Hello Arnold,

It looks like the trees are suffering from something called Gummosis. I am pasting some information from Peach Diseases | Home & Garden Information Center (clemson.edu) here:

Gummosis

This disease can kill branches or trees and is caused by the fungus Botryosphaeria dothidea. The earliest symptoms appear on the young bark of vigorous trees as small blisters, usually occurring at lenticels. Infection occurs late in the season and may be apparent in the fall or the following spring. Some infected areas exude a gummy resin. Often, trees that are two or three years old have sunken diseased areas (cankers) apparent on the trunk and major branches. Large amounts of gummy exudate, or gumballs, are associated with lesions at multiple sites. After repeated infections, the bark becomes rough and scaly.

Prevention & Treatment: There is no practical chemical control available. Keep trees healthy since the most severely infected trees are water-stressed. Deadwood should be removed during winter pruning and destroyed. When pruning during the summer months, remove and destroy all pruned wood. Where gummosis is present, the use of captan or myclobutanil for scab control is the preferred treatment. See Table 1 for brands and specific fungicide products.

I am also attaching a PDF of a paper from the University of Florida Extension that is all about Gummosis. Bear in mind it is Florida-climate based advice, but I think it may still be informative.

Good luck!

Holly

Master Gardener Volunteer

CCE Ulster County