- Lettuce big-vein disease
Lettuce big-vein disease causes leaf distortion and ruffling in affected
lettuce plants.This disease was first associated in 1983 with a rod-shaped
virus "Lettuce big-vein associated virus", which is transmitted by the obligatelyparasit ic soil-inhabitingfungus , "Olpidium brassicae ". However, in 2000 a second virus "Mirafiori lettuce virus " was found in lettuce showing big-vein symptoms. Furthermore, since the lettuce infected with this virus alone developed big-vein symptoms, it is considered to be a main agent of the big-vein disease.
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