Pepper mild mottle virus

Pepper mild mottle virus (PMMoV) is a highly contagious phytopathogen belonging to the Tobamovirus genus. It primarily targets pepper crops (Capsicum spp.), posing a significant threat to both greenhouse and field production worldwide. The virus is recognized for its high environmental stability, allowing it to persist in various substrates for extended durations.

Infected plants exhibit severe symptoms, including mosaic patterns on leaves, plant stunting, and significant fruit deformation. Fruits often appear bumpy, mottled, and undersized, rendering them commercially unmarketable. The impact on yield can be drastic, as the viral infection disrupts the plant's physiological processes, leading to reduced productivity and poor quality of the remaining produce.

The biology of PMMoV is characterized by its ease of mechanical transmission. It spreads efficiently during standard cultivation practices such as pruning, thinning, and harvesting. Furthermore, the virus is seed-borne, which allows it to be introduced into new growing areas easily. It also remains viable in the soil and on infected crop residues, serving as a primary inoculum source for subsequent seasons.

Environmental conditions, particularly in greenhouses, play a major role in the spread of PMMoV. High plant density and shared water sources or irrigation systems can accelerate the transmission process. Although temperature fluctuations affect symptom expression, the virus remains stable across a broad range of conditions, making total eradication in an infected environment extremely difficult.

Effective management strategy relies entirely on preventive measures, as there is no chemical cure for viral infections in plants. Key control practices include:

• Deployment of resistant or tolerant pepper varieties.
• Strict sanitation protocols for tools, machinery, and greenhouse facilities.
• Use of certified, virus-free seeds and transplants.
• Prompt roguing and destruction of symptomatic plants.
• Implementing rigorous hygiene standards for workers to prevent cross-contamination.