Last year’s ergot outbreak was caused by weather and not because the variety AC Barrie is susceptible to the disease, say Agriculture Canada researchers Myriam Fernandez and Ron DePauw.
Ergot is an uncommon cereal disease on the Prairies, but last year it struck with a vengeance, downgrading wheat crops across Western Canada.
It’s a fungal disease that usually attacks plant florets before fertilization takes place. Hard compact masses of purplish-black fungal tissue grow in place of the kernel.
These ergot bodies, called sclerotia, are usually a few millimetres in diameter, and may be from 0.2 to five centimetres long.
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Because AC Barrie was the spring wheat variety grown most widely last year, many producers may have been left with the impression this variety is more susceptible to ergot than others. A study of ergot levels in Saskatchewan shows this isn’t true, say the Swift Current research centre scientists.
All varieties affected
Grain samples obtained from several regional variety trials across Saskatchewan were analyzed for ergot levels. The disease was found in many locations, mostly in central and eastern Saskatchewan.
All 16 hard red spring varieties in these trials had ergot levels high enough to cause downgrading in at least one location.
Due to variability in disease development among sites and varieties, no single variety could be identified as more susceptible than the rest.
AC Barrie had a similar reaction as other commonly grown hard red spring varieties, such as Katepwa.
Suitable conditions for ergot development are moisture in the spring and during crop flowering, which is when infections occur. The first cycle of the disease might start with infection of grasses and early-seeded cereal crops. Spores (honeydew) formed on these plants can then infect later-seeded crops.
Any factor that extends the flowering period of cereal crops and grasses, such as wet and cool weather, will increase the opportunity for ergot infection. These conditions were present in most areas of the province last year.
Farmers should remember that ergot bodies developed in 1999 are going to survive for at least a year. If cool moist conditions occur again this year, they shouldn’t plant a cereal crop in fields that had high levels of ergot. They should also make sure to plant ergot-free seed.
Using tillage to bury ergot bodies at least 2.5 cm below the soil will also reduce spore spread the following year.
Wild grasses should be mowed or grazed before flowering to prevent production of ergot spores, removing the bridge for the spread of the disease to cereal crops.
