Fungicides are integral for preventing disease in many pulse crops, however, just like how weeds have become resistant to certain herbicides, diseases can become resistant to commonly-used fungicide chemistries.
The majority of pulse fungicides on the market in Western Canada contain a Group 11 — the category of fungicide most likely to be overcome by common pulse crop diseases.
“We’ve had Group 11 resistant aschochyta in chickpeas for many years. In the meantime, we’ve also had Group 11 resistant mycosphaerella in peas develop, and most recently, in the last few years, we have seen the introduction of Group 11 resistant anthracnose in lentils,” explains Bethany Wyatt, senior technical service specialist with BASF in west central Saskatchewan.
In many cases, fungicide resistance can go undetected or undiagnosed, she notes, in this Pulse School episode filmed at Ag in Motion near Saskatoon.
“It’s not as black and white or as visual as herbicide resistance. We know that with herbicide resistance, you try to spray the weed, it doesn’t die, it’s still there, and it’s pretty visual. When it comes to fungicide resistance, it’s not that cut and dry. One of the big reasons for that is because diseases in pulses are very patchy in nature. So it also depends on the pressure every year whether it’s actually going to be there, and sometimes it can be very patchy in nature, so it sometimes goes unnoticed quite easily,” says Wyatt.
While BASF has a new pulse fungicide chemistry in its pipeline, it’s important to take a proactive approach to minimize the pressure causing fungicide resistance, she stresses.
“We talk a lot about products and solutions, but we know that we only have limited tools and they only come along so often. So one of the biggest things that we need to be doing is just get back to ground zero, with good integrated pest management. That includes rotation — make sure we’re extending the years of our pulse rotations to help decrease the disease pressure that’s there to begin with,” says Wyatt.
She also reminds growers to rotate fungicide mode of action as much as possible. “It’s definitely not as easy within fungicides as it is herbicides as there are very few options, but really it is utilizing them and trying to rotate as much as possible so that we can extend the life of these products and new actives.”