Is Corn Smut Good or Bad? - Dengarden - Home and Garden
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Is Corn Smut Good or Bad?

Caren White is a Master Gardener and instructor at Home Gardeners School. She has been associated with Rutgers Gardens for over a decade.

Immature corn smut.  The galls are still white because they have not yet begun to fill with the black spores which will cause them to darken in color.

Immature corn smut. The galls are still white because they have not yet begun to fill with the black spores which will cause them to darken in color.

A gardener or farmer here in the U.S. who checks their corn crop and finds corn smut despairs. The crop is ruined and must be destroyed. A gardener or farmer in Mexico who checks their corn crop and finds corn smut is elated. A delicious treat for their table or market has appeared in their crop.

Why is the reaction different between the U.S. and Mexico?

What is Corn Smut?

Corn smut is a fungus (Ustilago maydis) that infects all parts of the corn plant. It won’t kill the plant, but it will reduce the yield. The fungus is spread through spores that fall to the ground where they can survive in the soil for up to seven years. When it rains, the spores are splashed onto the plants, infecting them. The spores can also be spread on the wind to infect corn that is not in the immediate vicinity. They can be spread too through the manure from animals who have eaten infected corn.

After the spores infect a plant, the fungus forms galls that range in size from a pea up to five inches. The galls form where the spores have landed on the plant and can appear on the stalk, the leaves or the tassels but are largest and most apparent on the ears. In the ears, the galls form between the kernels. This prevents the ear from completely filling with kernels, reducing the yield. The galls are white as they begin to develop but as they mature and fill with black spores, they turn brown or black. Fully mature galls rupture, spilling their spores on the ground. If it is a windy day, the spores will be blown on the breeze spreading infection to neighboring fields.

Mature corn smut filled with spores.  One of the galls has fully matured and opened revealing the black spores within which will either drop to the ground or be blown on the wind to infect more corn plants.

Mature corn smut filled with spores. One of the galls has fully matured and opened revealing the black spores within which will either drop to the ground or be blown on the wind to infect more corn plants.

How to Get Rid of Corn Smut

There is no treatment for corn smut. Once a plant has become infected the only remedy is to remove the entire plant immediately from your garden and destroy it. Don’t wait for fall cleanup. It is important to destroy the galls when they are young before they have formed spores that can spread the infection. Do not compost infected plants. This will only result in spores infecting your compost. The following year, you will be spreading the spores as you add compost to your garden.

The best “cure” is prevention:

  • Clean up and destroy all garden debris in the fall to prevent spores from overwintering in the soil.
  • Practice crop rotation. Plant your corn in a different bed every year.
  • Try planting sweet corn varieties that are bred to be resistant to the fungus such as Silver King, Seneca Sensation or Fantasia.
Fresh corn smut for sale in a Mexican street market.  Fresh galls can be eaten raw.  They taste similar to mushrooms which are also fungi.

Fresh corn smut for sale in a Mexican street market. Fresh galls can be eaten raw. They taste similar to mushrooms which are also fungi.

Is Corn Smut Edible?

Yes! In Mexico it is considered a delicacy. Mexican farmers will sometimes deliberately infect their corn crop to produce the edible galls. The galls are harvested when they are white before they mature and fill with spores. The galls can be purchased fresh in markets and stands or canned in grocery stores. The canned galls are usually used in fillings for tortillas and in soups. Fresh galls can be eaten raw. The taste is similar to mushrooms which are also fungi.

Empanada with canned corn smut filling.

Empanada with canned corn smut filling.

Attempts have been made to introduce this Mexican delicacy into the United States. The galls have even been renamed to Mexican Truffle to entice consumers. They have been slow to catch on perhaps because there is a very small quantity available thanks to the USDA which has devoted tremendous resources to eliminating corn smut from American corn. Maybe the USDA should instead devote some of those resources to encouraging Americans to eat corn smut rather than destroy it. It is certainly an organic solution to a common fungal infection.

Questions & Answers

Question: Can I still eat corn after removing the fungus?

Answer: Yes, the corn is still edible. There just isn't as much of it on the cob due to the fungus.

Question: Why is it important to remove corn smut and burn it?

Answer: Corn smut is a fungus that reduces the yield of your corn and results in deformed ears of corn. The best way to get rid of it is to remove it from your plants and burn it. Burning it destroys the spores by which it reproduces. If you put it in your composter or just throw it away, you are spreading the spores instead of destroying them.

© 2017 Caren White

Comments

Caren White (author) on August 30, 2020:

I'm afraid that I don't know anything about chickens. But bear in mind that corn smut is a fungus. Is it safe to feed fungus to your chickens?

Frank on August 29, 2020:

Can my chickens eat the smut?

Caren White (author) on August 16, 2020:

If you want to rid your garden of corn smut, you must remove all the plants that are infected with it. You can keep all the plants that don't show signs of infection. The spores reside in the soil so other plants may become infected in subsequent years.

Anna Vest on August 16, 2020:

Do I need to throw all the corn away or just the ones I see the corn smut on?

Caren White (author) on August 07, 2020:

Corn smut is a fungus so it doesn't matter what plant it is growing on. You can eat corn smut that grows on sweet corn or feed corn.

Maureen Henrikson on August 06, 2020:

Hello, do you know if eating the corn smut off of feed corn is any different than eating it off of sweet corn?

Caren White (author) on November 09, 2017:

Glad you found it helpful. I think corn smut has been around in the US longer than the USDA. Thanks for reading and commenting.

Mary Wickison from Brazil on November 09, 2017:

I am surprised the US ever allowed them in, as their rules are stringent. I think it was in the 70s or 80s when the Mediterranean fruit fly was found in California. The whole of the LA basin (crops and houses) were sprayed by planes with insecticide. California is called the breadbasket of America and any potential threat to crops would be devastating to the ecomony.

I've never seen such a thing before and I grew up around many cornfields, although there was spraying.

My neighbor says I should try growing corn this year here in Brazil. Now if I see this fungus I will recognize it.

Seven years is a long time for it to stay in the ground. This was very interesting and now I'll stay on the alert for it.

Caren White (author) on November 08, 2017:

Demas, you're welcome! Thanks for reading and commenting.

Demas W Jasper from Today's America and The World Beyond on November 08, 2017:

An interesting Hub devoted to a specialty concern. Thanks.