I am starting to see a fair amount of Target Spot in Mitchell County. Most of what I have seen is on older cotton, well past the 4th or 5th week of bloom. I have seen some on younger cotton between the 1st and 3rd week of bloom. This cotton will benefit from a fungicide application based on field history, irrigation, and growth stage.
Target spot, caused by the fungus Corynespora cassiicola, was first reported by Jones (1961) in cotton in Mississippi and not seen for nearly 40 years until it recently emerged in southwest Georgia cotton (Kemeriat et al., 2011).
It is now a disease we have to keep an eye out for each year. As of now this disease is not an automatic spray. Conditions have to be right for this disease to spread rapidly and cause yield loss.
If you are seeing a disease that looks like Target Spot and are unsure let me know! I can ID it no problem
We should take several factors into consideration when determining if we should spray or at least be aware of possible needed fungicide applications.
1. Is there a history of past problems or disease.
2. Does the cotton have rank growth and what is the current/future weather forecast.
3. Has Target Spot actually been discovered in the field.
4. What is the growth stage of the cotton. Fungicides should not be sprayed until the first week of bloom, no application is needed prior to this growth stage. The optimal time for a two application spray program is: first spray during first-second week of bloom and second fungicide application three weeks later. For a one application spray program, the most beneficial time is third week of bloom.
Fungicides that may be considered for application include: Headline @ 6 oz. rate, Quadris @ 6-9 oz. rate, and Twinline @ 7-8.5 oz. rate