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A costly approach to dealing with crop insects and weeds

A head-in-the-sand approach to unfamiliar insects, diseases and weeds simply won't do. Be observant. Early identification and fast action — when required — are best

Jimsonweed got a lot of attention when it was discovered last August in a canola field in Westlock County north of Edmonton.

If Dan Orchard had not discovered clubroot in an Alberta canola field in 2003, we’d all be in ignorant bliss right now. Orchard really should have recognized the scientific principle that if something isn’t “discovered,” then it doesn’t exist and we don’t have to worry about it. He should have left well enough alone, as should those who discovered doughnuts make you fat and that Mars is pretty close and we should go there.

Following the argument so far? No? Well, that’s good because the premise is ridiculous. Of course Orchard was right in sharing his clubroot discovery. Someone else would have made the discovery sooner or later, but earlier is better when it comes to slowing the spread and managing the impact of something so potentially damaging to the economic stability of a crop and an industry.

Orchard’s clubroot discovery started with a phone call from the largest farm operator in the area.

Dan Orchard was the first to identify clubroot in Canadian canola, and recently added Hessian fly to his list of discoveries.
Dan Orchard was the first to identify clubroot in Canadian canola, and recently added Hessian fly to his list of discoveries. photo: Supplied

“He called me to say his field had ripened prematurely and he wasn’t able to properly swath it because plants were pulling out of the ground,” Orchard says. “As an agronomist, I took this an opportunity to get my foot in the door with this big farm, so I quickly responded to his request for a visit.”

The grower said his regular agronomist had already been to the field, and had told the grower it was decaying roots and nothing to worry about. Orchard also expected to find something common, like blackleg or root rot or a nutritional problem.

When Orchard arrived, he found plants laying on top of the ground because the swather just dragged them out instead of cutting them. He found “huge” galls on virtually every plant. “As I pulled the plants that actually stayed in the ground after swathing, they all had fresher galls,” he says. “This triggered my memory.”

Clubroot in canola.
Clubroot in canola. photo: Canola Council of Canada

Four years earlier, while in his final year in agriculture at the University of Alberta, Orchard had done a report on clubroot in canola. “Of course I could only find info from other countries at that time, but based on what I had read for that report, I knew right away this was clubroot.”

Orchard called J.P. Tewari, the university professor and experienced plant pathologist who had assigned the report those four years ago, and said he was bringing some plants for him to diagnose. As Orchard recalls, the prof took one look and said instantly, “If this isn’t clubroot, I’ll eat my desk.” He put samples under the microscope to confirm.

With a positive identification, Orchard called a friend, a more senior agronomist in Alberta, to tour the area with him. Together they found several more fields with clubroot. The friend shared the discovery with the media, which meant the news got out before Orchard had a chance to talk with Alberta Agriculture and the county agriculture fieldman.

“This wasn’t the correct approach in hindsight, but it happened,” he says. And it motivated a lot more field monitoring. “Everyone was shocked with the level of infestation and the ball started rolling from there,” Orchard says.

We know how the story goes from there. Clubroot is now well established in central Alberta and found in many areas of the Prairies. “If I hadn’t found it, someone else would have — although I’d like to think it would’ve been me anyway,” Orchard says. But if the discovery were a couple of years later, it may have caused a more serious setback to canola production in what is and continues to be a highly productive area around Edmonton.

The next big discovery

Other diseases, weeds and insects will come along that require significant and widespread management. Swede midge could be one if it reaches a critical baseline population and conditions become right for an explosion. Glyphosate-resistant weeds are another biggie, given the value of glyphosate to the minimum-tillage program many Prairie growers have adopted. Something entirely unexpected could also come along.

Jimsonweed got a lot of attention in the farm media earlier this fall. Westlock County north of Edmonton reported in late August that the weed had been discovered in canola fields in the county, and soon other counties made similar discoveries. Within a week, jimsonweed made the farm newspapers.

Jimsonweed (Datura stramonium), also known as devil’s trumpet, is one of 21 prohibited noxious weeds on the federal weed seeds order. The Canadian Food Inspection Agency (CFIA) has proposed reclassification from prohibited to primary because the weed is already found in many parts of the country — including in many gardens as an intentionally planted ornamental. All parts of the plant contain alkaloids toxic to humans and animals.

The CFIA continues to investigate how jimsonweed seeds got into these canola fields. Jimsonweed needs hot soils to germinate, which the summer of 2015 provided. Drought-stressed canola was also less competitive, and because jimsonweed tends to emerge late, it probably established after most in-crop herbicide had been applied. It was the “perfect storm” for jimsonweed.

What helped for early identification was that jimsonweed stands very tall and looks unusual, with a large spiky seed pod. Just a few weeds in a field will get noticed. It cannot build up quietly and take hold in a field the way clubroot can.

Will jimsonweed become a major pest in canola? Unlikely. But nature can be hard to predict. If the weed does have staying power, the timely notice by Westlock County to identify and remove jimsonweed before seed set will have gone a long way to reducing any threat this weed may present.

Early detection of unusual weeds, diseases and insects is a good thing. This is another reason why walking fields is so important.

With hundreds of insect species living in Prairie fields, growers and agronomists are bound to find something unusual if they look hard enough. Thankfully most of these are neutral and many of them are beneficial — in that they eat those few insects that are actually pests.

Be observant

If unusual insects are found eating the crop, that’s worth a call to someone.

Scott Hartley, provincial pest insect specialist with the Saskatchewan Ministry of Agriculture, recommends the grower, agronomist or homeowner send samples to the Crop Protection Lab for identification. “If the lab can’t identify it, the lab sends the insect to the National Identification Service in Ottawa or in some cases to other experts depending on the insect.”

The Canadian Food Inspection Agency (CFIA) keeps a list of regulated insects that are non-native to Canada and could be costly. Many of them are tree- and fruit-eating insects, but swede midge and cereal leaf beetle used to be on the CFIA list, Hartley says.

Hessian fly is another non-native insect, and although it came to North America in the late 1700s, it took until just recently to be detected in Alberta wheat. Guess who found it? Dan Orchard.

If Orchard is our Christopher Columbus of clubroot, he’s also the Henry Hudson of Hessian flies. These discoveries have little to do with chance. Orchard walks a lot of fields and keeps his eyes out for the unusual. And when he sees something, he acts — and determinedly so. He reported his Hessian fly suspicion every day for four days before an insect specialist would follow up.

What Orchard’s experiences teach us is this: Look for the unusual. Don’t assume the cause is familiar. Find someone who can identify it. Keep asking around if you have to. Then talk about the risks and work together on an action plan — if an action plan is required. Many of these will be insignificant blips, but management is always easier when a true problem is discovered early.

Jay Whetter is communication manager with the Canola Council of Canada. He is also editor of Canola Watch, a free and timely agronomy newsletter. Sign up at www.canolawatch.org.

This article was originally published as ‘What? Where? I don’t see anything…’ in the November 2015 issue of Country Guide.

About the author

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Jay Whetter is communications manager for the Canola Council of Canada.

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