Identifying and Treating Turnip Diseases
The turnip is a vegetable that grows from the late summer and early autumn. It needs little care and tends to flourish as the colder weather sets in and rainfall increases.
Despite its easy-to-grow nature, the turnip, like most root plants, is vulnerable to a number of diseases, including fungal and bacterial infections, mineral deficiency and rot.
Common Turnip Diseases
One of the most common diseases in the turnip family is white or leaf spot. This disease causes gray or white spots to form on the leaf. The spots eventually increase to cover the whole leaf and make the greens and the root unsuitable for harvesting.
Another form of fungus, downy mildew, appears as a white, fuzzy patch on the underside of turnip leaves. It may also damage the roots.
The turnip family is very vulnerable to clubroot, which causes galls to form on the roots. It will yellow above-ground leaves and stems. This fungus can live in the soil for seven or more yeas after the initial infection.
Rhizoctonia rot causes elliptical lesions, with a scabby appearance, on the stem and body of the turnip. This rot is sometimes linked to the root maggot, so eliminating that pest should help to reduce rot problems.
Blackleg can cause dark cankers in the flesh of the turnip, or may also be found as rot on stored vegetables. Stems may sustain demage where they contact the soil. Blackleg can even completely destroy the root system.
Treating Turnip Diseases
For diseases such as white spot or downy mildew, spraying fungicides might be the best option. Use products early in the season and continue until you harvest the turnips. Copper-based fungicides are widely available at garden centers and supply stores, and these help to keep leaf spot and white spot away from plants. When using fungicide, remember that most of these mixes also contain insecticides. Check labels carefully.
For clubroot, you should avoid planting any vegetables of the turnip family in the infected soil. Burn roots, plants and weeds from the infected area. Use resistant strains of turnips in the surrounding area.
For rot, combat maggots and avoid storing turnips above 39 degrees F.
For blackleg, practice rotation. Also destroy weeds and roots from the surrounding soil. Avoid moving the soil in this area while it's wet, and be sure to clean all tools used in digging the infected soil.
Preventing Turnip Diseases
The best ways to avoid disease are using good gardening practices and rotating crops. Always wash your equipment with bleach between uses, and wash your hands thoroughly to prevent the spread of disease. Crop rotation can help keep mold and fungus from spreading between crops; viruses in particular can live for a number of years in the soil and in weeds, so keep areas previously used for growing turnips fallow and free of weeds.