We have a mature ornamental cherry or plum tree that suffered
\nfrom brown rot last year. We removed all affected branches and leaves. We were told that we might need to do something else this winter or spring–spray the tree with something, possibly. Can you advise us on how to keep our tree healthy?<\/p>\n
<\/p>\n
I consulted The Organic Gardener’s Handbook of Natural Insect and Disease I found sources for less toxic (but still not hazard-free) versions of
\nControl<\/em> edited by Barbara Ellis (Rodale Press, 1996), and this resource
\nrecommends doing what you already did, by removing and destroying
\naffected parts of the tree. At the beginning of the growing season (early
\nspring) you can spray sulfur to control this fungal disease on blossoms.
\nIf you were growing fruit, you would spray again later in the season to
\nprotect the fruit, but since this is an ornamental tree, it isn’t
\nnecessary. Copper sprays are also used to control the disease. Washington
\nState University Extension recommends preventive measures, such as
\navoiding wounding trees (damaging bark with string
\ntrimmers\/weed-whackers\/lawnmowers, or making bad pruning cuts). Avoid
\nwetting the blossoms and leaves, and keep the tree pruned for good air
\ncirculation in the canopy. Avoid excessive nitrogen fertilizer. While the
\ntree is in bloom, check it frequently for symptoms, and destroy any
\ndiseased parts as soon as you notice them.<\/p>\n
\nthese fungicides from Peaceful Valley Farm & Garden Supply<\/a>, but they may
\nbe available at your local garden center as well. Some of these require a
\npesticide handler’s license.<\/p>\n