Sorghum mosaic

Systematic position and nature of the pathogen
Sorghum mosaic is caused by the Sorghum mosaic virus (SrMV). It belongs to the Potyviridae family and the Potyvirus genus. As a plant pathogen, it contains single-stranded RNA and systematically infects host plants, leading to severe physiological disruptions that affect growth, development, and overall yield potential.

Diseases and host crops
The virus is primarily known for causing mosaic disease in sorghum species, including grain, forage, and sweet sorghum. Other susceptible hosts include corn (maize) and various wild grasses. The infection manifests as visible mottling or mosaic patterns on the leaves, which significantly interferes with the plant's photosynthetic capacity.

Biology and life cycle
The life cycle of the virus is closely tied to its insect vectors, particularly aphids. Transmission is non-persistent; the virus attaches to the aphid's mouthparts when it feeds on an infected plant and is transmitted to a healthy plant within a very short timeframe. This efficient vector transmission allows the virus to spread rapidly across fields during the growing season.

Environmental conditions and damage
The spread of SrMV is favored by climatic conditions that support high aphid populations. The virus survives in perennial grass weeds during the off-season. Economic damage is substantial, as infected plants exhibit stunted growth, reduced leaf area, and lower grain yield. In sweet sorghum, the virus significantly reduces the accumulation of sugars in the stalks.

Control and protection measures
Management of Sorghum mosaic involves several integrated approaches:

• Planting resistant or tolerant cultivars is the most effective long-term strategy.
• Controlling aphid populations with appropriate insecticides at the onset of colonization.
• Rigorous weed management, especially targeting perennial grasses that serve as winter reservoirs.
• Using certified clean seeds to prevent initial pathogen introduction.
• Implementing field separation and isolation strategies to minimize the influx of virus-carrying aphids from nearby infected crops.