The “worms” found in cherries are almost always tiny fly larvae, and they’re more common than most people realize. Two species are responsible for the vast majority of infestations: the western cherry fruit fly and the spotted wing drosophila. Both lay eggs just under the skin of ripening cherries, and the larvae feed inside the fruit as it matures. The good news is that you can detect them before eating, and a simple saltwater soak will draw them out.
What the “Worms” Actually Are
Cherry worms aren’t true worms. They’re the larvae of small flies that target soft-skinned fruit. The western cherry fruit fly is the larger of the two culprits. Its adults are about 5 mm long with distinctive dark bands on their wings. The spotted wing drosophila is smaller (2 to 3 mm) with red eyes and, in males, a telltale dark spot on each wingtip. Both species produce small, white, cylindrical larvae with black mouthparts that grow up to about 3.5 mm long.
Female flies pierce the cherry skin with a specialized egg-laying organ and deposit eggs just beneath the surface. The spotted wing drosophila has a serrated version of this organ that can cut through the skin of intact, firm fruit, which makes it particularly problematic. Once hatched, the larvae of the western cherry fruit fly burrow toward the pit and feed for 10 to 21 days before boring out. Spotted wing drosophila larvae tend to feed more broadly through the flesh, and multiple larvae can inhabit a single cherry.
Cherries become vulnerable to egg-laying once they ripen to a salmon-blush color. Green fruit won’t be attacked. The window of susceptibility runs from that first blush of color until the fruit becomes too soft or falls from the tree.
External Signs to Look For
Infested cherries often show subtle but visible clues on their skin if you know what to look for. The earliest sign is a tiny pinhole on the surface, sometimes called a “sting,” where the female fly pierced the skin to lay an egg. In early infestations, this hole is extremely small and easy to miss at a glance.
As larvae begin feeding inside, a dark, circular discoloration forms beneath the entry hole. This darkened area grows as the damage progresses. Over time, the holes become larger and more jagged as larvae grow in size. You may also notice localized soft spots on otherwise firm cherries, or areas where the skin looks slightly sunken or depressed. When the mature larva of the western cherry fruit fly exits the fruit, it creates an obvious exit hole that’s much larger than the original entry point.
If you’re sorting through a bag or bowl of cherries, set aside any that have visible pinholes, dark spots beneath the skin, unusual softness in one area, or any sign of leaking juice where there shouldn’t be damage.
The Saltwater Soak Test
The most reliable home method for detecting larvae is a saltwater soak. Michigan State University Extension recommends dissolving 1 cup of table salt into 1 gallon of water. Place your cherries in this solution and let them sit for at least 30 minutes. Soaking for a full hour improves the chances of detection but isn’t always necessary.
The salt concentration creates an environment that forces larvae to leave the fruit. After the soak, check the water for tiny white larvae floating on the surface or resting at the bottom. Also inspect the cherries themselves for any larvae that partially emerged but didn’t fully detach. Rinse the cherries thoroughly in fresh water before eating.
This method works well for both species of larvae. It won’t reveal eggs that haven’t hatched yet, but those are far less likely to cause noticeable problems. If you find even a few larvae in a batch, it’s reasonable to assume more cherries in that group may be affected, since flies tend to lay eggs across many fruits in the same area.
Cutting Cherries Open
If you’d rather skip the soak, you can slice cherries in half and inspect them visually. Look for small white larvae near the pit (where western cherry fruit fly larvae tend to concentrate) or throughout the flesh (more typical of spotted wing drosophila). You may also see brown, mushy tunnels through the flesh where larvae have been feeding. Healthy cherry flesh should be uniformly colored and firm for its ripeness level.
This approach is practical if you’re checking a small number of cherries but obviously doesn’t scale well to large quantities. For bigger batches, the saltwater soak is far more efficient.
Are Cherry Worms Harmful to Eat?
Accidentally swallowing a cherry larva or two is unlikely to cause serious harm, but it’s not entirely risk-free either. Flies can pick up bacteria like Salmonella and E. coli from the environments they visit, and larvae developing in contaminated fruit can carry those bacteria. Eating contaminated larvae could lead to symptoms of bacterial food poisoning.
In rare cases, ingesting fly larvae can cause intestinal myiasis, a condition where larvae survive temporarily in the digestive tract. Symptoms can include abdominal pain, nausea, and vomiting. This is uncommon with the small fruit fly larvae found in cherries, but it’s a reason not to dismiss the issue entirely. Most people who unknowingly eat a larva or two in a cherry experience no symptoms at all, but minimizing the risk through inspection makes sense.
Reducing the Risk Before You Eat
Refrigerating cherries promptly after purchase slows larval development significantly. Cold temperatures (around 37°F or 3°C) can halt larval growth and eventually kill young larvae over several days of storage. This won’t remove larvae already present, but it prevents them from growing larger and causing more internal damage to the fruit.
If you’re picking cherries from a backyard tree, harvest them as soon as they’re ripe rather than letting them hang. The longer ripe fruit stays on the tree, the more opportunity flies have to lay eggs. Fallen fruit on the ground is a breeding ground for the next generation of flies, so clearing it away helps reduce future infestations.
Commercially sold cherries are typically inspected and may be treated to reduce infestation rates, but no process eliminates the risk entirely. A quick saltwater soak before eating any cherries, whether store-bought or homegrown, is the most practical way to catch what visual inspection might miss.