Cherry tree sap oozing

Our cherry tree has large amounts of sap running from all around the trunk and about 8 inches up every branch. I dug into a couple of the wounds and could not find any borers, but that is my suspicion. I had a cherry and a peach do the same thing, and it was borers. Should I dig more? What is your opinion?

The borer most likely to attack an otherwise healthy cherry tree is the peach tree borer which will be found in the bottom foot of the tree trunk. It will not be found boring into the branches. There are other borers that will be found in the branches but, if they are there, the tree will be nearly dead because these borers don't attack a healthy tree. In addition, you would have described the sap as coming out in little spirals from the holes left by the borers. From what you wrote, I suspect something other than this type of borers.

It is possible that there are peach tree borers damaging the tree at its base and causing the other problems you described. So, check for gummy sap and sawdust at the base of the tree. If that is there, peach tree borers are probably present. In that case, the borers may be causing death of the bark higher on the trunk by interrupting the flow of nutrients and water. Sap will be found oozing at the top of the dying bark.

Don't do a lot of digging into the bark looking for borers. This can do more damage than the borers. Some careful digging into the sap is okay. Cherry trees and related trees, such as plums, apricots, peaches, etc., will often develop "shields" of sap in response to injury. The injury can be due to freeze damage (in this case the sap shows up in the early summer), or it can be the result of physical wounding. Physical wounds can be due to wire tied around the trunk, mower damage, hail injury, or sun scald of the bark. Wounded areas are also subject to diseases, so that may also be a factor.

At this time, I would consider the factors listed above to see which can be eliminated. Keep the tree well watered, watering once a month through the winter, then see how it looks in the spring. It may recover if there is physical damage which is not too extensive. If there are borers at the base of the tree causing dying of the bark above, it will be necessary to treat for the borers.

Marisa Y. Thompson, PhD, is the Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, email: desertblooms@nmsu.edu, office: 505-865-7340, ext. 113.

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