In over 200 replicated, field-scale fungicide trials across the prairies in the past eight years, there is overwhelming evidence of a noticeable yield advantage when applying a fungicide on cereal and other crops including canola, even in times of low disease pressure
In 2015, growing conditions across much of the prairies were not conducive to the development of disease. The weather was dryer than usual, with low humidity and little precipitation. Given these conditions, some growers decided to save their money and forego a fungicide application. Unfortunately, in many cases, that was not the best decision.
“Last year application intensity was down, more so for canola than for wheat,” says Al Eadie, market development manager with Bayer.
“Disease levels were lower, but it was still happening, and in particular the intensity of fusarium surprised people.” Those farmers who used a fungicide were protected. For those who didn’t, last year’s trial results showed that without a fungicide application, canola yield was down an average of 4.5 bushels per acre.
In the past, the decision to apply a foliar fungicide depended on where you farmed. For instance, Manitoba growers usually include a fungicide application as part of their annual cropping plan because they know disease pathogens are present. And as disease and intense crop production practices have spread west, so has the need for disease control.
In recent years, growers in Saskatchewan have been grappling with fusarium as well as increased incidences of leaf disease. Fusarium pressure has also increased in Alberta, with affected areas spreading each year.
“If you are taking a ‘wait and see approach’ as to whether you should do a fungicide application in wheat, it can be a tough call,” says Troy Basaraba, market development specialist with Bayer. “If you wait until you see signs of the disease, often the crop is too advanced for it to make a difference. Even if a crop looks clean, you never know what’s coming in the weeks ahead. If you get a shot of rain at heading then everything changes.”
Bayer has conducted over 200 replicated field-scale cereal fungicide trials in the past eight years, across all prairie provinces and growing regions, completing 127 wheat, 42 barley and 23 oat trials, as well as trials on soybeans, dry beans, peas, lentils and canola. In virtually every crop, there was a positive return on investment from a fungicide application, and the worst case scenario was a break even result.
“Our results are broken into three scenarios: up to 85 per cent of normal moisture, 85 to 115 per cent moisture, and greater than 115 per cent moisture,” says Eadie. “We have a big dataset now with overwhelming evidence that there is a noticeable yield advantage when applying a fungicide on cereal crops under all of these scenarios.”
One scenario used a Prosaro fungicide application at head timing. On average, this trial revealed an 8 bushels per acre advantage over the untreated check in Alberta; a 7 bushels per acre advantage in Saskatchewan; and an 8.3 bushels per acre advantage in Manitoba. Despite the climate differences and changes in growing conditions, the advantage was similar across every region.
“On average, we’ve seen consistent levels of yield response no matter where the trials were conducted,” says Basaraba. “Now we’re also looking at when you should apply that fungicide. The message has always been to protect the flag, but we are seeing advantages in yield and grain quality when a fungicide is applied at the head, he adds. “We’re talking a seven-to 10-day timing difference that could make a noticeable difference on your bottom line.”
Trial data showed that when a fungicide was applied at flag leaf, it achieved a better grain grade over the untreated check six to12 per cent of the time. When it was applied at the head, a better grain grade was achieved 22 to 24 per cent of the time.
“If you are already seeing signs of disease at the flag, then deal with it,” says Basaraba.
“But if things are looking relatively clean, wait for the head timing and protect both your yield and quality.”
Control disease on all crops
While the decision to apply a cereal fungicide is relatively straightforward, the decision to apply a foliar fungicide on canola takes a bit more consideration. While some growers choose to wait, conditions can quickly change during flowering. At the 20 to 30 per cent flowering stage last season, growers were very pessimistic about their yield potential. But favourable weather during the latter flowering stages resulted in 10 bushels per acre they hadn’t counted on. However, during that time it rained enough for moisture to develop in the canopy and encourage sclerotinia development in some areas.
“Basically, if you have a good looking crop, we’d recommend you spray,” says Basaraba. “How much value you get from that application really depends on whether or not it’s a bad year for sclerotinia. But for those years when sclerotinia is bad, it more than makes up for years when there is only a slight advantage.”
In 2015, Bayer also conducted 12 trials on peas in western Canada. “It was a light year for disease, but we still saw on average, a three bushels per acre yield advantage when Delaro was applied,” says Eadie. Under similar conditions Delaro proved a 4.5 bushel yield increase in 12 lentil trials. “It was a dry year and we were having a hard time seeing any signs of disease, but there was still that yield advantage that paid.”
Eadie says the application of a fungicide not only provided disease protection for the pulse crops, it also kept the plants living longer, allowing more time for the crop to mature and build yield.
For growers in dry areas who are skeptical of the advantages of a fungicide application, Basaraba recommends leaving a test strip this growing season. Even if a crop looks clean, trial results have shown a foliar fungicide application will almost always make a measurable difference, he says.