What's That Bug? does not endorse extermination

Black beetle with retractable stinger
July 7, 2010
We found this bug on the side of a maple tree. It is about two inches long not measuring what looks like a stinger that it can retract. It doesn’t move much and looks impressive. We looked all through the beetle pictures and couldn’t find a match. Can you help us?
Thanks!
Walnut Hill Gang
Natick MA

Broad Necked Root Borer

Dear Walnut Hill Gang,
Your beetle is a female Broad Necked Root Borer,
Prionus laticollis.  The stinger is actually the ovipositor of the female and she uses her ovipositor to deposit eggs.  According to BugGuide:  “Eggs are inserted into ground (or under litter) in groups. Larvae tunnel downward to feed on living roots of a variety of trees and shrubs. At first they may feed on bark, but then proceed to hollow out small roots. Pupation occurs in spring, about 10 cm under the ground. Life cycle probably three years.

Broad Necked Root Borer

What's That Bug? does not endorse extermination
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2 Responses to Female Broad Necked Root Borer

  1. CC says:

    Hi helpful bug friends,
    I have these beetles in my back yard. Will they damage my trees (which are huge and beautiful)? Are they damaging like emerald ash borers? What should I do, if anything?

    • bugman says:

      According to BugGuide: “Adults eat foliage, sometimes damage fruit trees, grape vines. Life Cycle Eggs are inserted into ground (or under litter) in groups. Larvae tunnel downward to feed on living roots of a variety of trees and shrubs. At first they may feed on bark, but then proceed to hollow out small roots. Pupation occurs in spring, about 10 cm under the ground. Life cycle probably three years.” Losing some roots should not be detrimental to the life of a healthy tree.

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