Grainswest - Spring 2024

Spring 2024 Grains West 22 I t may be thought of as a disease of the past, but ergot still causes headaches for farmers across the Prairies. While its prevalence may be high, its threat level is typically low and often a non-issue. However, the fungus that’s been a fact of life since at least the Middles Ages, remains a concern. Downgrades at the elevator and contaminated screenings cause issues for grain farmers and feedlot owners alike. Simple to identify in a field, the collection of data on ergot occurrences is valuable. Every year, the Canadian Grain Commission’s (CGC) Harvest Sample Program analyzes quality characteristics of samples submitted by farmers from across the country and this includes the presence of grain diseases such as ergot. Sean Walkowiak is keenly aware of ergot developments. A research scientist and program manager for microbiology and grain genomics at the CGC, he sees continued occurrences of the fungal pathogen but doesn’t worry much about it. “There is a trend. It may be increasing in incidence but perhaps not in severity,” he said. “It’s always been on the radar on our Prairies as well as anywhere else grains are grown. This is an issue in other countries.” Farmers who submit to the Harvest Sample Program receive an unofficial grade and all specs related to their grain. Meanwhile, these samples provide CGC with valuable information about the overall quality of Canadian crops. The CGC has collated ergot trend data for the years 1995 through 2020. Analysis of the 230,000 samples collected during that period allowed CGC to rank the occurrence of ergot across the grains. Most affected is open pollinated rye, followed by wheat, durum, barley and then oat. It is also a threat to canary seed. While contamination has always been present, there was a considerable difference in ergot occurrence between the 1995-2009 and 2010-2020 samples. Most notably, ergot presence in rye jumped to 65.6 per cent from 27.6. It also increased substantially to 19.5 per cent from 4.2 in CWRS and to 13.1 per cent from 2.9 in durum. Levels in barley and oat were negligible during this period. In his research, Walkowiak speculates the rise in the presence of ergot could be due to weather variation, germination rates of the disease and overall spore production. He points out, though, that despite increased numbers ergot has consistently posed the same level of median danger. Standards have been developed for acceptable ergot presence domestically and globally (see Table 1). Canadian standards are close to the EU, which has the tightest regulations, regarding acceptable levels. A soilborne pathogen, ergot thrives in wet, cool conditions and can live in the ground for at least one year, possibly longer. The presence of the disease becomes apparent at flowering when an orange-to-yellow substance commonly referred to as honeydew appears on infected florets. Certain insects consume it and inadvertently transfer ergot spores to healthy, neighbouring plants. Ergot honeydew is also spread by rain splash. At the peak of its damage, the pathogen goes on to replace an otherwise healthy kernel with oblong purple-to-black fungal bodies. No commercial fungicides are available to control the disease. Agronomic wisdom typically suggests ergot management include continual mowing of headlands where disease inoculum can often collect, crop rotation that includes a non-cereal option, the use of clean seed and a watchful eye. Because it has often been treated as a minor issue, scientific literature that BY TREVOR BACQUE PHOTOS COURTESY OF CANADIAN GRAIN COMMISSION A DARK PRESENCE Ergot concerns persist in food and feed grains FEATURE