Daucus carota is a member of the Umbelliferae (parsley) family along with celery, fennel, cumin, and dill. Carrots were reportedly first grown in Rome in the third century, then in Afghanistan before being cultivated by the Dutch.
Early varieties were purple until our ‘modern’ orange version was cultivated in the Netherlands. There are dozens of carrot varieties worldwide in several widths, colors, and lengths. Color variations other than orange include white, yellow, reddish-hued, purple, and nearly black.
TYPES & VARIETIES
Carrots are classified based on their length and shape as follows: Imperator are long with thin shoulders and a tapered tip; Danvers are large and generally medium length; Nantes are also medium in length but with a rounded tip; and Chantenay are short and broad shouldered.
Popular cultivars by size include Orbit and Thumbelina for small, round carrots; Baby Spike, Littlefinger, Minicor, and Short ’n Sweet for baby carrots; Red-Cored and Royal for Chantenay; Half-Long and 126 for Danvers; Bolero, Ingot, Coreless, Scarlet, Sweetness, and Touchon for Nantes; and Avenger, Gold Pak, Legend, Orlando Gold, and Tendersweet for Imperator.
References: Agricultural Marketing Resource Center, University of Illinois Extension, Washington State University Extension.
PESTS & DISEASE
Aphids can damage carrot crops throughout the production process; insects will feed on the carrot and serve as a vector for other diseases.
Root knot nematodes feed on roots, causing stunted growth and deformation. Populations are typically largest around harvest time.
To control the carrot rust fly, experts recommend eradicating weeds around fields as the fly commonly feeds and breeds on weeds. Avoid crop rotation with other susceptible vegetables such as parsnips and celery.
Other harmful pests include beetles, caterpillars, crickets, fire ants, fleahoppers, leafhoppers, spittlebugs, stink bugs, thrips, weevils, and whiteflies, all of which can be particularly damaging to seeds and in all stages of plant development.
Pythium blight may result in stubbing, root forking, dieback, or the growth of white mycelium fungus that may develop into watery soft rot under moist conditions.
Rhizoctonia is a bacterial infection that causes the development of brownish-black lesions on the taproot. The disease is exacerbated by wet, cool conditions and is best prevented by crop rotation and good agricultural practices.
The soilborne fungal disease cavity spot may lead to the loss of an entire crop. It can be identified by brown, water-soaked lesions that may expand and dry as the carrot matures. Cavity rot is more likely in fields with prior carrot or alfalfa plantings.
A selection of other diseases that may damage carrot crops include anthracnose, leaf black root, blight (Alternaria, bacterial, early, and seedling), canker, damping off, mildew, leaf spot, mold (grey, white), mosaic viruses, root knot, root rot, and types of scab.
References: University of California Vegetable Research and Information Center, University of Florida/IFAS Extension, University of Georgia Extension, Washington State University Extension.