Oat necrotic mottle

Oat necrotic mottle virus (ONMV) is a significant plant pathogen belonging to the Potyviridae family, specifically within the Rymovirus genus. This virus primarily causes necrotic mottle and mosaic symptoms in various small-grain cereals, significantly impacting agricultural productivity.

The host range of the virus includes oats, barley, and wheat, as well as several wild grass species that serve as alternative hosts. The primary symptoms involve the development of necrotic streaks and mottled chlorosis on the leaves. Severe infections lead to stunted growth, reduced tillering, and inhibited grain development, which can result in substantial yield losses.

The biological cycle of ONMV is strictly linked to its vector, the eriophyid mite Abacarus hystrix. The virus is acquired by the mites during feeding on infected plants and is subsequently transmitted to healthy hosts. This transmission is non-persistent or semi-persistent, meaning the vector can spread the virus shortly after acquisition from a reservoir host.

Environmental factors play a crucial role in the dissemination of the virus. Mite movement is highly dependent on wind dispersal and ambient temperature conditions. In regions where perennial grasses are abundant near cereal fields, the incidence of the virus is significantly higher, as these grasses act as the main source of primary inoculum.

Management strategies for controlling Oat necrotic mottle focus on integrated pest management (IPM). Key practices include:

• Elimination of wild grass hosts adjacent to fields;
• Deployment of resistant or tolerant cereal cultivars;
• Targeted acaricide applications to control mite populations in early spring;
• Implementation of crop rotation to reduce the build-up of vectors.