Turnip mosaic virus

Turnip mosaic virus (TuMV) is one of the most widespread and economically devastating viral diseases affecting brassica crops globally. Although formerly associated with the Tymovirus group, it is now identified as a member of the Potyvirus genus, causing systemic infection that results in severe physiological stress and stunted development of host plants.

The host range is broad, significantly affecting vegetable crops such as all cabbage varieties, broccoli, kale, turnips, radishes, and rapeseed. Additionally, many common cruciferous weeds serve as vital overwintering hosts, allowing the virus to persist in the environment and infect new plantings during the spring season.

Symptoms typically present as distinct mosaic patterns, chlorotic rings, leaf curling, and severe distortion of the foliage. In heavily infested crops, the plant may stop growing entirely, with reduced head formation in cabbage or deformed, non-marketable roots in root vegetables, leading to significant yield losses in commercial production.

The virus is primarily transmitted by various aphid species in a non-persistent manner, meaning the insect can acquire and transmit the virus within seconds of feeding. Furthermore, mechanical transmission occurs through contaminated hands, machinery, or tools, especially when pruning or harvesting, making field hygiene a critical aspect of farm management.

Integrated management is essential for controlling this virus, as chemical treatments directly targeting the virus are unavailable. Recommended strategies include:

• Strict weed control to eliminate alternative hosts around the field.
• Systematic monitoring and control of aphid populations using registered insecticides.
• Utilizing certified disease-free seeds and planting resistant or tolerant cultivars.
• Implementing temporal and spatial isolation between successive plantings of brassicas.
• Disinfecting all agricultural tools and equipment to prevent mechanical spread between plants.