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Apple mosaic virus

Apple mosaic virus (ApMV)

Young leaves develop pale to bright cream-colored spots, blotches, bandings or patterns as they expand in the spring (A). These turn brown and become necrotic as they age and premature defoliation may occur when infection is severe. Symptom expression is highly variable among varieties.

Distribution

Common to all fruit-growing regions in eastern North America.

Similar Species

None

Management

The virus is exclusively mechanically transmitted; i.e., there are no known insect vectors. Therefore, ApMV can be avoided by planting trees that are certified virus-free. Transmission can occur in the orchard through root grafts; roguing infected trees will limit the spread. Almost all varieties are susceptible to the virus, but some express symptoms more readily than others. Golden Delicious, Granny Smith and Jonathan are very susceptible; McIntosh is moderately susceptible. Infected trees may still produce a good crop.

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