Blueberry Canker?

Question: Hello, I have a neighbor in my area that says I may have canker on my bushes. Can you confirm whether this is canker, and how I can prevent from getting it again? Thanks in advance! The first 2 pictures are of older bushes pirchased from Anderson Blues, last a 2 yr old bush.

responder: Leo Sherry  Replied May 03, 2023, 3:07 AM EDT
response: Hello! These do look like cankers. Cankers are localized areas of dead tissue. The symptoms most closely match Fusicoccum Canker (Godronia Canker) or Botryosphaeria corticis (with the first more likely), but I can’t be completely sure. The recommendations for control of both of these are very similar.  Some questions that will help narrow it down/confirm the diagnosis: Do you know what varieties of blueberry these are?Is only the newer wood affected?When did these spots appear?Were these plants stressed during the heat wave over the summer?  To control the problem and prevent it in the future, the affected branches should be pruned off and disposed of. Do not add them to your home compost. When pruning a diseased plant, be extra careful to sanitize your tools between plants so no pathogens are spread. Drip irrigation, as opposed to overhead watering, can help prevent the spread of fungal diseases. Resources: Blueberry (Vaccinium corymbosum)-Fusicoccum Canker (Godronia Canker) Blueberry (Vaccinium corymbosum)-Stem Canker Please let me know if you have any questions. Regards, Leo Sherry OSU Extension Master Gardener Volunteer

responder: The Question Asker Replied May 09, 2023, 5:13 AM EDT
response: Thank you foe getting back to me! The larger bushes are Liberty, which is one I bought from the Andweson Blues blueberry farm that is selling off their bushes from the property they have sold, and the smaller ones are Blueray from wilco last year.The older bushes are more eatablished and it is effecting one of the newer main trunks of the bush. If I cut it off it wouldn't have much left.Is there any kind of medicinal way to get rid of it? The effected branch is not a new shute, I believe it is a few years oldWhat would the effect in the plant be, if I left it? Will it completely kill the plant?Andrea PackardOn Wed, May 3, 2023, 12:07 AM Ask Extension <<personal data hidden>> wrote:

responder: Leo Sherry  Replied May 11, 2023, 4:08 AM EDT
response: Hello! Thanks for getting back to me. 'Liberty' was on the list of affected varieties for Fusicoccum canker. Cankers can harm the plant by completely girdling the stem. This stops the flow of water and nutrients, so the areas above it die. The whole plant won't necessarily die, just the areas above the canker that's all the way around the stem. It sounds like it would be unreasonable to remove all of the affected branches. I recommend trying to stop it from spreading with good sanitation of pruning tools. Preventing injury to the stems can also help because pathogens can enter that way. In a year or so, more shoots should come up that can eventually replace the older ones. If it is Fusicoccum canker, then no fungicides are registered for control.  If it is bacterial canker, some biological options (surface disinfectants) exist. Blueberry (Vaccinium corymbosum)-Bacterial Canker | Pacific Northwest Pest Management Handbooks lists two options. You'll want to scroll down to the "Biological control" section and look for the options with an H in a box after them. This means that they are available in packaging for home use. I hope this helps! Regards, Leo Sherry OSU Extension Master Gardener Volunteer