This Canola School episode focuses on testing for clubroot and how to go about determining whether clubroot spores are present in the soil.
Finding the nasty soil-borne disease when spore loads are still low allows a grower to manage the disease to avoid high concentrations seen in central Alberta, explains Angela Brackenreed, agronomy specialist for Manitoba with the Canola Council of Canada.
She describes the guidelines for collecting a soil sample for clubroot (see sampling steps below), noting it can be collected at any time of year.
“You want to start by going into the approach that is most commonly we used. We find most producers turn to the right, and so the highest concentration of clubroot spores tend to be at the approach and to the right, so that’s where we’d encourage you to start,” explains Brackenreed.
The Pest Surveillance Initiative Lab in Winnipeg, a partnership between the Manitoba Canola Growers Association and Manitoba Agriculture, is testing soil from every township-range in the province for clubroot disease. The PSI lab is one option for growers looking to have their own test done. As Brackenreed notes, under Growing Forward 2, a producer might be eligible for a rebate on the PSI’s $125 fee if their township-range has not yet been tested.
Soil samples can be collected at any time but soil should be dried after collection. Do not drive into field or access, but park on the road whenever possible. Follow sanitation procedures if visiting more than one field. Dispose of or clean and disinfest footwear and tools that come in contact with the soil.
Soil Sample Survey Procedure:
1. Soil samples should be a composite of five, one cup scoops of soil taken at each of five stops in one field. As clubroot concentration have been found to be the highest at field approaches in infected fields, the samples should be taken within the vicinity of where equipment would usually enter into the field. Travelling in a “W” pattern, stop at the five points of the “W” keeping each of these five points at least 20 metres from each other and at least 20 metres from the field edge.
2. Clear away residue from the soil surface, and scoop approximately one cup of the top zero to 10 cm of soil at each site (total one litre from all five sites combined).
3. Air-dry soil samples in paper boxes and send them to a lab for DNA testing.