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Apple
Disease
Anthracnose and Bull's-eye rot
Bitter pit
Burrknot
Crown and collar rot
Crown gall
Cytospora canker
Fire blight
Fruit russeting
Nectria canker (European canker)
Nectria twig blight (Coral spot)
Perennial canker (Bull's-eye rot)
Phytophthora fruit rot
Powdery mildew
Scab
Virus diseases
Insect
Aphids
Apple ermine moth
Apple maggot
Apple-and-thorn skeletonizer
Brown marmorated stink bug
Codling moth
Cutworms and armyworms
Earwigs
Fruittree leafroller
Leafhoppers
Leafrollers
Lecanium scale
San Jose scale
Spider mites
Tent caterpillars
Tentiform leafminer
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Caption: Apple crown and collar rot
Photo by: J.W. Pscheidt
Apple : Crown and collar rot
(revision date: 5/20/2014)
Use Integrated Pest Management (IPM) for successful plant problem management.
Biology
Crown rot of the rootstock and collar rot of the scion wood of apple trees is caused by a soilborne fungus. It can survive in infected tissues and plant debris, as well as in the soil. Symptoms typically appear in early fall, when one or more branches show signs of decline, including discolored (reddish-bronze to purple) foliage, smaller leaves and terminal growth, and a red discoloration of the bark. Infection occurs in the roots and moves within the roots to the crown. The bark is killed, and the cambium beneath the bark turns reddish-brown, instead of the normal white color. Crown or collar rots may completely girdle trees, resulting in death.
Management Options
Non-Chemical Management
Plant disease-resistant cultivars such as 'Antonovka', 'Delicious', and 'Wealthy'. 'Golden Delicious', 'McIntosh', and 'Rome Beauty' are moderately resistant.
The rootstocks M9 (highly resistant) and M2, M7, M26, and MM111 (moderately resistant) resist crown and collar rot.
Do not overwater or allow water to pool at base of trees.
Avoid wounding crowns and collars.
Cut out diseased tissues from crowns in dry weather and leave wounds exposed to the air.
Select non-chemical management options as your first choice!
Chemical Management
IMPORTANT:
Visit Home and Garden Fact Sheets for more information on using pesticides
None recommended
Images
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Caption: Apple crown and collar rot
Photo by: J.W. Pscheidt