By Darren Hefty
Fungicide use in wheat is growing very quickly in popularity due to the positive impact it has on profitability and yield. However, we are concerned about disease resistance to some of the fungicides currently on the market. We’ve seen disease resistance to the strobilurins like Headline, Quadris and Evito in wheat-growing areas of Europe and in the Mid-South of the U.S. Using combination fungicide products that contain more than one site of action is a good strategy to preserve the life of the fungicide products you are currently profiting from on your farm.
There are some great choices to use at herbicide timing and at flag leaf. Once you get to heading, we would only recommend using triazole fungicides. Here are some suggestions you may consider for your earlier spray timings.
HERBICIDE TIMING
We’ve almost always had good luck using a fungicide early at herbicide timing. There are a number of early season diseases like tan spot and septoria that can pop up. Since the wheat is very small, you can probably get by using a half rate of fungicide and lower water volumes (5-7 gallons) at this timing.
Rather than using a straight triazole (like Tilt, Bumper, Orius or Caramba) or a straight strobilurin (like Headline, Evito or Quadris), you can get both in combination products like Quilt (Quadris + Tilt), Stratego (Gem + Tilt), TwinLine (Headline + Caramba) or the new Custodia (Evito + Orius). You’ll be more effective on a wider range of diseases.
FLAG LEAF TIMING
Many wheat growers wait until heading to spray their fungicides so they can protect their crop from a potential head scab infection. However, a number of universities have shown an even better opportunity to make money by using a fungicide at flag leaf emergence. The flag leaf contributes a tremendous amount toward your overall yield, so it’s important to protect it.
At heading, you can only spray straight triazoles without risking an increase in the vomitoxin levels in your wheat. However, you can still use combination products that contain a strobilurin fungicide at flag leaf. Here are some products that will give you protection from rusts and other diseases at this critical timing: Priaxor (Headline plus the new carboxamide family product Xemium), Quilt, Stratego and Prosaro (Proline + Folicur).
ADDITIONAL NOTES
If you plan to spray at heading, your product choices are Prosaro, Caramba or Folicur (or the generic version called Orius). If you use one of these products earlier in the season, you need to read the label of that product before using it again because you will likely not be able to use a single product in this family more than once per season. So if you use Caramba early, like in the combination product TwinLine, then you will need to choose either Prosaro or Folicur (Orius) for your head scab protection or vice versa.