Small fruits, tree fruits, tomatoes, and sweet corn are susceptible to picnic beetle damage.
The picnic beetle is black with four prominent orange or yellow spots on the wing covers, which are shorter than the abdomen. The larvae are active white to cream-colored worms with brown heads. They pupate in the soil.
Damage Caused by Picnic Beetles
The sap beetles fly to ripening or damaged apples, strawberries, raspberries, watermelons, muskmelons, corn, tomatoes, etc. The beetles bore into the fruit and makes it unfit for human consumption. The picnic beetle tends to attack damaged and overripe or decomposing plant tissues. It attacks undamaged ear corn silks and ripe fruits. They tend to congregate in areas where fruit and vegetable materials are present.
Life Cycle of the Picnic Beetle
- The insects may winter as larvae or adults in decaying vegetation, debris, and fruit buried in the soil.
- They emerge in the spring and lay their eggs on spoiling or rotting vegetation.
- Later, they also lay eggs in the silks and kernels of damaged corn.
- The larvae feed in this decaying material until they are full grown, then they drop to the soil to pupate.
- There are two or more generations each year.
Management of Picnic Beetles
Harvest the fruits as soon as they ripen, and remove any damaged or overripe fruits and vegetables from fields and gardens. Insecticides can be used to manage beetles.
Commercial: Use traps/baits with scents of overripe fruits to monitor and discard the traps as soon as they are filled with the picnic beetles.
Contact your county Extension office for current pesticide controls.