Common Disease Problems
Anthracnose: This is a fungus disease causes circular or irregularly shaped dry spots grey to straw color on the leaves. The lesions may coalesce and form dead tissue that turns yellow, or they may split or crack in the center. The fungus overwinters in diseased plant debris. Burpee Recommends: Provide sufficient space between plants for good air circulation, avoid overhead watering which can spread the fungus spores, keep a clean garden, remove and discard all diseased plant material and rotate crops.
Cercospora Leaf Blight: Small flecks which develop a yellowish halo appear on the leaves and turn brown and coalesce. They cause the leaves to wither and die. Burpee Recommends: Remove infected plants and destroy all plant debris. Rotate crops.
Clubroot: Leaf symptoms include stunting, yellowing and wilt. When the plants are removed from the soil the roots may have galls, swelling and distortion. Burpee Recommends: Test the soil pH. Clubroot is most common in acid soil, add lime to raise the pH. Avoid planting where Brassica plants were grown the previous year.
Downy Mildew: This fungus causes whitish gray patches on the undersides and eventually both sides of the leaves. Burpee Recommends: Rotate crops with plants in a different family. Avoid overhead watering. Provide adequate air circulation, do not overcrowd plants. Do not work around plants when they are wet.
Turnip Mosaic Virus: This virus causes yellow and green mosaic patterns on leaves and dead areas, yellowing may occur on older leaves. It causes black spots and brown necrotic streaks on stems. Overall growth is stunted and yields are reduced. Burpee Recommends: This disease is spread by aphids so control aphids. Remove and destroy infected plants.
Common Pest and Cultural Problems
Aphids: Greenish, red, black or peach colored sucking insects can spread disease as they feed on the undersides of leaves. They leave a sticky residue on foliage that attracts ants. Burpee Recommends: Introduce or attract natural predators into your garden such as lady beetles and wasps which feed on aphids. You can also wash them off with a strong spray, or use an insecticidal soap.
Cutworms: These insects cut off the seedlings at the soil level. Burpee Recommends: Place a paper cup collar (use a coffee cup with the bottom cut out) around the base of the plant. They are usually mostly a problem with young seedlings. You can also control by handpicking and controlling weeds, where they lay their eggs.
Flea Beetles: These small hopping beetles feed on plant foliage and may spread diseases. Burpee Recommends: Rotate crops with plants in a different plant family. Use floating row covers to prevent damage to young foliage.
Root Maggots: Leaves wilt and growth is stunted. These maggots are white and feed on the roots. They leave brown tunnels in the root. Burpee Recommends: Introduce natural enemies to the area. Check with your Cooperative Extension Service for pesticide recommendations which must be applied prior to planting.
Wireworms: These insects live in the soil and kill seedlings by girdling their stems at the soil line, bore into stems, roots and tubers. They may be found around the stems in the soil are and ¼ to ¾ inch long, thin, yellow brown worms with a shiny skin. The adults are called click beetles, and are about 1/3 inch long, reddish brown with a hard shell. Burpee Recommends: Rotate crops. Check with your Cooperative Extension Service for pesticide recommendations which must be applied prior to planting.
What parts of my turnip are edible? The roots and leaves. Thinnings are great for salads.
How do I tell the difference between a turnip and rutabaga? Rutabagas are larger and yellow-fleshed. Turnips are smaller and white fleshed. Rutabagas take longer to mature and store longer.
Can I grow turnips in containers? Yes, they are fine for containers. Use a commercial potting mix rather than garden soil and give them plenty of room to develop their roots.
Why are my turnips woody and tasteless? Spring planted turnips must be harvested before warm weather. They are probably overripe.
My turnips turn brown in the middle, what is the problem? This could be from a boron deficiency. Have your soil tested. You can probably cut it out and still use the turnip.