Alternanthera mosaic virus

Alternanthera mosaic virus (AltMV), belonging to the Potexvirus genus, is a significant plant pathogen characterized by flexible, filamentous virions. This virus causes systemic infections in various botanical hosts. It is highly contagious, particularly in environments where plants are frequently handled or pruned, making it a persistent issue in nurseries.

The virus primarily affects ornamental plants, with Alternanthera species being the most common hosts. However, it also poses a risk to various legumes and solanaceous crops. The virus interferes with the host's normal biological functions, leading to significant physiological stress and reduced aesthetic or economic value of the infected plants.

Symptoms of AltMV infection vary depending on the host species but commonly include mosaic patterns, chlorotic spotting, leaf crinkling, and stunting. In advanced stages, severe leaf deformation and systemic necrosis can occur. Because symptoms are often mild initially, infected plants can serve as silent reservoirs for the virus within a greenhouse collection.

Transmission occurs primarily through mechanical means. Contact between healthy and infected tissues, contaminated pruning tools, or even contaminated soil and water can spread the virus. AltMV is known for its remarkable stability on surfaces, allowing it to remain infectious on tools, clothing, and greenhouse benches for extended periods.

Prevention is the only effective management strategy for this viral disease. Since there are no antiviral pesticides available for plant treatment, strict sanitation practices must be implemented:

• Sanitize all cutting tools with a 10% bleach solution or commercial disinfectants between uses;
• Source plant material only from certified virus-free nurseries;
• Immediately rogue and destroy infected plants;
• Maintain a strict quarantine policy for new plants entering your facility.