One of the most devastating diseases of cotton is a disease commonly known as Cotton Root Rot, caused by the fungus Phymatotrichopsis omnivora.  This pathogen is one that can attack many different plants and is quite aggressive on many.  In the landscape, this disease have done much damage to ornamental pears, lacey elms, pittosporiums and others.  The devastating effect of this disease is noted in history of Texas. In Northeast Texas (around the Dallas-Fort Worth area and some parts of the blacklands (along the I-35 corridor) in Central Texas used to be lots of cotton acreage.  Over many years since 1930s, this disease has devastated the cotton plant with no good remedy for it.  It has always been the challenge to a plant pathologist or the agronomist to look for solutions to this pathogen.  Old suggestions include incorporating more organic matter or long term rotation to reduce incidence. But these approaches is not too friendly to the push to produce quality products in large quantities and consistently every year.  Over the years, cotton acreage has decreased.

Aerial photo of a cotton plot. The bare (brown areas) are dead cotton plants.

The latest in the fight against cotton root rot is the utilization of chemical fungicide to protect the roots. Recently, a product called TopGuard (active ingredient: Flutriafol) was given a FIFRA section 18 exemption to legally use this fungicide (originally developed to battle Asian Soybean Rust) on cotton. Research that went into the data for the section 18 exemption was performed by one of our own in the Department of Plant Pathology & Microbiology at Texas A&M – Extension plant pathologist, Dr .Tom Isakeit.   It was interesting to note that Tom also mentioned that proper timing and dosing is important to the management of this pathogen. The research for this product’s efficacy began in 2008. Even after 3 years of data, there is still much needed to see how it continues to perform and if there are tweaks to better use it.  Also, the additional research is need to see how the product works in the different conditions of Texas (note: last year was really dry!).  Read more about Dr. Isakeit and Topguard (click here).  Also check him out on a application tutorial video.   

NOTE: this is currently a section 18 for cotton growers.  This IS NOT a permission to use this product on all type of plants against cotton root rot.  We have no idea how some of the other plant affected by cotton root rot will react with this chemical.  Research must be done to find the answers.