Whatever shall we do with all the smut that relentlessly infiltrates the heartland
of America? That depends on what kind of smut you're talking about. This
week's Cool Science Image is corn smut (the common name of the fungus
Ustilago maydis). Smut may be a four-letter word, but its mycological meaning
is not scandalous. To U.S. farmers, smut is poison, and infected ears are fed
to cattle. To 30 million Mexicans, "smut" means "Tasty!"
From Iowa to Ohio, fresh sweet corn is revered as a true taste of summer. But imagine walking into your garden or field and finding nasty gray blobs on the stalks, flowers or ears of your corn. You might be grossed out and proclaim your crop ruined. A thousand miles south of the American cornbelt, in the central Mexican highlands, many farmers cultivate corn for the express purpose of encouraging smut. Known as "cuitlacoche" or "huitlacoche" in Mexico, smut is sold canned throughout Mexico and America. It may not look yummy to most of us, but smut aficianados praise the fungus for its rich earthy-corny flavor.
The smut fungus lives in the soil (along with millions of other microbes). The growing points of corn (meristems) include the base of internodes, the base and midrib of leaves, and young ears. These tender tissues are delicate and susceptible to infection by smut, which is splashed onto the plant by rain or blown on to the plant by heavy winds. Early season drought also makes young corn susceptible to infection. The tumor-like structures, or galls, produced by the fungus are covered with greenish-white to silvery-white tissue, and their insides age into a mass of powdery, darkened spores.
If you can't beat 'em, join 'em. Next time the garden gives you gray, misshapen ears of sweet corn, take a walk on the wild side and saute the offending fungus in some olive oil and serve with scrambled eggs. Or try this smutty soup recipe. Yum... .
Image courtesy the UW-Madison Department of Botany.
