Hello Fred, 

Thanks for reaching out! Upon further inspection of the photo you submitted, it looks like you may be experiencing raspberry cane borer. 

Raspberry cane borer is a beetle pest that feeds on raspberries. The two rings you see in the photo you sent in are a sign of the raspberry cane borer - the female punctures holes in the canes and then lays eggs between the rings. 

The good news is that raspberry cane borer is quite easy to control. When you see canes that are wilting or dead near the top, look for the puncture holes I mentioned above and cut the cane about 2 inches below the holes. Burn the cuttings to kill the larvae and eggs. Insecticides are usually unnecessary to control raspberry cane borer. 

More helpful information can be found here: 

https://blog-fruit-vegetable-ipm.extension.umn.edu/2021/10/raspberry-cane-borers-what-you-can-do.html

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

Good luck!