Cabbage is one of South Africa’s most important vegetables, supplying mostly fresh markets. Cabbage producers now face an increasingly challenging viral disease: Brassica stunting disorder, caused by the Turnip yellows virus (TuYV).  This disease, though not always obvious at first glance, can significantly reduce yields and quality.

 What is TuYV?

Turnip yellows virus is mainly transmitted by the green peach aphid (Myzus persicae). Once infected, an aphid carries the virus for life, spreading it rapidly between plants. Because TuYV is a viral disease, it cannot be “cured” with sprays, making prevention and management critical.

Symptoms in Cabbage

In South African cabbage fields, TuYV infection results in:

• Stunted plants with reduced head size
• Purpling or yellowing of older leaves, often mistaken for nutrient deficiencies
• Poor head formation, reducing marketability
• Delayed maturity, leading to uneven harvesting
• Browning (necrosis) of vascular bundles, causing poor translocation of nutrients and water

Early symptoms are subtle, meaning that cabbage producers only recognise the disorder once yields and quality losses are already severe.

Impact on Local Production

There have been reports of reduced marketable yields linked to stunting disorder across South Africa. International studies show that TuYV can reduce brassica yields and local trends indicate that South African cabbage producers are at higher risk. For smallholder producers, the effect is especially harsh – fewer and smaller heads mean reduced income and less food supply.

Management Strategies

Since there is no cure for TuYV, integrated pest and crop management is the best defense:

• Early aphid monitoring and control through scouting and threshold-based sprays
• Crop hygiene: removing brassica weeds and volunteer plants that act as virus hosts

The Way Forward

With changing weather patterns and especially the last mild winter not having the usual intense cold periods, favouring aphid activity, awareness of TuYV in cabbage production is essential.  Extension support, accurate diagnosis and coordinated management practices will help protect South Africa’s cabbage producers from this hidden but serious disease threat.

 DISCLAIMER:  This information is based on our observations and/or information from other sources. As crop performance depends on the interaction between the genetic potential of the seed, its physiological characteristics, and the environment, including management, we give no warranty express or implied, for the performance of crops relative to the information given nor do we accept any liability for any loss, direct or consequential, that may arise from whatsoever cause. Please read the Sakata Seed Southern Africa (Pty) Ltd Conditions of Sale before ordering seed.