As in past years, your 2014 Cercospora Control program should include 3 sequential applications of fungicides to give you the greatest return per acre. Over the past 5 years, each additional application of fungicide, from 1 to 3, has returned greater revenue per ton and greater revenue per acre (chart 1) by keeping your crop healthier and allowing it to increase to its maximum potential both in yield and in sugar content (chart 2).
- Tank mixing of fungicides in the first two applications of a three spray program and in the first application of a two spray program should be strongly considered for best resistance management practices.
- Cercospora Leaf Spot control should begin when you first detect the presence of the disease.
- Headline should always be applied in late August for good Cercospora control and the added benefit of rapid canopy recovery after a frost occurrence during harvest.
Depending on the timing of the onset of Cercospora, your spray program options may look like one of these scenarios.
- In a three spray program, you should begin with a Triazole or Triazole + Tin, followed by Tin or Tin/Topsin, and followed by an application of Headline in late August. Topsin should never be used more than one time in a growing season due to the ability of rapid Cercospora resistance development to this fungicide.
- Only when weather conditions favor a later onset of disease development should you consider a two spray program. If this is the case for 2014, then in a two spray program, you should begin with one of the Tin products or one of the Triazole products. The preferred method would be a tank mix of both a Tin and a Triazole. Always use full rates of the tank mix partners for best resistance management. The second application in the two-spray program should be Headline in late August.
- In areas of the Red River Valley where only one application of a fungicide may be needed, then that application should be made using Headline in late August. A tank mix of Headline with Tin should strongly be considered to help prevent resistance development to Headline fungicide in these areas.