Answer: Members of the Prunus family (peach, pear, apricot, cherry) are subject to gummosis. The gumming is a result of mechanical injury, insect damage, fungal diseases, or improper growing conditions. Sometimes it happens because too much water or nitrogen fertilizer have been applied.
You should inspect to see that there are no cankers on the trunks of the trees that might be harboring disease spores. Check to see that there is no insect activity. Once you've ruled out those two problems, then withhold fertilizer and water thoroughly only about once a week so you don't encourage fast but weak growth. You can protect the trees with a fungicide before new spring growth begins.
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