Panicum streak virus

Pathogen and disease type. The disease is caused by Mastrevirus ciliaris, a virus belonging to the Mastrevirus genus within the Geminiviridae family. It is an obligate viral pathogen that interferes with the plant's vascular system. As a viral infection, it relies entirely on specific insect vectors for transmission and persistence within agricultural ecosystems.

Host range. The pathogen primarily affects plants within the Poaceae family. Millet (Panicum miliaceum) is the most significant crop host, though the virus can also colonize various wild grasses. These wild reservoirs are crucial for the virus's survival during the off-season, acting as a bridge for reinfection of subsequent crop cycles.

Symptoms and signs. Clinical signs of the infection typically manifest as chlorotic streaks or stripes running parallel to the leaf veins. Affected plants exhibit severe stunting, leaf deformation, and reduced vigor. In advanced stages, the plants fail to develop normal inflorescences, leading to significant yield losses and poor grain filling.

Development and spread. The virus is transmitted by leafhoppers. The epidemiology of the disease is closely linked to the population dynamics of these insect vectors. Environmental conditions that favor the proliferation of leafhoppers—such as warm, dry weather—lead to increased rates of viral transmission, as the insects move from infected reservoir hosts to healthy crop plants.

• Planting resistant or tolerant cultivars and hybrids.
• Effective management and removal of weed reservoirs.
• Application of insecticides to control leafhopper populations.
• Maintaining field isolation to prevent vector migration.
• Adhering to recommended planting dates to avoid peak insect activity.

Economic impact. Mastrevirus ciliaris poses a serious threat to cereal production. The infection disrupts physiological processes such as photosynthesis, resulting in stunted growth and significantly reduced grain quality. Severe outbreaks can lead to major economic losses, necessitating rigorous integrated pest management strategies to protect the harvest and ensure agricultural productivity.