kwanza trees-2

Asked April 23, 2016, 7:51 PM EDT

Have already submitted a question as to what our problem is for dying trees, which by the way are 3-4 years old and 10-15 feet tall. I have read farther and it is fairly evident it is P. syringae since on further inspection open cankers on the trunk of the trees are evident, After inspection of some of the remaining trees cankers are also evident but have not killed the entire tree and just a branch or two. We also have two flowering cherry trees that are 10 plus years old and well established but show evident signs of old cankering (perhaps 2-3 years ago), 2 new questions: 1. Can anything be done for the younger trees (both the affected & not) such as white paint, copper solutions (we have bees), etc. or remove & burn them if they die? 2. Should we do anything with the older trees (base trunks are 10-12 inches across)? Again, Thank you..

Linn County Oregon cherry trees horticulture

3 Responses

Thank you for your questions. Once a tree is infected there is very little that can be done for it. This doesn't mean that all infected trees will die. Cankers stop their growth in the summer and sometimes they do not resume their growth again in the fall. These trees may survive. If the cankers are on a lateral branch, it is possible to prune out those branches along with the canker. If however, they are located on the trunk, not much can be done. Older trees are more likely to survive. Once cherry trees become 8 years old they obtain some resistance to bacterial canker. Again, there is not much that can be done except to prune out and lateral branches with evidence of canker. Other steps that can be taken to help the trees to recover is to would be to do any pruning in the dry period of summer to early fall and keep the trees as healthy as possible with proper (not excessive) irrigation and fertilization.

Thank you. If the bacterium is in the soil is it possible to eliminate the bacterium since we would like to plant new trees in the space. All effected cankers are on the center of the trunks not the limbs. Should we white paint the effected (and all tree's) to help protect the cambium layer? Any ideas for more resistant trees that could be used since they will be used along a driveway (10 feet away) where their root structure won't create problems?

This particular bacteria is everywhere. It colonizes grasses and weeds, and infects many species of trees besides cherries. You will not be able to eliminate it. Painting the trunks of newly planted trees with a white latex paint can be helpful in some situations. It's not a bad idea. I'm not aware of any resistant varieties. Unfortunately, with this disease your options are limited to what I mentioned previously. Don't prune in the rain, summer or early fall pruning only, proper irrigation and fertilization.