Recent Issues

November 2011

General

Sweet Potato or Yam?
Combatting Japanese Beetle with Less Pesticide

Other Sections: Gardening Health and Nutrition

Sweet Potato or Yam?

As the holiday season approaches, it seems appropriate to discuss the issue of sweet potatoes versus yams. Rhonda Ferree, University of Illinois Extension educator, horticulture, says that officially a sweet potato is never a yam, but that sweet potatoes are often referred to as yams.

Sweet potatoes (Ipomoea batatas) are yellow or orange tubers that elongate into ends that taper to a point. There are two types of sweet potatoes, which creates the confusion over yam versus sweet potato. The paler-skinned sweet potato has a thin, light yellow skin with pale yellow flesh which is not sweet and has a dry, crumbly texture similar to a white baking potato. The darker-skinned variety (which is most often called "yam" in error) has a thicker, dark orange to reddish skin with a vivid orange, sweet flesh and a moist texture.

The people in one of the highlands of western New Guinea are reported to subsist almost entirely on sweet potatoes. One medium (5" x 2") boiled, peeled sweet potato provides more than twice the recommended daily allowance of Vitamin A for an adult, 36% of the Vitamin C and a good amount of other vitamins and minerals. Sweet potatoes may be boiled, baked, browned, fried and candied. They can be used to make biscuits, breads, muffins, pies, custards, cookies, and cakes.

Ferree says that most of us have probably never seen a true yam. The true yam is the tuber of a tropical vine (Dioscorea sp) and is not even distantly related to the sweet potato. The yam is a popular vegetable in Latin American and Caribbean markets, and is slowly being introduced here. The true yam is actually even sweeter than the sweet potato, and the tuber can grow over seven feet in length. The yam tuber has a brown or black skin which resembles the bark of a tree and off-white, purple or red flesh, depending on the variety.

On another note, sweet potato vines are becoming increasing popular for their ornamental value as ground covers, hanging baskets, in planters, and even in bottles of water in the kitchen. The ornamental vine's tubers are edible, but are reported to have a bland taste.

In the end it doesn't really matter what you call it. Regardless of whether you call them yams or sweet potatoes, enjoy them often - they're healthy and tasty choices for your kitchen table.

Combatting Japanese Beetle with Less Pesticide

Pest management continues to be an important issue in the garden and field, and pesticides tend to be the popular remedy for such problems. Summer infestations of the Japanese beetle highlight the pest management dilemma faced by area residents. How can residents improve Japanese beetle management while decreasing overall pesticide use? U of I Extension initiated a comprehensive program in 2011 to help them do just that.

Japanese beetles are a recent arrival to central Illinois. Although they have been present in the state for decades, they began a westward trek during the late 1990s that eventually brought them to our doorstep. Ravenous feeders, they congregate in mass – defoliating plant material and clipping silks.

Extension encouraged homeowners to refrain from using traps (which draw in the pest) and to apply pesticides on a limited number of plants (a triage approach to management). In the field, Extension noted that beetles tend to cause field-edge rather than field-wide yield losses. Farmers were encouraged to only spray if yield was not yet "set" and if beetle distribution was both intense and uniform. A similar Springfield-area program cut aerial pesticide applications in half in 2003.

2011 programming included face-to-face meetings, field visits, and interviews with local media. Examples include a feature story on WEEK-TV, columns in the Pekin Daily Times, articles in Illinois AgriNews and the Daily Illini, interviews with the Peoria Journal Star and the Illinois State Journal Register, and live broadcasts on Illinois RFD Radio and WIRL. Examples can be viewed at the following websites: http://web.extension.illinois.edu/state/newsdetail.cfm?NewsID=25950 http://www.centralillinoisnewscenter.com/news/local/Japanese-Beetles--To-Spray-Or-Not-To-Spray-125860659.html?vid=a.

For more information about Agriculture and Natural Resource programs in the Fulton-Mason-Peoria-Tazewell unit, please contact Matt Montgomery, Extension Educator, Sustainable Agriculture atmpmontgo@illinois.edu or 309-547-3711.

For more information about Horticulture programs in the Fulton-Mason-Peoria-Tazewell unit, please contact Rhonda Ferree, Extension Educator, horticulture at ferreer@illinois.edu or 309-543-3308.