Northwest berry Foundation

Management Detail

Box Elder Bug

in Blackberries

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Latin name: Boisea rubrolineata


Reason for Concern
1) A potential Harvest contaminant.
2) Egg laying on flowers can result in poorly formed fruit.
3) Large populations during fruit ripening can result in deformed druplets (Dry Cell symptoms) due to feeding.

Adults are oval-shaped and approximately 0.5" long. They're black in color with 3 red lines on their thorax and on the edges of their wings. Adults feed almost exclusively upon the seeds of the different species of Acer trees. However there has been some recent discussion that high populations can feed on drupelets by sticking their probuscuses (long, thin feeding tubes)into individual drupelets. These damaged drupelets then take on secondary infection causing shrunken, brown, scabby lesions on dropelets. Nymphs are smaller, less-elongated, wingless versions of adults and are entirely bright red. Oval-shaped eggs are clustered together and are orange to brown in color.

Life Cycle:
Adult Box Elder Bugs overwinter in protected places (often times within the crevices of heated, man-made structures). In early spring, as buds begin to break, females will come out of their winter cover, mate, and lay eggs. Hatched nymphs feed on leaves through summer until the develop into adults and move into trees to feed on seeds. As temperatures begin to decrease in the fall, Adults move back into their sheltered locations to hibernate. Only 1 generation per year.



  • Beginning in early spring, take 5 beating tray samples from 4 random locations per 10 acres of field. Record the number of Box Elder adults that are found.
  • Examine Leaflets and flowers for clusters of oval-shaped, orange eggs.
  • During fruit coloring, watch for adults on fruit and make not of any individual or cluster of drupelets that are shriveled, dried, tarnished colored (see Dry Cell for further description).
  • During harvest, train workers to pick out any Box Elders and record the numbers and locations in which they are found.
  • As the economic impact of Box Elder Bugs is unknown, there is no specific threshold for treatment.

Cultural Controls:

  • The only effective control for Box Elder Bug is the removal of host tree species (female Box Elder trees, Ash, and Maple predominantly). As damage from this insect is very rarely economic, it is generally unnecessary to do this.


For information about chemical controls, check with our Pesticide Guide.


picture by T. Peerbolt

picture by T. Peerbolt


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