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Unwanted Pests in Your Raspberry Patch

University of Minnesota Extension, Stearns County News
July 8, 2015

Source:  Beth Berlin, Extension Educator-Horticulture
University of Minnesota Extension
Stearns, Benton & Morrison Counties

Unwanted Pests in Your Raspberry Patch
By Beth Berlin, University of Minnesota Extension

ST. CLOUD, Minn. (7/8/15) — July brings berry season, especially raspberries, and not only do we look forward to the tasty treat, but so do the bugs.  One common pest that will impact your delicious raspberries is the sap or picnic beetle.  These beetles are also known to impact other crops as well, but with some good garden practices damage and populations can hopefully be minimized.

Minnesota has several species of the sap or often called picnic beetles. They range in size from 1/8-inch to 1/4-inch. Depending on the species, they are mottled brown to black with one species having four distinct rust-orange spots on its wing covers. Another key identifying characteristic is the “knob” at the end of the antennae.

Sap beetles are known to do damage to raspberries, strawberries, tomatoes, corn, and muskmelon.  Often the sap beetles will be found on fruit or vegetables that were damaged by other insects, weather, or disease.  They are commonly found on overripe fruits or vegetables too. The pests overwinter in Minnesota, lay eggs, pupate and emerge as adults in June or July.

Best management practices include frequently harvesting your fruit or vegetables before they become overripe.  Remove and bury or dispose of any damaged, diseased or overripe fruit or vegetables.  Bait trapping is also an option.  Simply put a container with fermenting plant juices several feet outside of the garden and discard the content of the trap twice a week.  The trap’s juice can consist of stale beer, molasses-water, yeast-water, vinegar, or overripe fruit.

Spraying insecticides is impractical because the sap beetles are not active and impacting your fruit or vegetables until they are ripe and ready for harvest.  Spraying any insecticide would create a waiting interval before harvest is safe therefore making harvest at the prime time nearly impossible.  Typically good cultural practices with sanitation and trapping are adequate enough, however in severe infestations products containing carabryl or bifenthrin are options.  Be sure to carefully read and follow all directions, and do not consume crop until the harvest-waiting interval has passed.

Sap beetles can certainly cause a loss in appetite and be a nuisance, so take the upper hand on controlling these pests in your raspberry patches and other fruits and vegetable gardens this season with good management practices. For more information visit


Sap/Picnic Beetle. Photo credits: Tom Murray


Beth Berlin
Extension Educator, Horticulture
(320) 255-6169
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