Information on white turnip greens: What causes white spots on turnip greens?
Turnip leaves are a special treat, whether eaten raw or cooked. Their leaves are rich in vitamins A, C and K, as well as many other minerals and nutrients. Their health benefits are many and the leaves are easy to grow and harvest. However, it is not uncommon to find white spots on turnip leaves. White spot on turnips causes economic damage where turnips are grown only for their green leaves. Learn how to prevent white turnip spots and save these healthy greens.
Recognition of the white spot on turnip
Vegetables of all kinds offer many nutritional benefits. Turnip greens can be considered a southern delicacy, but even gardeners in the North can grow and harvest these delicious leaves. Whether you cook them in the broth of a pork shank, eat them raw in a mixed salad or sauté them in vegetable oil, turnip greens have a powerful vitamin and mineral effect. A turnip with white spots on the leaves can be a sign of a highly infectious disease. Early detection is essential because seedlings can die on the spot if infected when young.
Lesions are visible on young or old leaves. They are grey to brown in colour despite
the name of the disease. The edges of the lesion darken as it matures, while the centre of the spot becomes pale and almost white. Leaves quickly turn yellow, die and fall off. Blotches form on the cotyledons, stems and petioles.
Although a few infected leaves are not a problem, the disease spreads rapidly under optimal conditions. If plants lose too many leaves, the root cannot develop and essential carbohydrates are not harvested by photosynthesis. This hinders the plant’s ability to produce more leaves and ultimately results in poor health and fewer vegetables to harvest.
Causes of white turnip spot
A turnip with white spots is the result of a fungus called Cercosporella brassicae . The disease can affect many plants of the Brassica group, such as mustard and cabbage, and is most common when daytime temperatures are between 55 and 65 degrees Fahrenheit (13 to 18 C.). High humidity is also a causal factor.
The disease is spread by wind and rain, but can also be present in seeds or in Brassica waste and wild host plants in winter. Plants that are too crowded and poorly ventilated are also more prone to a high incidence of the disease. Aerial watering during periods when leaves do not have time to dry overnight can also improve fungal spore development.
Management of white spots on turnip leaves
The best control is to avoid white spots on turnip leaves from the start. Grow turnip leaves only once every 3 years in the same spot. If possible, use certified disease-free seed and do not harvest seed from infected plants.
Keep weeds, especially Brassica weeds, away from existing crops. Monitor the crop and immediately remove any infected plant material to prevent the spread of the fungus. Clean up crop debris and discard it if any of the plants show signs of disease.
Copper hydroxide has been shown to be effective in preventing disease if applied early in seedling development. Apply fungicides weekly as a foliar spray when conditions are favourable for disease development. If possible, spray under leaves to keep them dry and prevent fungal spores from spreading under perfect conditions.
