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Research developing BMP for clubroot disinfection

Cleaning equipment and vehicles can help to prevent spread.

Disinfecting machinery can help prevent the spread of clubroot. Photo courtesy of Dr. Kelly Turkington, Agriculture and Agri-Food Canada.

It is a dirty job, and unfortunately, many people have to do it. Preventing the spread of clubroot between fields is a time consuming and frustrating job. Yet the stakes are high. Provincial Oilseed Specialist Murray Hartman with Alberta Agriculture and Rural Development (ARD) at Lacombe, Alta., says that clubroot surveys continue to turn up the disease in new locations. “We have confirmed new locations in the counties of Lethbridge and Grande Prairie, and with a much larger survey this summer, we expect to find the disease in more locations,” says Hartman.

One of the ways to stop the spread of clubroot being advocated by oilseed and disease specialists, is to clean equipment when moving from field to field. Clubroot can spread through the movement of spores found in dirt left on farm equipment. Ron Howard, a plant pathology research scientist with ARD at Brooks, Alberta has developed best management practices (BMP) guidelines to disinfect equipment when moving from field to field. “The protocols are based on what we have found in the scientific literature and other published reports from Europe and North America, which we believe will work on clubroot spores,” explains Howard. “It’s based on proven principles.”

A sanitation program for clubroot involves three consecutive steps that increase efficacy at the expense of additional time and labour, says Howard. The appropriate level of cleaning will be determined by the potential for equipment to become contaminated and the risk adversity of the producer.

The first step is to remove soil and plant debris from equipment by scraping or knocking off clumps. Next, residual soil and debris should be cleaned from surfaces by pressure washing, steaming or with compressed air.  Finally, a disinfectant mist, such as a one- to two-percent active ingredient bleach solution, should be sprayed on the clean surfaces to inactivate the spores.   

Howard cautions that cleaning must happen before disinfecting, since dirt deactivates most disinfectants. 

Both Hartman and Howard concede that getting producers to clean their equipment before moving between fields can be a tough sell. Howard says he knows of at least one producer who has decided to set up a system for cleaning his equipment. The farmer first blows off the dirt with high-pressure air. Then, he hoses down the equipment with water using a fire hose connected to an old sprayer pump and tank. Custom machinery operators are bearing the brunt of the cleaning protocols. Essentially, where clubroot is a concern, operators have had to decide if they want to clean equipment or forego revenue. For part-time operators, like farmers with excess machinery capacity, the extra time involved in cleaning can mean giving up on custom activities. 

In addition to the time need to clean equipment, bleach (chlorine) can be corrosive on electronics and metal. That challenge has Howard investigating other alternatives.

New research project to look at better practices
Howard is currently setting up a two-year research project on equipment sanitation that will look at a wide range of practices that could be used to prevent clubroot spread.  He currently has some funding commitments from the oil and gas industry and is lining up other interested collaborators.  

The project will look at several components.  The first is looking at available cleaning technology, such as steam washers and pressure washers to see what works best.  Howard says that the oil and gas industry has some of the best cleaning equipment around, and he will be tapping in to their experience. 

On the disinfectant side, Howard wants to review different products to see if any perform better than bleach, and are more cost effective.  This component will look at both chemical and biological products. He will also be looking at the efficacy of physical cleaning methods, such as steam, hot water and compressed air. “We really need to look at all the alternatives to make sure that we have the best practices in use.  If the industry is going to go through all that effort to clean and disinfect equipment, we need to know that it is worth it,” says Howard.

Hartman says that farm equipment is not the only culprit that can spread clubroot spores.  Any vehicle that carries dirt or mud off the field could spread the spores.  He says some farmers have started posting their land to keep hunters off their fields. 

Oil and gas equipment can also spread the spores, but Hartman says many companies are stepping up and implementing cleaning protocols. “If you are signing new lease agreements with oil and gas companies, make sure that cleaning equipment is included in the lease,” cautions Hartman.  “The good companies, even if it isn’t in the lease, have adopted our protocols for cleaning.”

Howard cites the case of Swift Environmental of Sherwood Park, Alta., as a good example of industry doing the right thing. Swift Environmental has a mobile cleaning operation, which includes setting up a mobile berm that captures cleaning water for disposal.  During the summer of 2008, they set up a cleaning operation east of Lloydminister to clean drilling equipment moving from Alberta to Saskatchewan. 

While farmers have the ability to manage outsider activities on their land, the decision for them to clean or not to clean is tough. It makes sense for a grower to prevent clubroot-contaminated dirt from coming on to his land from other fields or areas that he does not own. Whether it also makes sense for that same grower to clean all of his farm equipment when moving from field to field will come down to an individual’s risk-aversion.