Mushroom Root Rot (fungus - Armillaria mellea): Mushroom root rot is caused by a soilborne fungus which attacks apples and causes a slow decline. Trees may be infected with the fungus for 2 to 3 years before death occurs. The vigor of the tree is noticeably reduced during this time. Trees infected with Armillaria mellea have a layer of creamy white fungal growth between the bark and the wood at the soil line. The growth (rhizomorphs) girdles the trunk and the tree dies when this girdling is complete. Trees damaged by the fungus can be diagnosed by the presence of the rhizomorphs and the advanced stage of decay of the root system. Infected trees are loose in the soil due to the deterioration of the root system.

Mushroom root rot is most often found in areas where post oaks were the predominate native timber and in sandy soils. This does not always hold true, and growers must be aware that the disease can cause serious losses in many soil types should it become established.

Soil fumigation will give only temporary control of this problem. The wide distribution of the fungus in the soil (both vertically and horizontally) and the constant recontamination of a fumigated area from nonfumigated soils reduce the early advantage gained by soil fumigation. Resistant root stocks are not available. Growers should avoid planting in areas where the fungus has been a problem in the past or on recently cleared post oak timberland.

It is best for a homeowner to move to another planting site should plants die from mushroom root rot.

See section on Mushroom Root Rot

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