Armillaria Root Rot Of Oak

Disease Information

Armillaria Root Rot

 Symptoms and damage

This disease, caused by the fungus Armillariamellea, is widespread on oak. The symptoms are a slow decline of the tree. Mushroom fruiting structures on or near the root collar are prevalent in late summer and fall, especially during wet weather.


Remove diseased trees and as much of the root system as possible. Do not replant the site with a susceptible host. Trees which are resistant or tolerant to Armillaria root rot include baldcypress (Taxodiumdistichum), Chinese elm (Ulmusparvifolia), dawn redwood (Metasequoiaglyptostroboides), eucalyptus, ginkgo (Ginkgo biloba), Japanese cedar (Cryptomeria japonica), Leyland cypress (Cupressocyparisleylandii), maple (Acer spp.), sourwood (Oxydendrumarboreum) and sweetgum (Liquidambar styraciflua).


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