Root rot has long been a thorn in the side of pea and lentil farmers, but the 2024 growing season brought a surprising twist. Despite heavy rainfall during May and June — typically a recipe for elevated root rot risk — the severity of the disease was lower than expected. This has sparked optimism and underscored the importance of one time-tested farming practice: crop rotation.
Root rot is caused by a complex mix of fungal and fungus-like organisms, but other factors also play a role. Abiotic conditions, such as flooding and soil oxygen depletion, can contribute to root rot by causing root cell death and producing symptoms that resemble the disease. These conditions also create an environment that makes it easier for root rot pathogens to infect plants.
“We saw root rot in about 80 to 90% of all pea and lentil fields, but the severity wasn’t as high as we’ve seen in previous years. It’s possible that producers are listening to recommendations to extend their crop rotations beyond the typical three-year break,” says Syama Chatterton, an Agriculture and Agri-food Canada pulse crop pathologist specializing in root rot.
Producers who spaced pea and lentil crops further apart in their rotations appear to have reaped the rewards in 2024. Fields that had been planted with peas or lentils in 2018 or 2019 and left until 2024 for another pulse crop saw significantly reduced root rot prevalence compared to fields with shorter rotation intervals.
“It’s the old wisdom of rotations,” Chatterton says. “Spacing crops out is still the most effective tool we have against root rot diseases. It’s clear that extended rotations are paying off.”
However, weather remains a wild card. Wet years like 2024 amplify root rot risk, especially in fields with a history of consecutive pulse crops in wet seasons. “Some fields were heavily hit by root rot, particularly those that had pea or lentil crops in 2016, 2020, and 2024 — all historically wet years,” she says.
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