A friend of mine has a pretty large cherry tree and has suddenly started leaking sap. It's clear and abundant. Mostly in the crotches but one area on an upright branch. Also the leaves on the outer edge of the branches are shriveling. I dug up around the trunk and discovered a ton of large black ants and also some other flies hanging around. Any ideas or recommendations? He is kind of attached to the tree. Thanks.....
Crotch
fly
Leaves. Sorry, overexposed.
Doesn't look good. Not sure what the cause is, but I'd be surprised if it survives.
Resin
Yikes. Thanks, Resin.
Cherry trees (especially Prunus serotina) can have this affliction annually, and live long lives. I'd suspect some sort of borer has penetrated the bark, and the sap is exuded from these intrusions. But that's only a guess based on limited data.
Where's a picture of the whole tree? What species/clone of cherry is it? What kind of situation/conditions is it growing in? Have there been any unusual activities (construction), or climatic occurrences (like ice and/or snow loads) recently?
Those are some really good closeups, but more broad-based information aids in diagnostic assistance.
Gummosis can have three causes: mechanical injury, infectious disease, and borer. In this case it's apparently not mechanical. I don't suspect borer because there is no frass evident from the exit holes. In particular, it is rare for peach tree borer activity to occur more than a foot up from the base of the root flare. That leaves infectious disease as the culprit. Wounds that ooz amber colored gum are most often caused by Cytospora canker, a fungus. The other two possible causes are another fungus, Botryosphaeria dothidea and a bacteria called Pseudomonas. I would clear away some of the "sap" and look underneath for diseased tissue to confirm. The fungus gets into the tree through a wound. Sunscalded bark and winter injury to bark in narrow angled crotches are common entry points, as are improper pruning cuts and insect injury. The only treatment is to clean out the diseased tissue and allow the wound to dry. Purne out any small infected limbs. Do not paint or dress the cleaned areas or pruning cuts. Leave no ragged edges. Practice proper pruning techniques and good sanitation. Keep the tree watered and fed.
Would t'wer that only the peach tree borer afflicted the genus Prunus. Looking beyond a first glance reveals the following litany of pests of cherry bark, wood, and twigs:
Cambium miners; flatheaded apple tree borers; twig pruners; American plum borers; living beech borers; dogwood twig borers; blackhorned crickets; peach bark beetles; larger shothole borers; buffalo tree hoppers; ambrosia beetles; and leopard moths.
I asked about recent weather events, because those suggested could certainly have created mechanical injuries not evident to those unfamiliar with common diagnostic techniques. Ice/snow loads very often create cracks and splits while under the load, which "disappear" upon removal of the weight. Many trees fail later, with contributions due to these unseen damages to the bark and wood which close and are invisible to casual observation but serve as a smorgasbord of infiltration points to insects and disease.
Phytophthora is another common cause of stem cankers which create gum exudates.
So...this tree could have been mechanically damaged unbeknownst to observers of these few photos, infested by bacteria, fungi, or insects, and then displayed profligate gummy sap in response. Or any combination thereof.
Let's see some more pics.
By "mechanical" I meant hit with an axe or other type of human inflicted injury. Winter injury to the bark, especially in narrow angled crotches that causes a bark split, is, as I mentioned, one of the most common causes of wounds that allow entry points for fungal diseases. As I also mentioned, insect injury is another common route for infection, just not likely to be the peach tree borer.
This message was edited Aug 11, 2009 6:55 AM
I'm working on getting some more pics. I just have to get over there. Thanks for the info so far.
How's it going dybbuk?
hi, i still haven't gotten over there. he says that the tree seems to be looking pretty well and the leakage has stopped. i will try to get there this weekend to get a full shot of the tree. thanks for the nudge :)
