruit, this species frequently targets fresh, ripening fruit still on the plant.
Adult SWD flies are tiny with light-colored bodies and red eyes. Males have noticeable dark spots on their wings, which is how the species got its name. Female flies possess a specialized egg-laying structure 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 Appear
Many people use salt water as a method to clean fruit. A common mixture is about one tablespoon of salt per cup of water. When berries are submerged in this solution, the salt alters the surrounding environment.
Through a process called osmosis, the saltwater pulls moisture away from the larvae. This creates stress for them, prompting them to leave the fruit and move into the water, where they become visible.
