By Emmanuel Byamukama
Brome Mosaic Disease
Brome mosaic disease was found in one corn field in Brookings County with just a few plants in the head-rows showing infection. Infected plants were stunted and had chlorotic streaks parallel to the veins (Figure 1). Some of the plants also had systemic (throughout the plant) necrotic lesions (Figure 2).
Figure 1. Brome mosaic symptoms on corn. Notice the chlorotic streaks running parallel to the veins and stunted corn plant (bottom picture)
Brome mosaic disease is caused by Brome mosaic virus. This virus is thought to be transmitted by nematodes (Longidorous and Ximphinema). The disease is considered minor in corn because of the low numbers of plants which get infected in a field partly due to the slow movement of the vector in the soil. Infected plants are usually found in the rows close to the grass borders. Several grasses are also hosts for Brome mosaic virus.
Figure 2. Stunted corn with necrotic lesions due to Brome mosaic virus.