Healthy pulse crops demand good disease management

The 2016 growing season is one many pulse growers in Saskatchewan would rather forget. It was one of the worst seasons for disease in recent memory. Some diseases took down yield while others, such as white and grey mould, had a big impact on quality. But with a new year and a new season ahead, there are still reasons to be optimistic.

“Last year was like nothing we’ve ever seen,” says Troy LaForge, head agronomist with Ultimate Yield Management Institute in Saskatoon. “In some areas, threequarters of the field had such high levels of disease damage that there was nothing to harvest,” he says. “We knew at some point the perfect storm of tight rotations and weather would combine and last year it happened.”

With that in mind, this year, many producers are changing management systems. Heading into the 2017 season, pulse growers are being more proactive in their approach to disease management, says LaForge. Crop rotation can be problematic in many pulse regions as tight rotations are common and many rotational crops are susceptible to the same diseases that attack pulses. But increasingly, he says, where growers can rotate, they do. And they are prepared to spray.

“It really is a matter of being proactive,” says Marilyn Kot, an agronomist with Green Acres Tech Inc. in southeast Saskatchewan. “If you are going to grow pulse crops in this part of the world you have to be prepared to manage for disease, and that means timely use of fungicides,” she says. “And as long as you stay on top of the disease you can be very successful.”

Keeping chickpeas clean

Ascochyta blight is the nemesis of chickpea growers. The disease can make an otherwise good looking crop look bad, and perform even worse. Fifteen years ago, growers struggled with ascochyta as it developed resistance to strobilurin fungicides. Today there are different fungicide chemistries available to better manage this disease. »

“The key is to not let disease get ahead of the crop,” says LaForge. “There are varieties with some level of resistance, and, combined with a seed treatment, can help start a healthy crop that is less susceptible to disease,” he explains. “But all that is not enough if you are not using a foliar fungicide program to control disease incrop.”

Kot agrees and says: “Chickpea growers know they are going to get ascochyta so it’s no longer a question of if they are going to apply a fungicide, it’s a matter of when. The first application is the toughest call as you want to wait as long as you can. Then, depending on the nature of the disease, you will need to apply every 10 to 14 days until that crop reaches maturity.”

Taking on disease in lentils

Ascochyta is also problematic in lentils. “Even a few years ago you could get away with not spraying depending on the season,” says Kot. “But now it is everywhere. Last year I scouted in fields of first time lentil growers and even they had ascochyta.”

Anthracnose can also be an issue in lentil crops, but it doesn’t show up every year and requires wet, cold summers to flourish. The good news is that most fungicides that are used for other diseases in pulses can easily manage this disease.

What caught some pulse growers off guard last year were sclerotinia and botrytis. These white and grey moulds show up later in the season once the canopy is heavy and moist — ripe conditions for disease development. Both diseases move quickly through the canopy. Kot says decisions on how to best manage these diseases should be made on a field-by-field basis, before there are visible signs of the disease.

“The challenge with managing sclerotinia and botrytis is getting the fungicide into the canopy,” she says. “You need to make sure you have the appropriate nozzle on your sprayer and lots of water to make sure you get deep into that canopy. Sometimes you can prevent damage, and sometimes you are just protecting what you already have.”

In addition to fungicides there are some other methods to help manage for disease such as planting wider rows to allow more air to get down through the crop to help prevent the disease from flourishing and using biological products to help control the spread of disease.

“Our research division is looking into better managing pulse production and we’ve seen a statistically significant difference when you combine balanced fertility, low stress herbicide combinations and fungicides to better manage for disease,” says LaForge. “When it comes to all disease in pulses, a timely, multipronged approach helps set up the crop to be more successful at fighting off disease for better quality and bigger yields.”