Organic Answers Column - February 14, 2024 - Gummosis
Fruit Trees Oozing Sap - Gummosis
Question: I have a cherry tree that is leaking sap. The tree was planted as a bare root 2-3 years ago, at this time of year. I planted it so the root flare is exposed. I've fertilized with garrett juice and Azomite and compost. The sap started leaking about a year ago and got much worse this winter. You can see where the sap has been washed down to the ground by the rain. I'm in coastal Southern California. I have also used a fertilizer product called Blend sold by John and Bob, horticulturists out of Fresno California. Last year I got only 2-3 cherries, but it still is a young tree. (photos sent)
Do I need to worry about the leaking sap? Would a coat of "tree goop" help? — MH
Answer: You will need to apply the entire Sick Tree Treatment, starting with removing the soil from the root flare. That tree is far too deep in the ground. See the details under GUIDES on the homepage of dirtdoctor.com. I don’t know that product, it's probably OK.
Photos of Gummosis by Michael Huff
Here’s some info on gummosis from our site:
Gummosis is the oozing of sap from wounds or cankers on fruit trees. It can result from environmental stress, mechanical injury or disease and insect infestation. Cytospora canker or Valsa canker, the fungal cause of gummosis, affects stone fruit trees like apricot, cherry, peach, and plum. Gummosis caused by peach tree borers will be mixed with frass created by the insects.
Gummosis appears on fruit trees
Cytospora infection is distinguishable from insect damage and mechanical injuries because sawdust or pieces of bark are not mixed in the sap, as it would be with insect or mechanical damage. Cytospora canker is also known as perennial canker. The oozing sap from fungus, bacteria, physical damage (lawn mowers, weed eaters, hail, etc.) or environmental stress will be amber and opaque.
"Guttation" is a different condition where exudes water from structures called "hydathodes" on margins or tips of leaf blades. It is nature's way of allowing plants to relieve water pressure that can build up in their tissues under certain conditions. It is normally not a sign of stress in the plant.
The solution for any of these situations and resulting gummosis is to get the tree back into a healthy condition. The entire Sick Tree Treatment needs to be applied with the root flare being the most important step. Tree trunk Goop should be applied to any wounds or cankers.
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