Alfalfa Mosaic Virus

Causal Agent

Alfalfa mosaic virus is a single-stranded RNA virus transmitted by several aphid species through feeding. 

Symptoms

Infected plants display white-yellow blotches in a mosaic pattern on the foliage. Pepper fruits may have white discoloration that occurs in ring spots. Younger plants become stunted and may produce none to small, deformed fruit. Tomatoes with preexisting fruits often exhibit necrotic spots or blotches. Some plants may be asymptomatic.

Disease Cycle

AMV spreads by aphids feeding on plant tissues with their piercing-sucking mouthparts. The virus is only transferable a short time after its acquisition, but aphids can re-acquire the virus anytime they feed on infected plants.

Management

Chemical control is ineffective, as viral spread occurs too quickly through aphid populations. If possible, avoid planting susceptible crops near alfalfa fields.