Marionberry issue - Ask Extension
Is this cane borer damage? It first appeared last year and is significantly worse this year despite culling effected canes
Knowledgebase
Marionberry issue #926464
Asked March 21, 2026, 5:51 PM EDT
Is this cane borer damage? It first appeared last year and is significantly worse this year despite culling effected canes
Lane County Oregon
Expert Response
Hi Joel,
The damage to the raspberry canes could be the raspberry crown borer. You can cut open one of the bulges and look for little whitish larva. This is one of the main pests to raspberries in our area.
In addition, you could have a fungal or bacterial disease that got in from the splits in the cane.
I am attaching a link on growing raspberries at home. It is quite long but has info on cane borers that have been found in Oregon: https://extension.oregonstate.edu/catalog/ec-1306-growing-raspberries-your-home-garden
These borers are the main cause of the swelling. They need to be cut out and put in the trash.
Here is another link on the crown borer. Adults look that yellow jackets:
https://extension.usu.edu/planthealth/ipm/notes_ag/fruit-rasp-crown-borer
And one more with the bronze or rose stem borer that likes roses and raspberries: https://blogs.oregonstate.edu/mgmetro/2017/11/01/rose-stem-girdler-new-pest-caneberries-roses/
Most of the information is for cultural changes. Once inside the cane, sprays do not work.
I hope this gives you a better understanding of the issue.
The damage to the raspberry canes could be the raspberry crown borer. You can cut open one of the bulges and look for little whitish larva. This is one of the main pests to raspberries in our area.
In addition, you could have a fungal or bacterial disease that got in from the splits in the cane.
I am attaching a link on growing raspberries at home. It is quite long but has info on cane borers that have been found in Oregon: https://extension.oregonstate.edu/catalog/ec-1306-growing-raspberries-your-home-garden
These borers are the main cause of the swelling. They need to be cut out and put in the trash.
Here is another link on the crown borer. Adults look that yellow jackets:
https://extension.usu.edu/planthealth/ipm/notes_ag/fruit-rasp-crown-borer
And one more with the bronze or rose stem borer that likes roses and raspberries: https://blogs.oregonstate.edu/mgmetro/2017/11/01/rose-stem-girdler-new-pest-caneberries-roses/
Most of the information is for cultural changes. Once inside the cane, sprays do not work.
I hope this gives you a better understanding of the issue.
