Virus diseases

Peas are susceptible to a large number of aphid- transmitted viruses, which can produce diseases individually or in combination. The main viruses infecting pea are pea enation mosaic, pea streak and bean yellow mosaic.

1) Pea enation mosaic virus (PEMV)

In addition to pea, PEMV also infects broad bean, sweet pea, and alfalfa. It probably overseasons in many common perennial legumes. The virus is spread in nature most efficiently by the pea aphid (Acyrthosiphon pisum) and to a lesser extent by the green peach aphid (Myzus persicae). The virus is transmitted in a persistent (circulative) manner. Infected pea plants develop mosaic and chlorotic vein flecking (appears as translucent windows) and veinal enations (blisterlike outgrowths), which are very characteristic for pea enation mosaic virus. Plants are stunted, and proliferation of basal branches is common. Pods are distorted, split open, and may show prominent enations.

2) Bean yellow mosaic virus (BYMV)

Bean yellow mosaic virus is transmitted by at least 20 aphid species in a non-persistent manner. The symptoms depend upon the strain of virus involved. The pea strain, for example, causes a very bright yellow mosaic whereas the more typical isolates produce a dull light and dark green mosaic. Symptoms are masked or delayed at low temperatures (below 15 °C ), but develop at 18 - 23°C . Seed transmission is absent or very rare in pea and several other legumes.