Root rots are the number one disease issue for pulse crops, significantly impacting pea and lentil fields across the Prairies. Studies show that the disease which thrives in warm, wet conditions can cause a yield loss of anywhere from 60 to 84 percent.
Last year, the Saskatchewan Ministry of Agriculture conducted a pulse disease survey, which focused on the root rot disease complex.
Mike Brown, an agronomy specialist with Saskatchewan Pulse Growers, says the survey focused on 55 lentil fields and 40 pea fields with ten plants being pulled at five different locations throughout each field.
"So there were 50 plants per field that were checked on average. Here with the lentils, 21 of the 50 plants looked at per field showed signs of root rot. When we look at the severity side of things, our severity is rated on a one to seven scale. One's gonna be no root rot the plant's healthy, seven you're basically looking at a dead plant there. Overall, when we look at the severity, it was relatively low. We did have the worst symptoms in the south areas of the province."
The survey found that 36 of the 40 pea fields examined showed signs of root rot, with a slightly higher severity rating of 2.2 out of 7; with the west-central region having a severity rating of 2.3, while the southwest region was at 2.6.
He says as a result they can basically determine the odds that we would see a problem in a pea, lentil or dry bean field somewhere in the province.
"Pick out a single plant and what are the odds that plant is going to show signs of root rot based on the results from the survey numbers we saw last year. Dry bean odds were pretty low, but lentils were looking at one in three, and peas were a coin toss your looking at 50/50. So, your odds are pretty good on running into a plant that's going to have root rot in a pea or lentil crop."
The current recommendation is to avoid growing peas or lentils in fields with aphanomyces for at least six to eight years to mitigate the risk of root rot.