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I received a call this past week asking what was the little black bug in their raspberries and was it harmful to the plant? The bug is a picnic beetle and it doesn't harm the plant but it surely can be a pain when the beetle is crawling out of a picked berry.

The Picnic beetle is a type of sap beetle and is in the family Nitidulidae. They are about one-fourth inch long, oval shaped, and black with four orange spots.

They overwinter as adults and are active from spring and through the summer. We most commonly see them in gardens during mid to late summer and fall. They are attracted to all kinds of fermenting smells including overripe and rotting fruits and garbage. They are much like the Asian beetle in that unless the fruit or vegetable is soft it needs something else like a bird or injury before it can penetrate the skin. Many of us are anxious to pull back the husk on the sweet corn to see if it is ripe. That's all the picnic beetle needs to get into the cob and suck out the juice from the corn kernels.

We mostly see them on overripe berries, corn, tomatoes, and melons. They usually don't attack healthy fruits and vegetables, again because they can't gain entry.

There are many reasons why the skin of the tomato breaks. It could be because the fruit grew too fast, blossom end rot, injury due to weeding or birds, etc. All of these reasons and more are an invitation for the picnic beetle to enter.

Wireworms will come up through the ground and bore holes in healthy melons leaving the door open for picnic beetles to enter the melons, unnoticed. When you open up the melon it has been ruined by the beetles.

Their favorite diet is overripe strawberries and raspberries. They are soft and fermented and make a perfect meal. It's not very appealing to have one crawl out of a berry that you are intending to eat with your cereal. Nor is it good to be selling berries with picnic beetles in them.

The best way to keep them away is to avoid attracting them into the area from the beginning. Practice good sanitation by picking the fruits and vegetables as they ripen. Remove any damaged, overripe or rotting produce on a regular basis. Once they are drawn to your garden, they are difficult to get rid of.

Insecticides to control the picnic beetle are not very effective. While you can kill the beetle that is present, the control is not long lasting. Once you do spray, you can't pick the fruit or vegetables for a length of time. In the long run, it is better to use good sanitation practices to keep the picnic beetles out of your garden than to depend on insecticides later on.

The Chisago County Master Gardeners can be contacted by calling 651-213-8905.

Our office is located at the Maple Commons Building in North Branch at 38794 6th Ave.

If you have a Lawn and Garden question for the Master Gardeners, please call 651-213-5430 and go to option 4. Leave your question on the voice mail and someone will contact you shortly.

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