Fusarium head blight (FHB) of wheat, barley, oat, rye and triticale caused by Fusarium graminearum is the most destructive disease of cereals in Western Canada right now.
This fungus is also a destructive disease on corn, particularly in Ontario and the United States, where it is the exact same disease that we have on small cereal grain but it’s called Gibberella zeae. In corn, it’s called stalk rot or on the grain itself ear rot or pink ear rot.
All cereal infections by F. graminearum (Gibberella zeae) produce poisonous toxins (vomitoxins). Pigs and horses are sensitive to less than one part per million (ppm) in grain; whereas, poultry, sheep and cattle are less sensitive. The brewing industry only accepts barley free from vomitoxin and grains for human use must have less than 2 ppm toxin, with many countries worldwide refusing to accept levels of toxin greater than 1 ppm.
In the late 1980s, while employed by Alberta Agriculture as a forensic plant pathologist, I kept hearing about this disease, then called tombstone, causing significant losses in yield and quality, particularly in wheat. It was identified as the same fusarium fungus causing pink ear rot in southern Ontario on corn and causing major feed problems in hog farming.
The first cases
In 1994, this tombstone disease of wheat showed up at Trochu, Alta., brought in on a consignment of Marshall wheat seed from Manitoba. Samples of the original seed showed a 10 per cent seed-borne infection of F. graminearum and in the field that year some 12 per cent of Marshall wheat heads showed infection. Trochu is one of the drier crop areas in Alberta.
Alberta Agriculture personnel sent out warnings to all cereal growers in the province to be very careful about importing disease-carrying seed, wheat and other small cereal grains, with the advice to buy local sources of seed grain.
Over the next few years, stories of extensive fusarium-damaged grain came from Manitoba and the United States. Alberta growers were advised to have seed grains tested for Fusarium graminearum and to be ultra careful of out-of-province sources. Nevertheless, cheap F. graminearum-contaminated grain brought in from out of province had costly and destructive consequences for more than a few Alberta hog operations.
In August of 1999, as Alberta’s forensic plant pathologist, I undertook a survey of small grain cereal crops from Alberta to North Dakota. In the five-day journey, I checked cereal fields in Alberta, Saskatchewan, Manitoba and North Dakota. My first FHB wheat plant was found in a field in Moosomin, Sask., but after that wheat fields in both Manitoba and North Dakota were frequently infested with low to very high levels of FHB. In a field near Fargo, N.D., over 50 per cent of the wheat had FHB infection.
Alberta Fusarium Graminearum Management Plan
With lots of help and lots of discussion, I was able to essentially launch the Alberta Fusarium Graminearum Management Plan. Over the next 15 years, this FHB management plan saved Alberta cereal growers not millions but billions of dollars. At the same time, cereal growers in both Manitoba and Saskatchewan lost billions of dollars in disease-ruined grain harvests and downgraded fusarium-contaminated grain.
Alberta growers, in fact, captured the lion’s share of malting barley sales. In the early part of this century, a few years back, very little in the way of malting barley was available outside of Alberta.
“The Alberta Fusarium graminearum plan was a failure.” I could not believe this statement coming from growers and officials in the southern irrigation areas of Alberta. All the individuals calling this program a failure must have heavily spotted tongues.
Up to recent times, the program was a total and unqualified rip-roaring success. The savings of billions of dollars to Alberta’s grain growers a failure? Who were these southern growers listening to?
FHB-damaged grain as cattle feed
A major reason why the irrigation wheat growers in southern Alberta were experiencing significant losses from FHB was the fact that large quantities of FHB-damaged grains were imported from Manitoba and Saskatchewan as cattle feed. Can you guess how much FHB-infested grain spilled into the feed lot manure? These FHB-contaminated manures were spread onto surrounding cropland — huge loads of FHB fungus inoculum.
While FHB was common amongst grain growers, it also affected southern Alberta seed growers who were unable to produce FHB-free grain as required by the provincial FHB program.
On the other hand, north of Calgary, the FHB program worked exceptionally well up to the present time. Unlike grain fields in Manitoba and Saskatchewan, where it was not uncommon for me to see FHB infestation levels of 10 to 40 per cent. I seldom, if ever, found even trace levels of FHB as recently as 2020 in the Edmonton area.
So, why was the FHB program dropped?
There were lots of complaints and delegations from southern Alberta to halt the program, which indeed was a genuine problem in their specific areas. The government of Alberta could well have split the program into separate administration areas, but that option was dropped. In the meantime, the FHB infestation levels have progressed significantly in the south and east-central areas of the province. It was impossible to produce FHB-free seed grain in those areas, making the zero tolerance for FHB-free seed untenable.
Even if the Alberta Agriculture FHB program is now scrapped, cereal seed growers in these and all regions should continue as usual and grow as clean a seed as they can purchase, follow a rotation, treat seed, test seed for toxins, seed heavily and use fungicides if necessary.
In conclusion, all I can say is that prevention programs can and do succeed, such as keeping Alberta rat-free and free of Dutch elm disease for the million or so elms in the province.
While some growers in Alberta are happy the program was dropped, an equal or likely a much bigger number are displeased this program was terminated.
Do not let naysayers and malcontents ever say that this FHB program should never have happened. In reality, it was nothing short of a resounding financial and unqualified overall success that put much-needed money in the pockets of Alberta grain growers. Control programs with stakeholders in all of Western Canada could work very well and should be employed when and where feasible for any crop pest problem.