Grainswest Tech 2021

Tech 2021 grainswest.com 49 BY TAMARA LEIGH Photo:CourtesyofMariaConstanzaFleitas Some farms have reported up to 40 per cent crop loss as a result of BLS. The weather is the biggest influence on the prevalence of BLS in a given year. The bacteria thrive in warm, wet conditions, spreading over short distances through water splash and as plants rub against each other. Large storm systems and wind can carry infected material between fields and into new areas where it can become established if it finds a susceptible host. “You need the pathogen, a susceptible host and the right weather conditions,” said Fleitas. “If you don’t have all three you won’t get the disease; the triangle of the disease has to come together.” Fleitas is working with Randy Kutcher on a project funded by the SaskBarley Development Commission to develop a seed testing protocol to detect pathogenic Xanthimonus translusens on barley seed. The protocol uses colorimetric reaction, a visual detection method that can detect kernels infected with path- ogenic X. translucens that cause disease on cereals from those that cause disease on non-cereal hosts. Also underway is a project to develop a method to test seed- lings and adult plants in the greenhouse or growth cabinet. It is Early symptoms of bacterial leaf streak on wheat include water-soaked streaks (the dark green area) with bacterial ooze that appears as milky droplets. intended to screen commercial cultivars and other germplasm for sources of resistance that breeding programs can use to develop resistant genotypes. They are also working with Harding and other agronomists across the Prairies to determine BLS prevalence and virulence of X. translucens strains isolated from barley samples across Western Canada. This information will indicate the extent of the problem to pathologists, agronomists, breeders and farmers as well as other stakeholders in the cereals value chain. “Right now, scouting and detailed record keeping are the best tools we have to manage BLS,” said Harding. “If you see it, reach out to the people that can help you, like me or your regional seed lab or provincial plant health lab. You don’t want to be using grain from heavily affected fields as a source of seed in 2022, or you’ll be headed for catastrophe. Hopefully, by next season we can have seed lots tested.” Several seed labs are also responding to demand for a seed test. “The prime prevention and key to controlling BLS is going to be seed testing to make sure the seed is free of BLS to avoid bringing it into your field,” said Rachael Melanka, client success manager with 20/20 Seed Labs. “It will also let growers know if their field is at risk for BLS infection and make a decision about whether to use that seed or source new seed. If everything goes well, we expect to have a seed test available next season.” To assist farmers prior to a seed test being made available, 20/20 Seed Labs is promoting a leaf tissue test. “Since there’s no in-crop management, we can confirm BLS on leaf tissue for you,” said Melenka. She added, farmers or agronomists can pick 10 symptomatic leaves, wrap them in a paper towel, put them in a Ziploc bag and drop them off or mail them to the lab. “Our disease diagnosticians can confirm if it’s BLS or if we’re seeing something different. It’s all about collecting the most informa- tion to set you up for success.” While farmers need to be aware of BLS and incorporate mon- itoring and controls into their operations, much work is being done to get ahead of disease before it establishes itself more broadly across the Prairies. If managed right, BLS could remain a relatively rare occurrence. “We don’t want to be taking a disease and continuing it through generations. If we can stop the disease in the field where it is and not propagate infected plants, we can reduce the spread,” said Boychyn. “Right now, scouting and detailed record keeping are the best tools that we have to manage BLS.” —Michael Harding