Dry bean growers need a better way to know whether an outbreak of this disease is coming tomorrow, next week or not at all. This four-year research project could provide it.

Most years, sclerotinia white mould is a significant disease issue for dry bean growers in southern Alberta. If the disease takes hold, yield losses of 10% or so can be expected, even with a fungicide application or two.

The 2010 growing season was not like most years. A devastating white mould outbreak caused yield losses of between 50% and 60%.

“White mould is an old foe for dry bean growers and has been a problem for the past 30 years,” explained Syama Chatterton, Lethbridge-based Plant Pathologist with Agriculture and Agri-Food Canada. “When growing dry beans, one starts with a shaky foundation in terms of white mould management. The pathogen is everywhere but most dry bean cultivars have no genetic resistance to white mould and irrigation can help create conditions that favour white mould.”

Focusing on Forecasting

Why is white mould a manageable problem in some years, but a crop-wrecking disaster in others? How can producers know which type of year they’re likely to face?

In 2017, with funding from Alberta Pulse Growers, Chatterton began a four-year project to develop a reliable way to forecast the risk of white mould in dry beans.

“We want to see if we can use airborne spore samples as a kind of advance warning system,” Chatterton said. “The samplers use a little fan that sucks in air and deposits spores in a vial. We bring the vials back to the lab and extract the DNA.”

This analytical process will give Chatterton crucial information on two fronts. First, what is the amount of sclerotinia spores flying around? Second, what is the environmental trigger to release those spores and initiate disease development?

If producers had this information when they need it, it could make their control program more effective. Generally, dry beans are sprayed for white mould at flowering stage and again seven to 10 days later. This approach takes crop staging into account but does not consider the likelihood or severity of white mould occurring.

“For us, 2017 is a proof-of-concept year,” Chatterton said. “We are going to get the spore samplers going and try to determine, does this work and can we get results within an afternoon? We will be out there every two or three days and will also do a weekly disease survey.”

Between now and 2020, Syama Chatterton and her team will build an accurate and timely white mould forecasting system for dry bean.

If this work can help growers manage this disease, and avoid a 2010-style wipeout, that should reduce the risk associated with dry bean production.

“If you knew when the spores would be released, or that disease will occur within the next 24 to 48 hours,” Chatterton said, “that would be very helpful information for producers.”

Project at a glance

Project title:                Forecasting white mould risk in dry bean fields in southern Alberta

Project lead:                Syama Chatterton, Agriculture and Agri-Food Canada

Total value of project: $199,301

Start date:                   2017

Completion date:        2021