CANOLA DISEASE PACKAGING – WHAT TO PLAN FOR

Blackleg, sclerotinia and clubroot are growing concerns for canola producers in Western Canada. Provincial disease surveys in Alberta, Saskatchewan and Manitoba show the incidence and spread of blackleg and sclerotinia have been trending upwards in recent years, while clubroot continues to push eastwards out of Alberta and into northwestern Saskatchewan. Recently, there have also been a few confirmed cases of clubroot in Manitoba.

 

Like many things in life, prevention can be much more cost effective than trying to manage a disease once it’s established in the field. Canola growers are wise to use preventative tactics when they can to keep pathogens like blackleg, sclerotinia, and clubroot from appearing in their fields.

 

BENEFIT FROM BUILT-IN DISEASE RESISTANCE

 

One strategy a producer can utilize in managing blackleg is to plant canola with genetic resistance. This tool needs to be used in conjunction with other management practices such as crop rotation to remain an effective tool into the future. Currently, there are Genuity® Roundup Ready® canola hybrids available to producers that offer genetic resistance to blackleg and clubroot pathogens, as well as tolerance to sclerontinia. While they’re not a silver bullet solution for yield-robbing pathogens, diseaseresistant canola hybrids can be a great disease management tool.

 

Blackleg resistance, which has been available in commercial canola varieties since the 1990s, is currently determined by a rating system that compares the field resistance of new canola hybrids with the highly susceptible variety Westar. The four ratings are: R for resistant, MR for moderately resistant, MS for moderately susceptible and S for susceptible.

 

MAJOR GENE RESISTANCE LABELS ON THE HORIZON

 

In the coming years, new blackleg resistance labels will be added to canola cultivars that provide more details on a variety’s resistance package for blackleg management. This new, major gene resistance label will be an important step forward in ag industry transparency – letting growers know which blackleg resistant genes are in the canola they’re buying. Armed with this knowledge, growers will then be able to rotate resistance genes within their fields.

 

Growing the same disease-resistant canola hybrid repeatedly on the same field year after year will select blackleg races that can overcome genetic resistance in that hybrid and increase disease severity. Rotating hybrids, or more specifically rotating the resistance genes, creates the opportunity to bring a mix of resistance genes to the field over time, which reduces selection pressure and improves the durability of that resistance trait

 

BEST PRACTICES FOR DISEASE MANAGEMENT

 

Growers shouldn’t solely rely on canola hybrids with genetic disease resistance to combat plant pathogens. Some disease management practices I’d recommend are:

  • Implement a rotation that includes at least four different crops. This will reduce the amount of disease inoculum present in the field and will also preserve the effectiveness of disease-resistant canola hybrids for longer.

     

  • Utilize treated seed. A good seed treatment will protect your crop from multiple seed-borne diseases. Foliar fungicides can also be a very useful tool in high disease-pressure situations.

     

  • Control weeds and volunteers. Canola volunteers and related weed species like wild mustard can host canola diseases in noncanola years. Controlling these in non-canola years is crucial to breaking the disease cycle.

 

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