Raspberry Shoots Wilting/Dying - Ask Extension
Hello!
In my home garden, I have (4) 30'-40' long rows of raspberry plants, about 5'-6' apart. Probably 5-7 years old. I have a brand new problem t...
Knowledgebase
Raspberry Shoots Wilting/Dying #870564
Asked May 29, 2024, 10:53 AM EDT
Hello!
In my home garden, I have (4) 30'-40' long rows of raspberry plants, about 5'-6' apart. Probably 5-7 years old. I have a brand new problem this year:
New shoots, starting from ground level, either at base of existing plant, or new runners, ranging from a few inches to a foot high, droops over and eventually turns black. It's not happening to all new growth, even on the same plant, nor on new growth further up the existing canes.
I have gone thru at least 3 times and removed any affected growth, and even tried spraying the affected plant base with a copper fungicide, about a week ago, but it's still happening.
I would greatly appreciate any help and information you could provide, as to what's causing this, and what I can do to stop it.
Thank you!
Washington County Vermont
Expert Response
Hello Kristina:
The plant pathologist took a look at your photos, and following is what she said:
I am not sure what is going on. They should cut open the affected
section and make sure there is no borer in there. The traditional damage from the borer may not be evident from her pictures. Take a look at this info and pictures: https://extension.unh.edu/resource/raspberry-cane-borer-fact-sheet
The plant pathologist took a look at your photos, and following is what she said:
I am not sure what is going on. They should cut open the affected
section and make sure there is no borer in there. The traditional damage from the borer may not be evident from her pictures. Take a look at this info and pictures: https://extension.unh.edu/resource/raspberry-cane-borer-fact-sheet
Hello again, and thank you for such a quick reply.
I'm not seeing any of the typical sign of the cane borer, as shown in the photo you referenced, ie the 2 rings of puncture marks.
I did cut open a number of drooping shoots, and found no borers. However, inside some (but not all), on a cross-section, I did see a tiny brown spot, no bigger that the tip of a pin. Not sure you can see it in the attached photo. Also, several of the shoots had a clear brown "track" inside (photos attached), so I guess there must have been one inside at some point?
Assuming that cane borers are the cuplrit, despite the lack of those telltale rings, can I get rid of them? Is there an effective spray I can try, or is my best bet to just keep removing infected shoots? I've already filled at least 3 sheetrock buckets with damaged shoots that I've cut off, so I'm guessing that won't bode well for next year's crop?
Thank you again for your help!
Sincerely,
Kristina Foster
Hello Kristina:
The plant pathologist took a look at your latest images and following are her recommendations:
Yes, something was in there. There is a raspberry cane maggot that is a lot smaller but can cause this damage. The pictures in the factsheet look like yours! https://extension.unh.edu/resource/raspberry-cane-maggot-fact-sheet#:~:text=The%20maggot%20hatches%20from%20the,lot%20like%20a%20house%20fly%E2%80%A6
The best thing is to clip out and destroy the infested plants below where you see the browning inside. Insecticide sprays would be too tough to get the timing right, so keeping up the vigor of the plants from proper thinning, pruning and fertilizing and getting rid of infested tissue is best.
Growing raspberries in the home garden | UMN Extension
I hope this information is helpful.
The plant pathologist took a look at your latest images and following are her recommendations:
Yes, something was in there. There is a raspberry cane maggot that is a lot smaller but can cause this damage. The pictures in the factsheet look like yours! https://extension.unh.edu/resource/raspberry-cane-maggot-fact-sheet#:~:text=The%20maggot%20hatches%20from%20the,lot%20like%20a%20house%20fly%E2%80%A6
The best thing is to clip out and destroy the infested plants below where you see the browning inside. Insecticide sprays would be too tough to get the timing right, so keeping up the vigor of the plants from proper thinning, pruning and fertilizing and getting rid of infested tissue is best.
Growing raspberries in the home garden | UMN Extension
I hope this information is helpful.
Hello Again,
Bingo! The latest factsheet you sent describes it exactly.
I'll continue to remove the infested shoots as I have been, and hope for the best.
Thanks again for your help!
Sincerely,
Kristina Foster
Your welcome, Kristina! I hope your plants are able to recover and produce a nice harvest of fresh raspberry's!
