Causal Agent
Tobacco etch virus (TEV)
Vector
Aphids (Myzus persicae and others)
Distribution
North and South America
Symptoms
Disease symptoms have been reported on tomato that range from a mild mottling and slight distortion of the foliage to a severe mottling and crinkling of the foliage. Fruit are often reduced in size, mottled and misshapen. Usually, the earlier the plant is infected, the greater the effects on plant stunting and yield.
TEV: mottled fruit. (Courtesy of Tom Zitter, Cornell University)
Conditions for Development
Many species of weeds can act as a host for the virus, and it can be transmitted by at least 10 species of aphids. TEV is transmitted in a non-persistent manner by virus carrying aphids moving into tomato fields from nearby solanaceous weeds, peppers and other tomato fields that are already infected. Secondary infection may be caused by aphids, or the virus may be mechanically transmitted through staking, pruning or handling of infected plants.
Control
Removing weed hosts that may harbor the virus is important. Avoid locating tomato productions near pepper crops because peppers can be a major source of the virus. Reducing the spread of the disease by controlling the aphid vector population is very difficult and generally not practical.