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Oozing sap on peach trunks and branches could be caused by several things.

Peach Gummosis

Do your peach trees have some gummy looking sap exuding from the trunk? Gummosis is the term for the symptom of gummy sap oozing from the trunk and branches. It is not that unusual and can have several causes. Chemical, physical, insect, disease, or stress damage to the trunk can cause this symptom. Before you worry too much about it, you need to rule out the most destructive causes.

Insects

There are two different peach borers that bore into trunks and scaffold branches that can cause this. Make sure there is no bore hole and frass beneath the sap to rule out these problems. The Peach Tree Borer attacks trunks, and the Lesser Peach Tree Borer attacks the major branches. More information on borers.

Water

Too much water on the trunk can cause damage that results in gummosis. Irrigation heads that put water on the trunk and high weeds that hold moisture in around the trunk are culprits. Make sure your irrigation head shoots water around the tree but does not put water on the trunk. Control the weeds around the trunk but do not use glyphosate herbicide. Glyphosate, the common ingredient in Roundup®, is easily absorbed through the thin bark of peaches and can make the problem worse. Water stressed or poorly managed orchards are also at greater risk.

Physical Damage

Physical stress to the trees can cause microscopic injury to the wood that results in gummosis. Wind is not kind to peaches, the fruit or the branches and trunks. Hurricane Irma shook a lot of trees around and they are showing the symptoms now. However, if the trees are growing well and you have eliminated other stresses, this does not mean the loss of your tree. Correct any problems that can lead to fungal infection and a worsening of the problem.

Fungal

Botryosphaeria is a fungus that can enter wounds or even the lenticels on peaches. Trees that have damage from all the above mentioned problems can also become infected with this fungus, making the problem much worse. This fungus causes raised blisters at infected lenticels leading to necrotic cankers that ooze sap in the second year. Large cankers will coalesce, killing branches or the entire tree. More information on fungal gummosis.

Management

Reduce stress and practice sanitation by removing and destroying diseased wood. Avoid pruning immediately before or after a rain or irrigation event when leaves are wet. Avoid pruning water- and nutrient- stressed trees. Prune trees with gummosis last. Clean pruning tools after pruning an infected tree with mild bleach, rubbing alcohol, or quaternary ammonium solution to sanitize tools. Fungicide applications to the trunks of young trees may help to suppress fungal infections. The latest fungicide recommendations.

10 Comments on “Peach Gummosis

  1. Most of the peaches are affected by gummosis- can healthy looking portions of the fruit be eaten?

    • If the fruit have “gum” exuding from them, it is not gummosis, but a response to damage. Stink bug feeding damage usually results in clear gum oozing out of the feeding site. This may cause a deformed fruit depending on when the damage occurred. Healthy portions of the fruit are fine to eat.

        • Gum coming out of the fruit is caused by physical damage to the fruit – usually by an insect. Stink bugs and leaf-footed bugs can both cause this symptom from their feeding injuries. You will need to protect the fruit from damage to keep the gum from oozing from the fruit.

        • If the gum is already coming out, it is too late. However, in future you may consider controlling for insects or bagging the fruit. See Bagging as an Alternative Insect and Disease Management Tool presentation – it is a pdf, so you will have to Google it to get it, or ask me and I can email to you.

        • You have to protect the fruit before any damage is done to it. That would mean bagging or spraying proactively before damage occurs. Once damage has occurred, there is nothing that can be done to stop it.

  2. I’m in Ohio surrounded by fields and last month the farmer sprayed what I believe was 2, 4 D on the beans. I have major drift damage on pretty much everything in my yard. I have five very young peach trees and two were particularly damaged from this. I have a Flamin’ Fury that has lost almost all of its leaves and the new growth is dried and shriveled up, but I also have a Red Haven that is oozing sap like crazy. (There’s also a plum that is oozing, but this peach is the one that has me boggled) It may have had issues last year and I didn’t actually realize it, but now it is oozing sap everywhere. There are multiple spots on the trunk, the crotch seems to be weeping and even in all of the branches there are little spots of gum. Is it possible that this is a reaction to the herbicide? Or do I have something more serious going on with this tree? It is so close to the other trees that I’m worried to even keep it there in case it is actually bacterial… I’m thinking more and more that it has to do with the spray because I noticed a few small gummy spots on a couple of the other trees (but nothing huge like what is going on with this Red Haven)

    I’ve been googling for days, I asked the nursery I got the trees from, I asked another local nursery and basically I can’t get an answer for this specific question. One just said ‘peach borer’ (but I’m not sure what the holes are supposed to look like and… I don’t think there are any?) and otherwise I’ve gotten “we don’t know” and either general information about bacterial canker and how to sue for drift damage… 🙁 I just want to know what is going on with this tree and if I need to remove it to protect the other ones…

    • This is a difficult issue. Herbicide drift could cause the leaves to curl up and fall off. 2,4-D is a synthetic auxin (plant hormone) that will cause new growth to curl up and be deformed. Leaf fall could follow that. Have you asked the farmer what he sprayed? It could have been a mix or some other chemical. 2,4-D probably would not have been sprayed on beans – it is specific to kill broadleaf plants, which means the beans would have been affected.
      Herbicide damage could cause gummosis as you describe and some cultivars may be more sensitive than others or some may have been closer to the drift. Borers can also cause localized gummosis – if you pick off the ball of gum there will be a hole underneath it. Different borers attack different parts of the tree – some may be right at the soil line, some on the trunk, and some on the bases of the scaffold branches. A tree that is oozing gum all over is not likely to be caused by borers. Bacteria and Botryosphaeria could also cause this type of gummosis. Is it possible to take a sample in to your local extension office? Botryosphaeria will cause a brown discoloration in the wood and you may be able to see this if you cut off a twig. For your peace of mind it may be better to take the Red Haven out – if it is oozing that much sap it is not a healthy tree, regardless of what caused the problem. You may be able to cut it up and check it out more carefully when you do this to determine the issue.

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