When Manitoba agronomist Terry Buss goes out on a call from the Beausejour office, he takes a big trunk full of plastic boot covers in the back of the pickup. There are disinfectants in the trunk too, and other cleaning supplies as well, and he uses them all.
Buss has adopted a brand new form of field biosecurity designed to fight the spread of pathogens, so when he’s done his call, his boot covers will get tossed and he will carefully clean his tools before he heads to the next field on his next call.
Buss introduced the system at last winter’s Manitoba Agronomists’ Conference where he was recognized as what you might call the provincial poster boy for biosecurity, and he made some important observations.
“I’ve noticed two things,” Buss said. “One is that the term biosecurity turns people off because they immediately think of extreme stuff like hazmat suits. Getting people to realize that that’s not what we’re really talking about is important. And the other side of it is the ‘it’s not going to happen to me’ mentality. People figure these pathogens aren’t coming to their area, but when they do, then they’ll deal with it.”
Besides, biosecurity also has that unsettling feeling of somehow being linked to bioterrorism. Yet its origins are actually agricultural, with a focus on keeping potential pests and pathogens from multiplying and spreading.
Livestock producers deal with it already. It’s part of their routine vocabulary, and their hygiene protocols for chickens and hogs are proving at keeping diseases out or isolating them within one herd.
Sometimes in the livestock sector, biosecurity even ramps up to the international level, as it did in the early 2000s with the outbreak of foot-and-mouth disease in the U.K. Travellers from Great Britain found themselves walking through trays of disinfectant at the airport to keep them from inadvertently spreading the virus to other countries.
Now, crop farmers here are starting to deal with biosecurity, and the reason is clubroot, a disease of the brassica crops that include cruciferous vegetables and canola. Market gardeners in Ontario and Quebec were already familiar with clubroot but in the mid-1990s it started appearing in Alberta canola fields.
“I work in the county of Leduc, and I’ve been dealing with this since I started my company in 2007,” says Paul Muyres, agronomist with Solid Ground Solutions. “I operate all through Leduc, Wetaskiwin and Ponoka, and I have to manage my biosecurity based on the fact that clubroot is present in that entire area.”
Clubroot presents some intriguing problems. First, we’re not quite sure what it is. Plasmodiaphora brassicae shows characteristics of three distinct types of organisms, including fungi, amoeba and slime moulds, but it doesn’t quite fit into any of those categories.
In the field, a brassica plant would first contact clubroot in its dormant form, an extremely tough resting spore with a potential life of 20 years. If one of these spores touches a brassica root hair, the seeping compounds unique to the plant signal the spore to “wake up.”
This is where the action starts. That tough little spore germinates into a zoospore equipped with two tiny flagella that act like a boat’s propeller, moving it through the film of soil water in search of the root hair that activated it. If the zoospore finds the root hair, it penetrates and infects it and forms a body called a plasmodium that produces and releases more zoospores. These secondary zoospores infect the whole root, so the plant now has a full-blown case of clubroot. The root swells and can no longer absorb water or nutrients. The plant weakens and may die.
Oddly enough, clubroot’s main strength as a survivor is also its weakness. That ultra-tough spore can’t move, so it’s locked in the soil until it’s woken by a suitable root hair. Although it becomes mobile when it germinates, it’s highly vulnerable in its short-lived zoospore state, and it’s very limited in how far it can move.
Agriculture really gave clubroot legs. We work the soil with large machinery, which means infected soil clings in clumps to the bottom of tractors and cultivators as well as the tires. As that machine moves into the next field, the infected dirt falls off and the spores are introduced. The machine becomes a vector.
Since chemical control for clubroot in canola isn’t feasible, the best way to deal with it is to keep clubroot where it is and to prevent it getting any further. But that means we need to be able, as a first step, to find it and identify it.
“There’s a line called the county line between Wetaskiwin and Leduc and for two years there was no clubroot in the county of Wetaskiwin because nobody was looking for it,” Muyres says. “I found it in 2007 but I couldn’t say anything because the farmers there didn’t want us to acknowledge that.”
Denial is merely human, and bad news often trips the reflex to “shoot, shovel and shut up.” Having said that, it’s really important to confirm the presence of a nasty disease like clubroot and make absolutely certain it’s there before going off half cocked. In the larger picture it’s equally important to take a proactive approach by developing ways to contain it, manage it and keep it from spreading. This is really what biosecurity is about.
“Trouble comes on an exponential curve, a mathematical curve that changes very little and very little and then suddenly it takes off,” Buss says. “That’s when my phone rings and that’s when it’s really, really expensive to fix. We need to keep everything back down at the beginning of that curve and that’s a very, very hard thing to get people to understand.”
“We were faced with a problem that we really didn’t have a handle on, so it was kind of the-sky-is-falling scenario,” agrees Muyres. “When I first started, I had an 80-gallon slip tank in my truck and a pressure washer and I had to wash my vehicle all the time, so I was probably washing my truck three hours a day. “I thought, ‘this is ridiculous, I can’t be doing this,’ and that’s when we came up with a checklist and started going through it.”
Buss says the Manitoba government went through something very similar but had the luxury of a later start, so it could look at what other people were doing and what seems reasonable to do. Then they developed protocols, starting with the assumption that every field you go into could have a transmissible problem. From there they came up with a group of procedures that they use all the time on all farms.
“It’s meant using booties, it’s meant procuring and modifying equipment that’s reasonable to clean,” Buss says. “It’s meant looking at alternatives to make it work quickly. We’ve got some basic paperwork that we’ve put together, some sheets where we get signatures from growers depending on what we’re doing, some reporting sheets that we fill out, I do mine on my smartphone digitally every time I go into a field so I’ve instituted some record-keeping.”
All fields that Buss works in are noted and recorded into a database so they’ll be monitored for clubroot and anything else that shows up in the checklist. Although clubroot has certainly brought biosecurity into agronomy, it’s not the only issue we deal with. That checklist has to take the holistic approach to agronomy. The farmer or agronomist who focuses on clubroot may miss something else that’s also important, such as soybean cyst nematode, one of the potential pests that keeps Buss up at night.
“These days I spend most of my time working on soybeans,” Buss says. “There’s a lot of surveying going on down south of us, and the rivers flow our way. I think when we get it (i.e. the nematode) we’re really going to get it because soybeans are such an important crop for us, really the bedrock of all of our crop planning.”
So this is how Buss thinks ahead and how he’s proposing a proactive approach about monitoring and management. We have to look at how these things can get into our fields and then keep looking for them. We have to think of all possible vectors, even the unlikely ones.
Joe Sierens, a farmer and seed dealer also promotes awareness and education, and not just among farmers and agronomists, but anyone who might put something in your field. Knowledge and vigilance have to be the cornerstones of biosecurity.
“I had my own experience. A dealership wanted me to change the colour of my tractor and he brought me a quad track to drive,” Sierens says. “So I get in there and I look and I see 700 hours and that’s a lot of hours on a demo tractor. I asked where this tractor came from, and he said Alberta. I asked, ‘have you ever heard of clubroot?’ and he says, ‘no, what is that?’”
“We need to educate our sales people and machinery sales forces,” Sierens says, “especially in big companies across Western Canada that move equipment on a truck.”