The recent section 18 approval of Topguard for control of cotton root rot is not the end of the story, according to Dr. Tom Isakeit, Extension Plant Pathologist, it’s a continuation. The T-band application in the label is based on positive disease reduction and yield data from different locations, plus the lack of phytotoxicity. With a T-band application, (planter setup shown in picture) the chemical is not as concentrated around the seed as it would be with an in-furrow application. Although I’ve not seen phytotoxicity with our in-furrow application experiments, I know of one trial where it was reported when a rain occurred a few days after planting. Other methods of application can and will be examined in future experiments, but at present, growers are restricted to the current label.
In general, data so far suggests that the fungicide will work if it is placed around and above the seed. We have several good experiments behind us that indicate side-dressing is not effective, though. Our data so far indicates that when there is strong disease pressure, there is good control and a corresponding yield increase with the fungicide. In many of our trials, there was low disease incidence because of the dry weather, and so, there was no response to the fungicide.
More details about this new tool to control cotton root rot will be discussed at the March 1 meeting at the Research and Extension Center on HWY 44
