Brown Rot
(fungus - Monilinia fructicola): The brown rot fungus causes blossom blight
and fruit rot, but fruit rot is the most common. Surface moisture and moderately
warm temperatures favor disease development. With blossom blight, flowers turn
brown and are water-soaked. The fungus grows down the pedicel into the stem resulting
in dark brown, sunken areas. Young stems are
often girdled causing twig dieback. In some instances, young fruit may become
infected but not show symptoms until the fruit matures. Generally, fruit are resistant
to infection during the hard green stages of development. Fruit are most susceptible
near maturity. The fungus enters fruit directly or through natural openings or
wounds. A brown, water-soaked lesion rapidly develops. The brown rot fungus overwinters
in mummies, stem cankers and on infected fruit peduncles. Beetles or other insects
can be vectors for the fungus. Control by applying a fungicide
during pink bud, bloom, petal fall, and at preharvest. Post harvest decay can
be serious if fruit is not protected. Nectarines are more susceptible than peaches.
