Growers urged to scout fields for black leg
Pacific Northwest farmers should scout their winter canola, brassica and crucifer crops for black leg fungus.
“Industry concern is still at a heightened level,” said Victor Shaul, seed program manager with the Washington State Department of Agriculture.
Black leg was found in Oregon and Idaho, but not yet in Washington, which has a crucifer quarantine and accepts only seed certified as black leg-free.
Black leg affects brassica and crucifer crops, including spring and winter canola, rapeseed, mustard, broccoli, cabbage, cauliflower, kale, bok choy, Brussels sprouts, turnips and tillage radish.
Also a concern is volunteer canola or mustard. Reports of volunteer canola in fields and ditches are up over past years, said Karen Sowers, an oilseed cropping systems research associate with Washington State University.
Spring canola is being planted, but farmers will want to check their fields shortly, Sowers said.
Fungicides won’t help existing black leg, Sowers said, but will prevent it from spreading.
WSU, University of Idaho and Oregon State University researchers are available to answer grower questions or test possible instances of black leg, Sowers said.
OSU recently held a workshop to train people to spot black leg symptoms in canola. Symptoms first appeared on trials in February, which means they were infected at some point last fall, OSU extension soil scientist Don Wysocki said
Black leg could have been around a while before people started noticing it, Wysocki said.
“That suggests to me it hasn’t been a big bust on yield — we would have noticed huge yield losses, and we haven’t seen that,” he said. “We’ve had it, but maybe it’s a tolerable level.”
Wysocki would like to research fungicide treatments, to determine if a preventive fall or spring treatment would prevent the infection, including the costs and benefits.
“How much more seed would you get by putting on a fungicide at those times?” he said. “Those are questions we can’t answer at this time.”
Sowers recommends awareness.
“It’s not a fear factor at all,” she said. “It’s a treatable thing, but we need to keep it under control so it doesn’t get to Washington state.”
A WSDA public meeting in Yakima, Wash., on the crucifer quarantine, slated for May 12, was postponed. Researchers expressed concern over language proposing variety trial ground be isolated from crucifer production, said Shaul, the WSDA seed program manager.
“Certain trials need to be in a production field so it’s treated just like commercial canola would be,” he said. “Having that requirement kind of negates the point of having a trial.”
Introducing black leg through trials is not a concern, Shaul said.
Sowers recommends a four-year crop rotation between brassica or crucifer crops and planting only seed certified as free of black leg.
Shaul asked industry members to alert the department if they find a seed lot that isn’t certified.
“At this point, we’re strictly at an educational level working with seed suppliers,” he said. “As we encounter companies that may not be aware of the quarantine, we’re working with them so they understand our rules.”