Carrot Pests, Diseases and Other Problems
Like most vegetable crops, carrots may attract critters that think they’re just as tasty as you do. Most of the pests listed here are not likely to be a problem for you. However, it’s best to familiarize yourself with them so you can quickly and effectively treat any problems with garden pests. Note that the most common pest for carrots is probably the carrot rust fly.
The University of Florida has a good site about common pests that affect carrots.
We of course recommend a natural or organic pesticide for any vegetable crops you grow. Here is a complete list of the pests to be on the lookout for:
Carrot root flies. These are worms that will attack carrots and other root crops. They feed directly on the roots. If you see these pests in your garden, harvest your crop immediately to avoid them spreading and living on after the harvest. Crop rotation and deeply tilling your soil can also help stop this pest.
Flea beetles. These pests will eat small holes in the leaves of carrots and other root crops. They also carry plant diseases, so be especially careful with these pests. Use an organic pesticide to control these pests.
Vegetable weevil. This pest feeds on the leaves of plants and usually attacks at night. This critter is gray to brown and grows to about 5 mm long.
Armyworms. This worm is a light green to yellow color, and sometimes can be light brown. They look like a common caterpillar and feed on stems and leaves. Look for them at night.
Parsleyworms. The parsleyworm is a yellow-green caterpillar with black bands are orange markings. These pests are visible during the day, but are fairly rare.
Yellow woollybear. This is another caterpillar-like pest. It has lots of white hairs along its main body. The larvae gather to feed on the leaves. As the larvae mature, they’ll begin to feed on other parts of the plant.
Vegetable leafminers. These pests resemble tiny yellow maggots. They “mine” through the leaves, leaving a trail in the leaf. Browning leaves and trails may mean the presence of many leafminers.
Aster leafhoppers and Six-spotted leafhoppers. These pests are yellow to green in color and have black spots on the head. Leafhoppers can carry plant diseases, so be careful to get rid of them quickly.
Tarnished plant bug. These are medium sized brownish bugs with antennae and a white marking on the back.
Wireworms. These pests attack attacks carrots and other root crops. Larvae are small, dark colored worms that resemble maggots. The adults are black beetles. They are also known as “click beetles.” Wireworms live best in moist soils, so don’t over water your garden.
Thrips. If you’re growing onions, be aware that onion thrips also feed on carrots. These tiny insects are yellowish to light brown.
If pests are a problem for your carrots, try out a natural or organic pesticide. Chemical pesticides can potentially cause health problems and can also contaminate the environment, especially when used incorrectly.
There are many natural pesticides available that are just as effective for your vegetable crops and don’t have the potential health or environment impacts as chemical pesticides.
Another natural technique you can use to deal with some insects is to use a row cover. A row cover will make it harder for flying insects to attack your carrots. Ask at your local nursery for a polyester row cover.
Common Carrot Diseases
There are a number of diseases that affect carrots that you should be aware of. The following is a list of common carrot diseases. Read the descriptions and familiarize yourself with the common symptoms. Remember, to prevent most soil borne diseases, don’t plant carrots in the same spot more than once every 3 years. To treat fungal diseases, try out a natural fungicide.
Aster Yellows. This disease is caused by aster leafhoppers. Look for stunted, yellow plants. Texas A&M has a full description of the disease here. Keep your garden weed free to help prevent this disease.
Black Root Rot. This is another fungus that attacks carrots via infected soil. This disease is most noticeable after harvest. It enters your carrots when they have a cut or crack. Wash your carrots well and store them in a cool place to help prevent this disease.
Damping-off. This disease is caused by a fungus that lives in the soil, and attacks mostly younger plants. Cooler moist weather will make this disease worse. Young plants will wither, brown, and may die off. Make sure you have well-draining soil.
Leaf Blight. This is a fungal disease that attacks the leaves of mature plants. Look for brownish decaying spots with yellow centers. The leaves may eventually wither and die. Make sure to clean up all infected leaves that fall to the ground as the fungus can survive the winter and infect plants the next year. High humidity can provoke the disease and cause the fungus to spore, so make sure to treat it early.
Leaf Spot. This fungal disease appears as small, dark circles on the leaves. Look for a lighter ring around the spots. The disease usually attacks later in the growing season.
Powdery Mildew. This is another fungal disease that looks like a white to gray powder on the leaves.
Root Knot Nematode. This disease causes galls on the roots and deformed roots. It is hard to identify as there are no real symptoms on the foliage of the plants. Rotate your crops often and make sure to keep your garden weed free
Other Carrot Problems
Growth Cracks. This problem is caused by incorrect irrigation of your carrot crop. Letting the soil dry out for two long or keeping it too wet may cause this problem.
Forked Carrots. Heavy or rocky soil may cause your carrots to form multiple forks. Transplanting seedlings is also not recommended for the same reason.
Limited Root Growth. Thinning your plants will help them to form deep roots. Avoid excessive nitrogen in the soil as well.
Green Tops. If the roots are forming too close to the soil level, the tops of your carrots may turn green with sun exposure. A layer of mulch 3-4 inches deep will help with this problem. Wait for the seedlings to appear before you add mulch, though.