The decision to apply a fungicide in any given year weighs the risk of damage from the disease against the cost of a fungicide application. As the risk for disease has spread across regions and crops, discussions on the economics of disease management can be heard on farms across Canada. But despite a rainy spring in Eastern Canada and a dry summer across most of the Prairies, in 2019 disease incidence remained low across many crops, causing some to wonder — does a fungicide application pay?
“Many growers today are thinking ahead and planning for a fungicide application,” says Jon Weinmaster, cereal grower and channel marketing manager with Bayer. “With almost two decades of trial data at their fingertips through websites like ItPaysToSpray.ca from Bayer, growers can dig into the benefits of a fungicide application in dry and wet years. And today there’s even more technology available to help growers manage their operation to get even stronger returns on their investments.”
Weinmaster says the Climate FieldView digital farming software platform is a great example of this technology. It provides growers with exemplary data consolidation and analytics to help make decisions easier and validate them after. For example, detailed post-harvest functions help growers determine what fungicide timing and/or product gives them the best results. It can also detail the weather conditions present in previous years when disease struck.
“Last year was our first full year of being able to connect our fungicide performance to Climate FieldView and very easily show our customers that what we as a company are saying translates directly to their individual farms,” says Weinmaster. “Growers have always had access to our trial results, but when they see those same results on their own farm, well, it just means so much more.”
Backing up grower decisions
Last year Bayer backed up its data with its Prosaro XTR Yield Guarantee Program in Western Canada. It allowed eligible growers to compare results from a Prosaro XTR fungicide application against those of a competitor. All measurements were done using Climate FieldView. If Prosaro XTR didn’t out-yield the competition under the program parameters, Bayer would compensate growers for up to 160 acres of their purchase.
“Climate FieldView is an easy way for growers to consolidate and measure their data without having to do extra work,” says Weinmaster. “It’s got to be frustrating for growers and retails to have product suppliers walk in, all showing that their fungicides outyield the competition. Climate FieldView gives us an easy way to let our customers prove results on their own farm, and we encourage it.”
At the end of the season, growers can use Climate FieldView yield analysis tools to turn every field they track into a test plot to see what did and what didn’t work on their farm, and determine if changes are needed the following year. Growers can also look deeper into data layers to identify different areas of individual fields for further review to analyze the impact of their agronomic decisions year over year.
Getting the most out of your investment
“When it comes to cereals, growers need to start with a variety that has as strong a disease package as possible,” says Dr. Kelly Turkington, a plant pathologist with Agriculture and Agri-Food Canada. “Canola genetics now are able to manage blackleg quite well, although my canola colleagues indicate there are virulence shifts in the blackleg pathogen. No matter the crop, growers also need to choose seed that will help them mitigate their risk. Depending on your crop and your disease, there are different levels of resistance but it can be hard to find a variety that has a high level of resistance to all disease issues.”
Rotation remains one of the best ways to manage for disease in the soil, but what might be a preferred rotation for minimizing disease is not always economically feasible. Once a crop is in the ground, growers need to know what they may be facing as the season progresses.
“Growers can then look at the risk models and/or disease updates that show what diseases are in the U.S. or regions close to them — a good example of this is in terms of the cereal rusts where inoculum can come from the Pacific Northwest or from the Texas to Nebraska corridor,” says Turkington. “But then your next most important task is to be looking closely at your crop — watch the lower and middle canopy for signs of disease. For a single fungicide application in cereals you want to monitor leaf disease levels closely as the crop moves from stem elongation to flag leaf and then head emergence.
“If there is a moderate to severe level of leaf disease in the lower canopy and it is moving up into the middle canopy then an application sometime between emergence of the third leaf from the head or the flag leaf stage may be needed to protect healthy upper canopy leaf tissue. If there are few signs of disease then growers can monitor their crops and then look at an anthesis timing application of fungicide if warranted. If both early to mid-season leaf disease and fusarium head blight are a concern then growers may need to consider a dual application, on, at or before flag leaf emergence and then a second application after head emergence.”
Turkington also says that growers need to know what they are looking for when scouting for disease. “Growers need to know the difference between heat stress or damage from nutrition issues compared to disease damage,” he says. “In order to ensure you are applying a fungicide at the optimal timing, you need to know the biology of the disease and your plant.”
While sclerotinia and white mould can be found across Eastern and Western Canada, it hasn’t been as big of a problem in recent years, especially on canola. While this has reduced inoculum in the soil, the spores that cause sclerotinia have an indeterminate life cycle. Generally, growers who have experienced a loss to sclerotinia in even one season will pencil in a fungicide application, since given the investment into canola genetics, even a small percentage loss to disease can make a big difference on return.
“For both sclerotinia and fusarium head blight, you need to spray before you see symptoms so it is all about risk assessment,” Turkington says. “You need to know if the pathogen is established in the soil and you need to be watching the weather as well as accessing tools such as the Alberta Agriculture and Forestry/Alberta Wheat Commission fusarium risk maps. You can also use a risk checklist for sclerotinia stem rot, which evaluates risk based on disease history on your farm and your neighbour’s farm, weather conditions, and crop yield potential. Then it is about the timing. If you look at the quality and estimated yield of your crop and it has high potential, make sure you are timing your fungicide to get the most out of that application.”
This article was originally published in the 2020 Disease & Yield Management Guide, a Country Guide Special supplement sponsored by Bayer Crop Science.