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Phytophthera Root or Crown Rot - Phytophthora
spp.  
Edward L.
Barnard, Florida Dept. of Agriculture & consumer Sciences,
www.ipmimages.org
 HOSTS: Honeylocust, apple and crabapple, raspberry, stone fruits and junipers; other vegetable
crops, including asparagus. DESCRIPTION:
The most
obvious symptoms of root and crown rot are stunted, yellowing leaves,
premature fall coloration and leaf drop, and twig and branch dieback.
By the time the foliar symptoms develop, the rot canker may extend
halfway or more around the stem of the plant. In early stages, the
diseased bark is firm and intact while the inner bark is slimy and may
produce a moist, gummy exudate. Later, the affected area becomes
shrunken and cracked. LIFE
CYCLE: Phytophthera
fungal species overwinter as spores in soil or diseased plant material.
Species that cause root and crown rots enter host plants near the root
collar via wounds or the succulent parts of small roots. Fungal spores
move in water and are attracted to the root exudates from stressed
plants. CONTROLS:
Provide
good soil aeration, mulch woody species with 1-3 inches of composted
wood bark chips.In the case of vegetables, plant in raised beds to provide for good drainage. Keep the soil pH above 6.0. REMOVE AND DESTROY infected plants, including the roots. |
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