Corn Smut and Truffles: Disease or Delicacy?

Photo taken by AJ Cann, 2/19/2012, Available on Flickr

I recently received some questions from a reader with accompanying pictures of a most disgusting, alien looking gray and black growth on their corn. If any of you have seen this on the ears of corn in your garden, as this picture shows, it can be quite astounding.  When a plant disease is big enough you can hear it mocking you and you think it may be growing eyes it sparks a bit of curiosity and possibly resentment. Would you believe that this alarming growth is also used quite intentionally in cooking and there is a good chance that you have probably eaten some? Why don't we get to that in a minute?

Corn Smut

For must of us trying to grow a few rows of our favorite sweet corn along the sunny garden path, this growth is considered a most undesirable part of our summer gardening experience. As a disease this is called corn smut.  Basically it is a fungal growth caused most commonly by the fungus Ustilago.  

Inside the smooth gray covering lies black spores of Ustilago. According to The Ohio State University these spores overwinter in the soil for up to 2-3 years. When the gray sac or gal ruptures these spores are carried to and fro throughout your garden and soil in any manner of different ways.  Combine this with warm temperatures and moisture in early summer and wa-la: you have corn smut. Growing like yeast, the fungus can be noticeable on your corn within ten days of infection.

SO NOW WHAT?

If you happen to have corn smut on your ears and you don't want to keep it in an effort to really add some pizazz to your fall door-step halloween decorations there are some things you should do.

• Remove infected plant parts or entire plants immediately. Remember the spores can live for 2-3 years in the soil so getting rid of them means putting the infected plants in garbage bags and throwing them away. Don't compost them.
• Be careful not to injure plants by cultivating too close to the roots and stocks. These injuries create openings where the fungus enters and then multiplies.
• Incorporate crop rotation. Don't plant corn in the same location in the garden every year, but switch everything around from year to year. This also helps with many other garden problems and diseases.
• Probably most important is to plant varieties of corn that are much less susceptible to corn smut.  Disease resistant plants can do the bulk of the work in reducing disease problems and pesticide use in most plants.

Mexican Truffle

Photo taken by Ross Grady 7.29.2011, Available on Flickr

Amazingly and quite interestingly in Mexican cooking this corn "problem" is a real delicacy. In Mexico and Mexican cooking is is called Huitlacoche (pronounced whee-tla-KO-cheh), corn mushroom, or Mexican Truffle.  According to the Tijuana, Mexico, restaurant Aqui es Texcoco, Huitlacoche has a smoky, earthy taste and is used in stews, tamales, quesadillas, soups, salads, and deserts. 

It's good for your health also.  Several journals, including Critical Reviews in Food Science and Nutrition and Food Chemistry have published research articles showing Huitlacoche has high levels of the amino acid Lysine, something corn has little of.  Lysine is an essential building block of proteins and plays a major role in a healthy body, yet the human body cannot produce it. 

And finally for the agricultural economists out there, further studies show Huitlacoche to be much more profitable than the corn it grows on. Millions of dollars have been spent in an effort to reduce corn smut from infecting commercial corn production.  Could you believe that some of the most fresh stages of corn smut being sold is bringing as much as $20 per pound?  

Now you can decide for yourself whether your corn fungus is a disease or a delicacy.  I suppose it depends on what you're in the mood for. 

Tomatoes: Rotten Tomatoes

Recently I was asked a question concerning tomatoes which appear to be rotting on the vine. I thought a blog post would be a good way to answer the question as many other people likely have seen this not uncommon problem, or are likely to in the future.

This picture, passed along to me, which is bound to make any gardener a little squeamish, shows the problem which is called Blossom End Rot.

Blossom End Rot on Tomato

Blossom End Rot

The symptoms include a sunken brown or black discoloration at the bottom of the tomato. This particular problem always starts at the blossom end of the tomato, hence it's name. This spot will increase in size with time. It is also very likely that the symptoms will manifest themselves on additional fruit on the same plant and possibly nearby plants as well.

Of the many possible problems a plant can get this one is unique in that it is a physiological problem. It is not caused by insect, bacteria, or fungus. In other words it is not solved by some kind of insecticide or fungicidal spray.  Being physiological, it is not contagious to other plants.

Blossom End Rot is caused by a lack of sufficient calcium during critical stages of fruit development.  Tomatoes get calcium from soil, pulling it in through their roots in solution along with water and other nutrients. Calcium is used by the plant in part to create more complex molecules which hold the cells together.

                                                                                      It's a sad tomato that can't hold it cells together.


CONTROL

Like most problems in life, as in plants, the best control is preventative. In most cases tomatoes don't get enough calcium as a result of dramatic changes in soil moisture levels. Plants whose roots go from really wet to extremely dry are much more likely to get Blossom End Rot. Not enough water in the soil decreases the amounts of calcium taken up by the roots. 

DO:

• Keep your tomatoes evenly moist, especially in times of drought
• Apply a well composted mulch around your plants to keep soil moist for longer periods
• Plant tomatoes in soil that drains well as water logged roots can cause similar problems
• Used a balanced fertilizer if and when needed
• Dispose of all affected fruit on the plant
• In extreme cases spray plants with calcium chloride solution every 10 days
• Keep the soil pH around 6.5 to free up more calcium in the soil. Too high pH ties up calcium

DO NOT:

• Cultivate or break up the soil around the plants roots
• Apply too much fertilizer high in Nitrogen. Too much fertilizer can cause plants to grow rapidly and magnify the calcium deficiency problem as fruit is developing
• Allow plants to dry out too much following periods of rapid growth

Blossom End Rot could be thought of as a tomato's version of tooth decay. Both are caused by calcium deficiencies and are also similar in that, as mentioned above, they are physiological issues. Too bad tomatoes don't drink milk, huh?

Blossom End Rot can also be present in eggplants and sweet peppers. The treatment and preventative measure would be the same as for tomatoes.

If you are seeing other problems with your tomatoes or any other plant you're trying to grow in your garden feel free to share pictures and questions with me and let them be the source for an upcoming blog post.