Cherries, apricots, and a few related species are particularly susceptible to fungal and bacterial canker diseases, including Eutypa dieback, Botryosphaeria canker, and bacterial canker. Pathogens can be spread by rain or tree wounds – such as pruning wounds – during wet weather; subsequent infections spread through the wood for several years and may eventually kill the tree.
Late summer is the best time to do final pruning, but with precautions to prevent the tree from sunburn.
To learn more, see the article “Avoid Pruning Apricots and Cherries in the Cool Season” from the November 2014 issue of the UC IPM Retail Nursery and Garden Center IPM News.
Find out about common pests of cherries and apricots on the UC IPM web site and learn more about caring for cherry and apricot trees on the UC California Backyard Orchard web site.