Sorghum mosaic virus

The virus primarily affects monocotyledonous plants, particularly those in the Poaceae family. Sorghum is the main host, though it can also infect other cereal crops and wild grasses under favorable conditions.

Transmission occurs mainly through mechanical means, such as contact between infected and healthy plants, and via insect vectors. Aphids are the most common vectors responsible for spreading the virus throughout fields.

The virus survives the winter period in the root systems and debris of perennial grassy weeds, which serve as the primary source of infection at the beginning of the growing season.

Seed transmission is generally not considered the primary route for this virus, but surface contamination of seeds can occur in heavily infested areas, contributing to localized outbreaks.

The most distinctive symptom is the development of a mosaic pattern on young leaves, appearing as alternating light green, yellow, or chlorotic patches and streaks.

As the disease progresses, leaves may become deformed, curled, or stunted. Infected plants typically exhibit shortened internodes, which gives them a visibly dwarfed or stunted appearance.

Severe infections may lead to necrosis in leaf tissues, manifesting as thin stripes or rings, which indicate significant metabolic disruption within the plant cells.

Reproductive development is frequently impaired; infected plants show delayed flowering, and the panicles produced are often malformed, sterile, or produce shriveled, low-quality grains.

Symptom severity is highly variable and depends on the plant's growth stage at the time of infection, as well as environmental stresses like high temperature or moisture deficiency.

Sorghum mosaic virus poses a significant economic threat, as it substantially reduces biomass and grain yield. Early-season infections can result in severe crop losses.

The virus interferes with photosynthetic activity, reducing the plant's ability to synthesize essential nutrients, which leads to poor development of both vegetative and reproductive organs.

Marketable quality is severely compromised; the grains produced by infected plants are often underweight, possess poor germination energy, and are unsuitable for high-quality food or feed production.

Infected crops show increased vulnerability to abiotic stresses, such as drought or heat waves, which are common in sorghum-growing regions and exacerbate the impact of the viral infection.

Weakened plant immunity caused by the virus makes the crops more susceptible to secondary infections by pathogenic fungi and bacteria, leading to a synergistic decline in field health.

The use of resistant or tolerant cultivars is the most effective long-term strategy for managing Sorghum mosaic virus and minimizing potential economic losses.

Strict sanitation practices, particularly the elimination of perennial weeds that serve as virus reservoirs in and around the field edges, are essential for effective prevention.

Integrated pest management (IPM) focusing on controlling aphid populations through timely insecticide applications can help limit the spread of the virus during critical growth stages.

Crop rotation and maintaining a spatial buffer between newly planted fields and fields with a history of infection can effectively reduce the risk of primary viral transmission.

• Regular field scouting to identify and remove symptomatic plants early.
• Optimizing planting dates to avoid peak periods of insect vector activity.
• Post-harvest destruction of crop residues to reduce overwintering sites.
• Application of balanced fertilizers to support vigorous plant growth and stress tolerance.