Target spot and areolate mildew are present in a number of fields this year. At times, target spot and areolate mildew appear late enough in the season that the defoliation resulting from these diseases does not affect yield and use of fungicides is not needed.
Areolate mildew can easily be controlled using strobilurin products like Headline or Quadris, or mixed products like Priaxor or Elatus. If within 3-to-4 weeks of defoliating anyway, I would NOT use a fungicide. If the crop still had 4 or more weeks to go, I would consider weather, yield potential, how much disease is in the field and then decide to spray or not.
Target spot is a significant concern this year and is widespread. Not every cotton grower in the state needed to spray a fungicide for target spot, but I encourage growers to carefully consider their options. Target spot is of particular concern this year because
- the wet and warm conditions are perfect for an explosion of the disease,
- the disease has been found early in many fields, and
- the price of cotton makes protection 100-250 lbs lint/acre attractive.
The best window of opportunity for managing target spot is from the first week of bloom to the sixth week of bloom. When a fungicide program begins as early as the first week of bloom because of the disease situation; a second application may be beneficial two-to three weeks later. I don’t envision an application, follow-up or otherwise, after the 6th week.