Pea enation mosaic virus

The causal agent of this disease is the Pea enation mosaic virus (PEMV), classified within the genus Enamovirus. It is a persistent, aphid-transmitted plant virus that causes systemic infections in various host plants. The virus particle consists of a bipartite single-stranded RNA genome enclosed in a protein capsid, making it highly adapted to its vectors.

The virus primarily affects plants in the Fabaceae family. Key susceptible crops include peas, fava beans, lentils, and certain clovers. Wild legumes often act as reservoir hosts, maintaining the virus in the environment between growing seasons and serving as the primary source of inoculum when new crops are sown.

Disease symptoms are highly distinctive, often starting as chlorotic spots and streaks on younger leaves. The hallmark of the infection is the development of enations, which are hyperplastic tissue outgrowths occurring mainly on the undersides of leaves and stipules. Severely infected plants typically exhibit stunting, leaf curling, and significant distortion of pods, leading to poor seed set.

Transmission is exclusively biological, mediated by various species of aphids, such as the pea aphid (Acyrthosiphon pisum). The virus has a persistent-circulative mode of transmission, meaning the aphid must feed on an infected plant for a certain period to acquire the virus before it can transmit it to healthy tissue. Environmental conditions favoring rapid aphid population growth are critical drivers of disease outbreaks.

Effective disease management relies on an integrated pest management (IPM) approach. Strategies include selecting virus-resistant cultivars, which is the most sustainable solution. Additionally, farmers should prioritize the control of aphid populations using targeted insecticides, maintaining spatial isolation from perennial legume crops, and practicing rigorous weed management to remove asymptomatic reservoir hosts from field borders.