Black Beetles inside raspberries

Asked August 28, 2013, 7:05 PM EDT

I have tiny black beetles with 4 tan spots on their backs that get inside the berry itself. Do you know what they are and how to get rid of them?

Boulder County Colorado trees and shrubs

1 Response

Thank you for contacting the CSU Extension Master Gardeners help desk. Based on your description, it sounds like you have Picnic or Sap Beetles. These beetles are attracted to ripening fruit and are best managed by removing all of the ripe fruit. Unlike the cane borer beetles, these beetles do not damage the plant; they are more of a nuisance. For additional information on the picnic beetle and other pests affecting raspberry plants, please see the link below.
Picnic or Sap Beetles: The most common picnic beetle (family Nitidulidae) is a small (ΒΌ inch long), black insect with four yellowish-orange spots on the back. Adult beetles are attracted to all types of overripe and decaying fruit. Although not attracted to ripe, undamaged raspberries, these can be damaged once picnic beetles are in the garden.
Damage: Look for the distinctively patterned adults on partially consumed, overripe raspberry fruits.
Control: Unlike most insect pests of raspberries, picnic beetles often reproduce outside of the raspberry patch and only fly into gardens when the berries become overripe. Proper sanitation is the best control of these beetles. Make sure ripe or damaged fruits are promptly picked to avoid attracting them.
Insecticides seldom control picnic beetles. Raspberries cannot be picked immediately after applying insecticides because there is a waiting period after the raspberries are sprayed. The waiting period is the number of days required between insecticide application and harvest. During that interval adult beetles continue to fly into the patch if attractive fruit is present.
Caution: Always use insecticides strictly in accordance with label precautionary statements and directions. The label should state that the insecticide may be used on raspberries or generally on fruit. Raspberries are sometimes referred to as 'cane berries' on insecticide labels. Carefully observe the waiting period. Protect pollinators--do not spray raspberries or other fruits when they are blossoming. If suggestions in this publication contradict label recommendations, the label is the final authority on how to use that specific product.