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Tops of Raspberry canes cut off #759305

Asked June 30, 2021, 1:54 PM EDT

I planted a few different kinds of raspberry canes early summer in a raised bed. They have been growing well and starting to produce fruit. Then the last 10 days or so, several of the tops of the cane have been cut and are hanging from the cane. The cut is clean. The cut is just below the top leaves, often right under where the fruit is growing. I have lost a couple of dozen raspberries so far. Is it cut worm? Or something else? How can I stop or control it? Thank you, Brent Derowitsch

Hennepin County Minnesota

Expert Response

Raspberry cane borer, Oberea bimaculata Oliver feeds on the tender shoot tips of new raspberry canes. Six inches below the tips of the new primocane the raspberry cane borer cuts two rings about 0.5 inches apart into the stem. Remove the portion of the stem between the two girdles and throw it in the trash to control this insect. The following site has more information.

https://www.canr.msu.edu/news/controlling_raspberry_cane_borer

Pat M MN master gardener and TCA Replied June 30, 2021, 6:59 PM EDT

Thank you!  Your information is very helpful.  Soon after I sent you my first email, I took a closer look at the canes and noticed the double girdling on several of the canes.  I'm glad the control of the insect is easy and does not involve spraying.  I'm going out now to prune my canes.  With much gratitude, Brent

The Question Asker Replied July 02, 2021, 11:42 AM EDT

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