Infection severe | Fusarium affects up to 60 percent of kernels in some areas
Fusarium head blight is causing headaches for western Canadian farmers and pedigreed seed growers.
The problem is particularly severe in Saskatchewan, where the disease was widespread in 2012 and infection levels were higher than ever in many crop districts.
Unusually high levels of fusarium damaged kernels in some regions are fuelling concerns about commercial and pedigreed supplies of spring wheat, durum and barley.
Maximum thresholds for fusarium damaged kernels (FDK) in commercial spring wheat crops are 0.25 percent for No. 1 Canada Western red spring, 0.8 percent for No. 2 and 1.5 percent for No. 3 and 4.
Fusarium graminearum, the most toxic type of fusarium, affected 30 to 60 percent of kernels in durum and spring wheat samples in some areas.
“Fusarium was pretty widespread this year compared to other years,” said Daryl Beswitherick, program manager of quality assurance services at the Canadian Grain Commission.
FDK levels in commercial wheat crops came in at 0.5 percent or less in most parts of Western Canada, he said.
However, levels were much higher in some areas of Saskatchewan, often five percent or higher.
“That (five percent) is a significant amount so they’re going to have some issues moving that grain, I would think,” Beswitherick said.
Markets are limited for grain with high levels of FDK.
Fusarium infected crops can be cleaned to remove shrunken kernels or blended with supplies of higher quality grain.
However, cleaning costs can be prohibitive and the amount of wheat with high levels of FDK was significant in some areas, meaning local blending opportunities could be limited.
Cereal crops infected by fusarium head blight contain mycotoxins that can severely limit the value of the grain among millers, bakers, maltsters, livestock feeders and biofuel manufacturers.
Deoxynivalenol (DON), the most common mycotoxin, is produced in large amounts by fusarium graminearum. It reduces feed intake by pigs and cattle and adversely affects the milling, baking, processing and malting properties of grain.
Ethanol producers are also reluctant to use infected crops because DON levels become more concentrated in dried distillers grains, a grain-based byproduct of ethanol production that is commonly used in livestock feed rations.
Fusarium is becoming more prevalent in Saskatchewan and Alberta, but Beswitherick said it didn’t affect all producers.
Western Canadian wheat growers harvested a high quality spring wheat crop last year, with 73 percent of CWRS production falling into the top two grades — 13 to 14 million tonnes.
That high quality crop will present opportunities for grain handling companies to blend low-quality grain.
“You’ve got a lot of product to be able to blend with, so the handling system can absorb some of that (fusarium damaged material),” he said.
Pedigreed seed producers are facing similar problems.
Fusarium damaged kernels in pedigreed seed lots were well above five percent in some areas and clean-out losses were significant, sometimes above 35 percent.
David Gehl, head of the seed increase unit at Agriculture Canada’s research farm near Indian Head, Sask., said fusarium was rampant in the farm’s breeder seed plots last year.
The level of infection in some breeder seed plots was higher than levels recorded in inoculated fusarium research nurseries in Manitoba, said Agriculture Canada plant breeder Ron DePauw.
Surveys of the most susceptible varieties of spring wheat and durum at Indian Head indicated severe fusarium head blight infection on 50 percent of heads.
Subsequent laboratory tests on grain harvested from the same plots showed 83 to 100 percent fusarium graminearum infection rates.
“It was a pretty ugly situation, really,” said Gehl.
“In some of our plots, I estimated that we had yield losses of 45 percent on some of the most susceptible varieties.”
Elevated fusarium levels in breeder seed could have a costly and far-reaching effect on the pedigreed seed industry.
The seed increase unit at Indian Head supplies breeder seed to pedigreed seed growers in Western Canada for further multiplication and eventual distribution to commercial growers.
Fusarium graminearum is a regulated disease in Alberta, and the province’s management plan has a zero tolerance policy for the disease.
That means breeder seed with any trace of the pathogen will not be allowed into the province unless thresholds prescribed by the management plan are adjusted.
“That’s a big concern for us, is to be able to supply breeder seed of our new varieties to (pedigreed seed) growers in Alberta,” Gehl said.
“It’s been a fairly ugly situation, to be honest with you.”
Gehl said there is a chance that breeder seed from Indian Head can be cleaned and disinfected to meet Alberta’s zero percent threshold.
Unlike most pedigreed seed growers, Agriculture Canada has access to a dry heat procedure that is capable of killing the fusarium graminearum pathogen on seed.
However, Gehl said it is still unclear if the process will be effective.
If not, an entire generation of seed could be lost, at least for pedigreed seed growers in Alberta.
“We’ll still have to see whether that’s going to be effective under these heavy infestation levels, whether we can get it down to no detectable fusarium,” he said.
“We’ll find out in the new year.”
Either way, supplies of breeder seed will be scarce because of reduced yields and high clean-out losses.
Pedigreed seed growers are facing similar concerns in other parts of Saskatchewan.
Bruce Carrier, owner of Discovery Seed Labs, said pedigreed seed growers in some areas may be forced to sell pedigreed wheat and barley supplies into commercial milling markets or as feed.
“Seed samples, depending on the area of the province you are in, are up to a point where … the majority of it is not usable for seed,” Carriere said.
“There’s going to be a seed shortage, big time.”
Crop districts 8A and 8B in northeastern Saskatchewan were particularly hard hit, but severe infestations were also recorded in other parts of the province, including Yorkton, Assiniboia, Saskatoon and North Battleford.
The pedigreed seed industry does not have a threshold for FDK in certified wheat and barley seed, but pedigreed seed growers are concerned about the risks posed by seed-borne fusarium that cannot be seen with the naked eye.
Carriere said pedigreed wheat seed with FDK levels of five to 10 percent can usually be cleaned to a point where the seed is usable.
Efforts to clean pedigreed barley supplies are less successful.
Regardless of cleaning efforts, pedigreed supplies of wheat, barley and oats will be in extremely short supply.