Pea Enation Mosaic Virus Detected in Divide County

Be on the lookout for Pea Enation Mosaic virus (PEMV). A pea plant exhibiting interveinal chlorosis was found by a crop scout in a field in southern Divide County (Fig 1). Genetic based lab testing by the MSU Regional Pulse Crop Diagnostic Laboratory found that the plant was infected with PEMV. PEMV is a viral disease that can infect many legumes including pea, chickpea, faba bean and lentil and is transmitted by pea aphid and green peach aphid, in addition to several other aphid species. Symptoms can vary based on host and environment, but infected plants will typically develop yellow or translucent flecks on the leaf (Fig 2A), vein clearing and later on “enations” or leaf blisters may appear (Fig 2B). Leaves might also be twisted or edges may have a downward roll. These early symptoms can easily be confused with herbicide damage, nutrient deficiency or other viruses, so laboratory diagnoses is important. PEMV may also cause stunting and a reduction in internode length. Pods may be twisted, deformed or develop a “warty” appearance (Fig 2C). If the plant is infected prior to bloom, pods may not fill normally and yield may be impacted.

Few management options exist for PEMV. Reducing aphid populations with an insecticide application may reduce the secondary spread of the virus. However, it is unclear if that application would be cost-effective. In planning for next year resistance could be an option. Hampton, a PEMV resistant green field pea variety was released, and although it was developed for conditions in the Pacific Northwest, it may be a good option for growers who have problems with this disease.