On a shady hillside in Scarborough, (a “reverse” ravine) under Black Walnuts, we have a large number of Black Raspberry bushes. These are supposed to be compatible. We started seeing orange rust a year ago (maybe 2) and now it is on many plants. I googled and found a site that says we have to remove the entire plant including roots which is likely to be impossible for us. I can cut the canes but getting the root out is a task. https://extension.umn.edu/plant-diseases/orange-rust-raspberry#:~:text=Arthuriomyces%20peckianus%20is%20the%20rust,the%20roots%20to%20the%20canes.
1. Do you have any other suggestions for dealing with the problem?
2. Should I dispose of the canes with city compost or put them in garbage? Thank-you.
Thank you for posting this question to the Toronto Master Gardeners.
The reference that you cite from the University of Minnesota Extension agency is a good one.
It suggest that: since orange rust can’t be cured, plants infected with orange rust should be dug up or killed.
- Examine black raspberry and blackberry plants in early spring, when the new primocanes are less than a foot high.
- At the same time look for any wild black raspberries that may be near the garden.
- Any plants with weak, thin shoots and pale yellow or green leaves should be dug up and composted or killed with herbicide.
- Always remove or kill infected plants in early spring before the new canes release powdery, orange spores.
Homeguides has an article by Sara Ipatenco, that describes in detail how to remove a raspberry patch. It seems detailed, and has good information: https://homeguides.sfgate.com/remove-raspberry-bushes-22142.html
Fungal diseases like orange rust, live in the soil for years so it is important to remove and destroy plants as instructed above. Do not re-plant raspberries into this part of the garden. Place all debris out for kerbside pick up with your other garden waste; do not put the canes in your home composter. The city composter is at very high heat and can destroy the fungus.
For more information on what can be grown in the vicinity of black walnut trees, maybe you wish to consult this Gardening Guide: https://www.torontomastergardeners.ca/gardeningguides/juglone-and-black-walnut-a-toronto-master-gardeners-guide/