OSCIA: Disease awareness can improve alfalfa yield, quality

Traditional diseases affecting alfalfa crops are as prevalent as emerging ones — that’s the somewhat surprising finding of the 2012 alfalfa disease survey that was conducted in Ontario last year to look at incidence, distribution and severity of many common diseases affecting commercial alfalfa fields in Ontario.

“We were initially thinking we would find mostly new diseases and we did, but at relatively low levels,” says pathologist Albert Tenuta, field crops program lead with the Ontario Ministry of Agriculture and Food at Ridgetown. “We found the older diseases to be quite prominent, ones that we haven’t been paying as much attention to and that have gone under the radar as endemic issues in production.”

How was the research conducted?

Researchers surveyed 18 alfalfa fields across southern Ontario using traditional field sampling, processing and mycological culturing to determine the distribution of fungal diseases in fields with typical alfalfa yellowing symptoms. They also tested new molecular technologies for crop disease identification, developed by Andre Levesque at Agriculture and Agri-Food Canada in Ottawa, to evaluate their suitability for forage crops.

What has the project found to date?

Emerging alfalfa diseases include aphanomyces root rot (race 2) and brown root rot, and although the survey found these in Ontario, Tenuta says older, more established diseases were present in unexpectedly high numbers. In particular, a large number of fusarium species were found in more than half the samples taken, which could indicate potential changes in fusarium diversity in the province.

“Many of these older diseases can have a real negative impact on root health, forage quality and productivity,” he explains. “We’ve made great progress in developing new varieties, but we have to also remember that some of those older challenges are still there. What we’re seeing here is ‘what is old is new again.'”

The presence of aphanomyces root rot (race 2) in the province was confirmed using a new greenhouse differential test and Tenuta says the diagnostic capacity of these new molecular identification tools will allow for earlier detection, quicker sampling of grower fields and plant samples, and help breeders identify new lines with potential resistance. Although alfalfa was used as the first commodity-based study of this new technology, it could be applied to other crops as well. As a result of its success in alfalfa, AAFC Ottawa will be looking at other crops like cereals in 2013.

One farmer who knows the value of good quality forage to his growing hay business is John Schaer. He grows 150 acres of forage crops, including alfalfa, on his farm near Hanover in southern Grey County.

“There is definitely an increasing demand for good quality hay,” says John. “If you are going to grow a good crop, it’s important to know what diseases are out there that might affect your quality so that you can get the best return.”

Forage is already a significant part of Canada’s agricultural economy. According to the Ontario Forage Council, it was the third largest crop in terms of income generated at the farm level in 2011 and supported $50 billion in direct and indirect economy activity across the country.

Where can I get more information? More information on this project can be found in Crop Advances online.

How was the research funded? Funding for this project was provided by Growing Forward, a federal-provincial-territorial initiative. The Agricultural Adaptation Council assists in the delivery of several Growing Forward programs in Ontario. OSCIA assisted with communication of research results.

— Lilian Schaer is a freelance writer and communications project specialist at Guelph, writing on behalf of the Ontario Soil and Crop Improvement Association (OSCIA).

Key project tips

  • Be vigilant. Monitor your crop and be aware of what’s happening in your fields.
  • Take action. If you notice something unusual, dig up a few plants and look at the roots – there are many things below ground that can affect productivity of your alfalfa crop.
  • Select appropriate varieties. Look at the specific conditions in your area and pick varieties that are suited that environment.

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