The Spraying Question - Four Factors that Inform Key Fungicide Decisions

Deciding what to spray, when to spray or even if you need to spray a fungicide can be a complex set of decisions. Colette Thurston, an Alberta-based market development agronomist with Bayer, offers growers the four factors she considers when making these key fungicide decisions.

1. Know Your Farm, Crops, and Diseases. While it may seem simple, knowing the particular risk factors your crops face is key to making the best fungicide choices. One of the first questions you should ask is, “What diseases should I be worried about?” This question breaks down into three parts: 1) What diseases represent a likely risk to your crop? 2) What fungal diseases are more prevalent with your current crop rotation? 3) What diseases have affected your crops in the past? Knowing the common enemies your crops may face is one of the most important steps you can take to making the right fungicide decision for your crops. The Bayer Fungicide Selection Tool available on the Bayer website is an excellent resource to help at this stage.

The risk of disease outbreak depends on three interconnected factors: weather, the presence of the pathogen and the susceptibility of the host plant or crop.

2. Consider the Weather Conditions. This is one of the first things many growers consider, and for good reason. “I always look at the weather conditions, especially the temperature and moisture conditions.” Thurston says. When it’s getting close to spray time, I always recommend looking at the seven- to ten-day forecast to consider the near future.” While weather is a critical factor, it’s important to note that that weather be only one of many factors to consider. While the decision to not spray can sometimes be the right choice in a dry year, it isn’t always the case. If in doubt, growers should check with their local market agronomist about how much weight to give to weather in a crop year.

3. Lean on Local Data. “No two farms are the same,” Thurston says, “but one of the benefits of speaking with a market development agronomist is that we're able to provide people with local trial data.” When considering disease pressure or weather conditions, it can be easy to find data, but it is often regional rather than local. There is no replacement for a truly local approach. “This is one of the places where Bayer shines,” she adds. “I’m happy we’re able to provide local, multi-year data for our growers.” Key local data can also include yield under similar weather conditions in prior years.

4. Weigh All Fungicide Options. Not every year is the same. It’s important not to look for the best possible fungicide, but the best fungicide for this years weather conditions for your crop. At Bayer we recommend products like Prosaro Pro and Proline Gold when disease pressure will be high. In lower disease pressure situations growers may want to consider Prosaro XTR or Proline. Bayer also has a flex timing fungicide that enables growers to apply that fungicide when its needed the most whether that’s at flag leaf or heading. Even in dry years, Thurston recommends connecting with local market agronomists and thinking carefully about whether you need to spray. Choosing the right fungicide for the weather conditions in your area and applying that fungicide at the right time can really boost ROI.”

With these four factors as your guide, be sure your decision to spray for fungal diseases makes good business sense.