Apple #413: Smut

At the request of an entirely anonymous Daily Apple reader, I give you more smut.

Wherever possible, the Apple Lady does try to fulfill all requests.

• Smut is a parasitic fungus that can infect many crops, but most commonly, corn, wheat, and onions.

• On corn, smut penetrates the tissue of the plant, especially on the leaves or the tassels, and develops into large balls, or boils, or galls. When the balls are broken, a great mass of black, greasy, powdery spores are released.

Smut balls on corn ears
(Photo from Cornell University)

• When smut grows on wheat, it is typically referred to as "loose smut." In this case, the smut has infected the plant to such an extent that instead of producing wheat flowers and pollen, it produces smut pods that release smut spores.

Loose smut, or Ustilago tritici
(Photo from Virginia Tech University)

• On onions, if smut infects the seedlings, the seedlings usually die within 3-5 weeks. Those onions that do survive a smut infection and produce bulbs will retain black streaks or lesions, which contain more spores.
  

Smut on a white onion.
(Photo from the Manitoba Weekly Vegetable Report)

• Mature onions that have been infected also tend to shrink more rapidly in storage and they are more susceptible to soft rot.

• If an onions has turned smutty, and if the flesh of the onion is still firm, you can wash off the black spores and still use the onion. However, it probably won't be as flavorful as a fresher, non-smutty onion.

• Smut spores are extremely hardy and can survive for several years even underground. The spores can be eaten by livestock, pass through the animal's system, and still go on to germinate and produce more smut.

Spores of the corn smut fungus
(Photo from the University of Georgia)

• Smut spreads and yields more smut most easily during hot, dry seasons. The hot air blows the smut spores farther and to more places, from one farm to the next.

• Smut spores do require moisture to grow. Once the spores land in the niches of a plant, if enough water has collected there, the smut will penetrate the tissue and spread.

• Smut is very difficult to control and likely impossible to eradicate. Even if every gardener and every farmer across the country stopped all work except to inspect all the plants for any smut balls, cut them out wherever they were found, and burned them; and even if every gardener and farmer did this three times a year, perhaps the amount of smut could be reduced.

• Varieties of corn have been developed that are especially resistant -- though not impervious -- to smut. These varieties include but are not limited to:

• Bellringer
• Capitan
• Sweet Rhythm
• Sweet Sue
• Country Gentlemen Hybrid
• Golden Gleam
• Golden Beauty
• Spring Gold

• Smut does not seem to like garlic, as none has ever been found growing on it.
  

• (Vampires don't like garlic either. Could there be a connection?)

• In some parts of the world, smut is considered a tasty treat. It is collected, sometimes canned, and sold in Mexico as huitlacoche.
  

• I was going to post a photo of huitlacoche for you, but I found the images so disturbing and unpleasant -- they gave me the willies, if you want to know the truth -- I decided not to. For those who are bold enough to look at a whole lot of smut, you can do so here. Don't say I didn't warn you.

• P.S. The word "smut" first means "black mark, or stain," and it comes from Germanic verbs that mean "to make dirty" or "defile." The second meaning, "indecent or obscene language," arose at nearly the same time as the first, in the 1660s.

Sources
Cornell University Plant Disease Diagnostic Clinic, Corn Smut Fact Sheet
Doctor Fungus, Introduction to Fungi
Virginia Tech University, Department of Plant Pathology, Physiology, and Weed Science, Wheat Loose Smut
Karen Delahunt and Walt Stevenson, University of Wisconsin Cooperative Extension, Onion Disorder: Smut
Purdue University Department of Botany and Plant Pathology, Diagnosis and Control of Onion Diseases
Online Etymology Dictionary, smut