The clubroot tour has hit Central Alberta.
On Aug. 19, nearly 100 producers, industry professionals, and agriculture service providers were given a tour of a Red Deer County canola field known to be infested with clubroot, and planted by the Canola Council of Canada for demonstration purposes.
“This is the best time to look for clubroot infestations,” said Murray Hartman, oilseed specialist for Agriculture and Rural Development Alberta. “You can't tell when you plant your crop, or within the first three weeks. It has to be when the crop has started maturing.”
The plot of canola located south and west of Penhold on Rge. Rd. 10 was planted with clubroot resistant and non–clubroot resistant seed intermittently.
“Earlier in the season you could not tell which was which,” said Keith Gabert, agronomist with the Canola Council of Canada. “But now, as the galls have grown on the canola plant roots and it is later in the season, you can see which have not received adequate nutrition.”
Participants were encouraged to pull up canola plants and look at the roots. The differences between infested and non-infested plants were obvious.
“Infected plants have galls on the roots, and can be quite gnarled.The worse the infestations, the larger the root, and the less moisture and nutrition they can draw from the soil,” said Hartman, pointing out the difference between infected and clean plants. “If you look at the stem above the ground in infected plants, they are thicker and the leaves/stems at the top of the plant are thinner. Canola like this can be harvested, but it does yield less and hurt producers in the pocketbook.”
Scientists and researchers from the University of Alberta gave short presentations on current research into clubroot with a bent towards strategies for prevention of infestations and provided information on the variety of clubroot present provincewide.
Dan Orchard, a Wetaskiwin agronomy specialist, spoke on being the man who first “discovered” clubroot in Alberta canola fields in 2003, noting that if he knew “what I was looking for, I could have found it in 1993.”
“Once we knew that clubroot could spread into canola, we started looking at clubroot-resistant varieties for use in Alberta,” said Orchard. “It does spread quickly, and even resistant strains can have up to five or 10 per cent infection before damaging the plant. It is very important to not let the inoculum spread in the soil.”
Hartman added that the best strategy to prevent clubroot is likely to refrain from using resistant strains in crop rotation on the same field every year, but rather rotate every four years.
“Ideally, we would like to have multiple options for seed that are resistant to the varieties of clubroot that can be rotated into a field,” said Hartman. “It would be helpful if the seed industry were to label their product with which strains the seed is resistant to.”
He noted that the two present strains of clubroot are behaving the same under testing in research and in-field -- the crops are not yielding fully in as little as two years once the resistant strain is introduced.
“We need to continue research into the varieties of clubroot, and to have options available,” added Hartman.
Dr. Stelkov of the University of Alberta noted that clubroot could spread to plants other than canola and that the billions of spores produced from the galls can decimate a crop in a small number of years.
“It takes as few as 100,000 spores to produce visible results on roots yet each gall produces as many as eight billion spores,” said Stelkov. “If we can reduce the number of spores we can reduce the effects of infestation.”
The scientists pulled a stinkweed out of the adjacent wheat crop and showed the galls on the root.
“Even weeds can spread clubroot,” said Stelkov. “We have to be diligent and make sure that we prevent its spread as much as we can.”
Hartman was quick to point out that seed rotation strategies were not “a silver bullet” but only part of the solution.
“If you can see clubroot in the field across the road, it's probably time to plant a resistant variety,” said Hartman. “But, in fact, it might even be too late.”
A demonstration of equipment cleaning followed the field demonstration and focused on rough cleaning, fine cleaning, and sterilization of tillers that would reduce the concentration of clubroot on field entrances.
Information on clubroot can be found at www.rdcounty.ca or at canola.ab.ca.
