Taming Root Rot

 

Cotton root rot is the limiting factor to a booming apple industry in Texas. I once visited an apple grower in the Hill Country who said he was losing up to a thousand trees a year to cotton root rot, and there is nothing modern science can do to stop the loss. Cotton root rot is also devastating to grapes, peaches, plums, and most other fruit trees. The nursery industry is also hit hard because the rot attacks many ornamental plants.

This soil fungus destroys a large percentage of the cotton planted in the southern part of Texas. It got its name because it attacks cotton so virulently. The fungus is only active in soils with a pH above neutral when soil temperature gets above 82°, so it is often found in the alkaline soils of South Texas.

Millions of dollars in agricultural and horticultural crops are lost each year, and millions more have been spent researching ways to control cotton root rot. Sulphur has been used at the rate of 43,560 pounds per acre and worked a foot deep into the soil trying to lower the pH, but the roots always manage to work themselves below the sulphur and get the rot anyway.

Soil fumigants have been used with some degree of success, but they are very damaging to the beneficial soil life and the control is short-lived. Fumigants are also impractical on large acreage. Aerating the soil helps some, but we don't have equipment powerful enough to aerate as deep as the fungus lives.

Good farmers know that a soil balanced in minerals and with a lot of decaying organic matter in the soil is the best deterrent to insects and diseases, especially soil-borne diseases. The common use of high nitrogen fertilizers, however, speeds up the organic decomposition in the soil and the use of herbicides never allows wild plants to contribute to the organic content. As a result, there is rarely enough organic matter accumulated in the soil to get all the life forces working that could hold cotton root rot in check. As a result the search continues for a cure-with most of the research money being spent on some man-made product or technique that isn't in tune with Nature and probably won't work.

In studying Nature, you quickly learn that every living creature has a natural enemy to hold it in check. But these checks and balances only work when the whole environment is in balance. I believe cotton root rot can be held in check with the use of beneficial soil microbes.

Those microbes capable of stopping the troublesome fungus may have already been discovered. As this book is being made ready for press, I am testing a microorganism given to me by Bill Kowalski of Natural Industries, Inc., of Houston.

Mr. Kowalski came to my office and said he had a product I might want to try. It was a natural microbe discovered by Dr. Don L. Crawford of the University of Idaho, which he isolated from the roots of a linseed plant. And this microbe produced potent antifungal metabolites. Tests showed that it inhibited a wide range of fungi-most of which I can't spell or even pronounce!

Cotton root rot, the fungus that causes the biggest problem in this area, wasn't mentioned in the study. After questioning, I found out that the microbe had not been tested for root rot, so I volunteered to do a test.

We always plant a lot of our special okra, so we have plenty of seed to share with our friends and customers. Okra is the perfect test plant for this microbe. It is related to cotton and is very susceptible to cotton root rot. When we moved onto this farm, we found the fields thoroughly contaminated, and in twenty-five years of trying, we haven't been able to eradicate it. We seem to have been able to suppress it some, though, since the okra lives longer into the summer than it once did.

For this test, we planted okra seeds in mid-April, and by the end of June, I could see a difference between the plants that were treated with the microbe and those that were not. The treated rows were more uniform in growth and a little taller. By mid-July, the treated rows were averaging a foot taller and looked a little healthier. With the soil temperature rising, I suspected that the cotton root rot was becoming active. It was time for a root inspection.

The first plant I pulled up in the control (untreated) row was infected with the fungus. I continued pulling up the poorest looking plants and found every one of them was infected, some more than others.

I next checked the treated rows by pulling up an equal number of plants, and I tried to find the poorest looking plants, but I found the roots on every plant in these rows were perfectly healthy.

I was so thrilled with the results I was finding, that I pulled up and inspected over fifty plants from each row. The results continued the same, and I also noticed fewer nematodes on the roots from the treated rows.

This product, now given the name of Actinovate™, is the first thing ever to give me this level of control. Besides the cotton root rot, Dr. Crawford said his test in the lab showed this product also strongly inhibits Phythium, Rhizoctonia, Pythophora, Postia, and Scherotinia. To a lesser degree, it inhibits fungi such as Fusarium, Geotrichum, and Verticillium. (Actinovate™ is Steptomyces Lydicus strain WYCE108, which is a Saprophytic, rhizo-sphere-colonizing actinomycete-for those of you who are scientifically minded.)

I have also been given another natural soil microbe that has been tested on cotton root rot. According to a good friend, this microbe when used properly also gives excellent control of the fungus. My friend, whose opinion I greatly respect, says using this microbe in areas where no root rot exist, produces healthier and more productive plants, probably because the microbe has a variety of important, beneficial tasks it performs in the soil of which we are not yet aware.

This last product wasn't discovered by a Ph.D. at a university, but by a farmer named Frank Cavazos, who lives down in the Rio Grande Valley at Mercedes, Texas. Frank hasn't given his microbe a scientific name, but just calls it F-68™ , because he discovered it in 1968. Until lately he didn't have the resources to grow it and get it on the market.

 

Beneficial microbes such as these occur naturally and thrive with organic farming practices in organically rich soils. I believe root rot and many other troublesome soil diseases can be controlled by using microbes in a natural way, but these good microbes may need a little help from us. For example, we can place them where they are needed just as we place a few more beneficial insects in areas when they are needed. By maintaining a high organic content in the soil and abandoning the practices such as pesticides and chemical fertilizers that destroy soil life, these beneficial microbes will grow and prosper and make our gardens and farms healthier and more productive.

The Garden-Ville Method  - Lessons in Nature