sweet potato, trailing perennial plant (Ipomoea batatas) of the family Convolvulaceae (morning glory family), native to the New World tropics. Cultivated from ancient times by the Aztecs for its edible tubers, it was introduced into Europe in the 16th cent. and later spread to Asia. It is now the most important of tropical root crops and is grown in many varieties (differentiated by their leaf shapes). In the United States it is cultivated chiefly in the South, though a few hardy varieties are grown as far north as Massachusetts. Sweet potatoes are used mostly for human consumption but are sometimes fed to swine. They yield starch, flour, glucose, and alcohol and are especially rich in vitamin A. The sweet potato is sometimes confused with the yam, which belongs to another family. Sweet potatoes are classified in the division Magnoliophyta, class Magnoliopsida, order Solanales, family Convolvulaceae.

potato beetle, name for two beetles of the leaf beetle family and for two of the blister beetle family, all destructive to the potato plant and its relatives. Most notorious is the Colorado potato beetle, or potato bug (Leptinotarsa decemlineata), a black-and-yellow striped member of the leaf beetle family. It was once confined to the Rocky Mts., where it lived on wild members of the nightshade, or potato, family. When settlers introduced the Irish, or white, potato (c.1855), the insect spread through most of the United States and then to Europe. Its orange-yellow eggs are laid in clusters on the undersides of the leaves, on which the reddish, black-spotted larvae feed. Pupation (see insect) takes place on the ground, and the adults emerge to feed on the potato plants; they hibernate underground during the winter. The destruction caused by the Colorado potato beetle has been one of the chief reasons for the development of insecticides; Paris green and other arsenic compounds have been used extensively. A member of the same family is the three-lined potato beetle (Lema trilineata) of the E United States, sometimes called old-fashioned potato beetle. The adults are yellow-orange with black stripes and lay their eggs scattered randomly over potato leaves. Two blister beetles of the genus Epicauta are also known as old-fashioned potato beetles. They are slender insects with complex life histories, passing through several larval stages before pupating. They feed on potatoes, tomatoes, and other members of the nightshade family. One (Epicauta vittata) has orange and black stripes and is also called striped potato beetle, or striped blister beetle; the other (E. marginata) is black with gray margins. The various potato beetles termed "old fashioned" were considered major pests before the spread of the more destructive Colorado potato beetle. Potato beetles are classified in the phylum Arthropoda, class Insecta, order Coleoptera. The Colorado potato beetle and the three-lined potato beetle are classified in the family Chrysomelidae and the old-fashioned potato beetles (Epicauta) in the family Meloidae.

potato or white potato, common name for a perennial plant (Solanum tuberosum) of the family Solanaceae (nightshade family) and for its swollen underground stem, a tuber, which is one of the most widely used vegetables in Western temperate climates. The plant is probably native to the Andes, where it was cultivated by the Incas. In pre-Columbian times its culture spread widely among Native Americans, for whom it was a staple food.

Its history is difficult to trace, partly because the name potato was also used by early writers for the sweet potato (Ipomoea batatas) and for other unrelated plants. Spanish explorers are believed to have brought it in the 16th cent. from Peru to Spain, whence it spread N and W throughout Europe. It was brought to North America by European settlers probably c.1600; thus, like the closely related tomato, it is a reintroduced food plant in the New World. The potato was first accepted as a large-scale crop in the British Isles. It became the major food in Ireland during the 18th cent. and is hence often called Irish potato to distinguish it from the sweet potato. Ireland was so dependent on the potato that the failure (resulting from blight) of the 1845-46 crop caused a famine resulting in widespread disease, death, and emigration. The potato was also important to the course of history in the 20th cent. in Europe, especially in Germany, where it kept the country alive during two world wars.

The potato is today a primary food of Western peoples, as well as a source of starch, flour, alcohol, dextrin, and fodder (chiefly in Europe, where more is used for this purpose than for human consumption). Nutritionally, the potato is high in carbohydrates and a good source of protein, vitamin C, the B vitamins, potassium, phosphorus, and iron. Most of the minerals and protein are concentrated in a thin layer beneath the skin, and the skin itself is a source of food fiber; health authorities therefore recommend cooking and eating potatoes unpeeled.

The potato grows best in a cool, moist climate; in the United States mostly in Maine and Idaho. Russia, Ukraine, Poland, Germany, and Belarus are the greatest potato-producing countries of Europe, and China and India are now (with Russia) among the top three potato growers. Potatoes are usually propagated by planting pieces of the tubers that bear two or three "eyes," the buds of the underground stems. The plant is sensitive to frost, is subject to certain fungus and virus diseases (e.g., mosaic, wilt, and blight), and is attacked by several insect pests, especially the potato beetle. Potatoes are classified in the division Magnoliophyta, class Magnoliopsida, order Polemoniales, family Solanaceae.

Colorado potato beetle: see potato beetle.

Food plant (Ipomoea batatas; family Convolvulaceae) native to tropical America and widely cultivated in tropical and warm temperate climates. Botanically unrelated to the white, or Irish, potato or the yam, sweet potatoes are oblong or pointed oval, tuberous roots. Skin colour ranges from light buff to brown to purplish red; the pulp may be white (highest in starch) to orange (also high in carotene) to purple. Long, trailing plant stems bear funnel-shaped flowers tinged with pink or rose violet. Sweet potatoes are served baked or mashed and used as pie filling.

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or potato bug

Leaf beetle (Leptinotarsa decemlineata, family Chrysomelidae) native to western North America. It began feeding on the leaves of cultivated potatoes when the plants were introduced into western North America, and by 1874 it had become an important and widespread pest. It has a hemispherical body, about 0.4 in. (10 mm) long, and is orange-red or yellow, with black stripes on the wing covers. Depending on climate, potato beetles may produce one to three generations each year.

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Destructive species (Lema trilineata) of leaf beetle (family Chrysomelidae). Less than 0.25 in. (6 mm) long, it is yellow and has three black stripes on its wing covers. Eggs are laid on the underside of a potato leaf, on which both larvae and adults feed. The larvae are camouflaged by excrement the beetles pile on their back. Two generations are produced each year; the second overwinters in the ground in the pupal stage. Seealso Colorado potato beetle.

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Herbaceous annual (Solanum tuberosum) in the nightshade family. One of the world's main food crops, the potato differs from other food crops in that the edible portion is a tuber. Highly digestible, potatoes are prepared for eating in many ways and are a major source of starch as well as amino acids, protein, vitamin C, and B vitamins. The stem grows 20–40 in. (50–100 cm) tall, sprouting spirally arranged compound leaves. Underground, stems extend as stolons, the ends of which enlarge into 1–20 tubers of variable shape and size. The tubers have spirally arranged buds (eyes) that may remain dormant after the tuber is fully grown for up to 10 weeks or more; they grow into plants identical to the parent plant. A native of the Andes, the potato (also known as the common potato, white potato, or Irish potato) was carried by Spaniards into Europe during the 16th century. A century later, it had become the major food crop in Ireland; disastrous damage to the crop by a fungal blight caused the Irish potato famine in the mid-1800s. Seealso sweet potato.

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