Beetles include many species that feed on fruits. This feeding can lead to significant damage for home gardeners and commercial growers. While not all beetles consume fruit, certain species are known for their destructive impact on ripening produce. Understanding which beetles target fruits and their activity signs is valuable for protecting fruit crops.
Common Fruit-Eating Beetles
The Japanese beetle (Popillia japonica) is a well-known invasive species with a metallic green body and coppery-brown wing covers. They feed on foliage, flowers, and fruit.
Sap beetles, also known as picnic beetles, are small, oval, dark-colored beetles, typically 1/8 to 1/4 inch long, with clubbed antennae. They are strongly attracted to the sweet, fermenting odors of overripe or damaged fruits, where they can chew deep cavities. The strawberry sap beetle (Stelidota geminata) targets strawberries.
Plum curculios (Conotrachelus nenuphar) are weevils, about 1/4 inch long, distinguished by their prominent snout and four humps on their dark brown wing covers. Both adults and larvae damage stone and pome fruits. The green fruit beetle (Cotinis mutabilis), sometimes called the figeater beetle, is a large, metallic green beetle, up to 1 1/3 inches long, that also feeds on soft, maturing fruits.
Fruits They Target
Beetles are drawn to fruits by their sugar content and fermentation odors, especially as fruits ripen or become damaged. Many species prefer overripe, cracked, or injured fruits, as these conditions make the fruit more accessible and attractive. This includes fruits nearing harvest or those that have fallen.
Berries such as strawberries, raspberries, and blueberries are commonly targeted by sap beetles and Japanese beetles. Stone fruits like peaches, plums, cherries, and apricots are also highly attractive, particularly to plum curculios and Japanese beetles.
Apples are another common host, though damage varies by beetle species. Grapes, figs, tomatoes, and sweet corn are also consumed by various fruit-eating beetles. Thinner skins can influence a fruit’s vulnerability to beetle damage.
Identifying Beetle Damage on Fruit
Beetle feeding results in irregular holes or gouged areas on the fruit surface. Sap beetles create deep cavities, which can be confused with slug damage, though sap beetle holes are circular with soft, sunken edges.
Plum curculios leave distinctive crescent-shaped scars on fruit, made by the female when laying eggs, and small, round feeding holes. Larval tunneling inside the fruit can lead to premature fruit drop. Japanese beetles cause shallow, gouged patches on fruit, and in severe cases, can consume entire soft fruits.
Another indicator of beetle activity is frass, the excrement left by feeding larvae or adults. Frass appears as sawdust-like material, powdery residue, or small pellets, often found within tunnels or extruded from entry holes. Observing these types of damage and associated frass can help confirm the presence of fruit-eating beetles.