Pearl millet mosaic virus

Pathogen and disease type. Pearl millet mosaic virus (Potyvirus penniseti) is a member of the genus Potyvirus within the Potyviridae family. It is an RNA-based plant virus that causes systemic infection in various cereal crops. As an obligate parasite, it relies entirely on the host plant's cellular machinery to replicate, which severely disrupts the plant's metabolic pathways.

Susceptible crops. The virus primarily affects species within the Poaceae family. The most economically significant hosts are pearl millet (Pennisetum glaucum) and broomcorn millet (Panicum miliaceum). A wide range of wild grasses can also host the virus, serving as a primary source of inoculum during the inter-cropping seasons.

Symptoms and signs of infection. The characteristic symptoms include distinct mosaic patterns on leaves, appearing as alternating light and dark green patches, streaks, or chlorotic stripes. In severe cases, infected plants exhibit stunted growth, leaf deformation, reduced tillering, and poor spike development, which significantly impacts the overall grain yield and quality.

Conditions for development and severity. The virus is primarily transmitted through aphids, which act as persistent vectors. The disease spreads most rapidly during warm, dry periods when aphid populations are at their peak. The economic impact is substantial, leading to stunted plants, decreased grain filling, and reduced germination rates of seeds produced by infected plants.

Protection and prevention measures. Since there are no chemical cures for viral infections in plants, management focuses on preventing the spread:

• rigorous weed control to remove alternate hosts;
• application of systemic insecticides to manage aphid vector populations;
• using certified disease-free seeds;
• implementing proper crop rotation and isolation distances to prevent infection from neighboring fields.