Agriculture Reference
In-Depth Information
Commercial growers who have bitter pit problems in their orchards may
choose to delay harvesting as long as possible, refrigerate the fruit, and delay
packing for at least 4 weeks. By that time, surface symptoms will be visible,
and affected fruits can be removed from the packing line.
Stone Fruit Diseases
Cherries, peaches, plums, and other stone fruits are often called soft fruits.
They typically ripen earlier in the season than most pome fruits and have
short shelf lives. Stone fruits can be challenging to grow organically in humid
areas due to brown blight and other diseases.
Brown Blight
Also called brown rot, blossom blight, and fruit rot, brown blight is wide-
spread and among the most serious diseases of stone fruits. The disease at-
tacks the flowers, fruits, twigs, and branches of many different crops, includ-
ing apricots, cherries, nectarines, peaches, and plums. High humidity greatly
increases brown blight problems, and the disease is especially common and
severe in eastern North America.
Causes.
Two different fungi,
Monilinia fructicola
and
Monilinia laxa
, cause
this disease or complex of diseases. The pathogens survive on infected twigs
and branches and in mummified flowers and fruits on the trees or on the
ground. Air currents and splashing water spread the spores, which are re-
leased at temperatures above 40°F (4°C). Infections can occur at any above-
freezing temperature when the trees remain wet for 24 hours or more. Fol-
lowing initial infection, secondary infections develop during the remainder of
the season from spores that form on infected twigs, blossoms, and fruits.
Symptoms.
Flowers can become infected at any time, but they appear to be
most susceptible at full bloom. The flowers may become water-soaked and
look as if they have been damaged by frost. They may also mummify and
