Notes from Clint Jurke, Pathologist with Monsanto at CAAR Crop Forum - this was a pretty good presentation.
This is an important threat to the canola industry. What are we doing to fight this infection?
The 1st discovery of the disease was by Dr Ieuan Evans, now Senior Agri-Coach with Agri-Trend in the 1970’s.
The disease has expanded rapidly from 12 fields in 2003 in Sturgeon County to 2007 where 171 fields we identified in 11 counties…continues to grow…there is a good map on the Alberta web site that is tracking this in some 20 counties. Most is still in the Edmonton area. Now the disease is expanding to Saskatchewan and Manitoba.
Identifcation is easy by watching the root area…swelling of the stem above the roots and then rapid cancer-like division of cells to produce the galls on the roots system.
The infected plants effectively sheds all root tissue and prevents nutrient and water uptake by the plant AND the spores are being released back into the soil. So if you are driving along, just keep your eyes open for drought areas in the field.
Tight rotations, especially in the northern, heavy canola growing areas are contibuting to the spread. This is enhanced by conventional tillage, which moves the spores through the field.
The spores have a 20 year life in the soil and there are millions…brizillions of them…so once you got it..you got it!
While the Edmonton area is susceptible…eastern MB and all of Ontario is very susceptible.
There have been 4 races identified in Alberta.
There was less clubroot in 2009 due to the cool and dry conditions.
Solutions:
Sanitation. Manure will transport the spores.
Management. Longer rotations, liming soils, contolling weeds that are hosts for clubroot…shepards purse, stinkweed, etc.
Resistance. This is likely the only long-term solution to fight this disease. There are many B. napus and B. rapa that have resistance…radish also has many varities with resistance.
The breeding began in 2006 and they began to look world-wide for resistance genes…they found some in Korea. In fact the Koreans, had the reistance genes on the shelves and sent them across to Canada.
The resistance genes were sent to Guelph and testing is now going on in Edmonton, Chile and many other areas.
There has been signifcant progress made in DEKALB hybrids.
Resistance gene will NOT last…only good for 3-4 rotations under single gene resistance.
Growers still need to follow good agronomic practices – longer rotations – scouting – prevention strategies – weed control – tillage systems.
Question – would composting kill the spores? NOT likely.
