Hello Jonathan:

Thank you for contacting the UVM Master Gardener Helpline with your question about your peach tree.

I asked for assistance from the Director of the Plant Diagnostic Clinic and she provided the following advice:

“Lack of fruit was probably related to the late frost we had last year. In the #2438 picture (photo with flowers), I think I see orange fruiting bodies of the disease Nectria canker. This fungus typically comes in on winter-damaged tissue. (Crotch angles are more susceptible to winter damage and other issues.) https://hort.extension.wisc.edu/articles/nectria-canker/

Unfortunately, there is no cure for Nectria canker other than pruning out infected branches. Since this is in a crotch angle linked to the main trunk, you may want to leave it to see if the tree can live with it for several more years. Trees often have the ability to "wall off"
cankers and survive. Stone fruits often produce gummosis as a wound response. The wound could be from winter damage, a fungal disease or mechanical injury. If you notice any of this on branches, I would prune them out. Often it occurs on the main trunk so there is not much you can do.

There is no fungicide that is necessary at this point for the tree. I would be sure you are pruning on a regular basis and fertilizing the tree every spring. Watering during droughts is also helpful. Anything you can do to alleviate further stress in the tree will help it survive. Unfortunately, peaches are often not long lasting trees in Vermont. They go along fine for a while but tend to get winter-damaged at some point.

The other cracks in the bark are probably related to cold temperature injury. Many growers paint their peach trunks with a white latex paint to help with sunscald and some of these frost cracks. https://fruitgrowersnews.com/article/painting-tree-trunks-protects-against-rodents-borers/#:~:text=Painting%20fruit%20tree%20trunks%20with,followed%20by%20a%20daytime%20thawing.”

End of Ann’s response

I found a few articles about peach tree canker you will find useful:

Ohio State University Extension published a Fact Sheet which describes the canker and offers advice on controlling it which includes pruning out the impacted limbs. Make sure that you either burn or bag and remove the diseased limbs from the vicinity of your peach tree. In Vermont, it is ok to place diseased plants in the trash. https://ohioline.osu.edu/factsheet/plpath-fru-25.
"Winter injury, insect damage, and mechanical injury are common types of wounds serving as entry points." The “Control” section has specific steps you will want to follow.

Home Fruit Production: Peach and Nectarine Culture - University of Missouri Extension: https://extension.missouri.edu/publications/g6030

"Cankers often follow winter damage, sunscald or insect damage (Figure 4). After infection, the wounded tissue exudes large amounts of amber-colored gum. Later, the infected bark cracks open and the affected tissue turns black. Cankers should be removed by pruning; between cuts, disinfect pruning shears with an alcohol or bleach solution."

This article entitled “Peach Tree Pruning; Managing Light and Crop Load” published by
Pennsylvania State Extension will give you some guidance on how to properly prune your tree: https://extension.psu.edu/peach-tree-pruning-managing-light-and-crop-load

For additional information refer to “Proper Pruning Techniques” published by Earth-Kind Landscaping; Texas A&M Extension: https://aggie-horticulture.tamu.edu/earthkind/landscape/proper-pruning-techniques/

I hope this information is helpful. If you have any additional questions, please feel free to reach out. I hope your peach tree is able to overcome this canker and that you have a productive summer.