If I plan to sow Fusarium-infected seed, when should I use a seed treatment?

Using good quality seed, with high germinability and vigour, and low disease incidence, is always recommended. Cleaning of grain to remove fusarium damaged kernels can improve grade and seed germination. In addition, seed should be planted into warm, well-drained, fertile soil at the appropriate depth. Applying fungicidal seed treatments to cereal seed is also a beneficial management practice that helps reduce risks associated with seedling mortality and reductions in stand establishment due to seed-borne, seed-transmitted and soil-borne fungal pathogens especially when planting conditions are not optimal. Fusarium species are examples of fungi that can cause disease on germinating seeds and seedlings and reduce plant populations. The level of Fusarium infection in a seed lot should be determined by laboratory testing, not just by counting fusarium damaged kernels. In cases where Fusarium infections reduce germination, a germination test should be used to adjust the seeding rate so that emergence and yield are not compromised. Research has shown that when seeding rates are adjusted based on germination rates, seed with low levels of infection (5-10%) have no significant improvement in emergence or yield due to a seed treatment (May et al., 2010). However, it is important to keep in mind that other soil-borne, residue-borne or seed-borne microorganisms (i.e. pests other than Fusarium spp.) can also cause diseases on germinating seeds and seedlings, so even if Fusarium is not detected on seed, a seed treatment should still be considered as a beneficial risk management tool to protect against additional threats such as Pythium spp., Rhizoctonia spp., and others.

Seed treatment recommendations for each province are as follows:

Alberta

Threshold – 0%

Actions/Recommendations – Always use healthy seed with no detectable levels of F. graminearum

Always use a registered fungicidal seed treatment that includes Fusarium on the label

http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex5210

Saskatchewan

Threshold – 2-3%

Actions/Recommendations – Use a seed treatment for F. graminearum infection in areas where F. graminearum is not established

Threshold – 5%

Actions/Recommendations -Do not use seed when F. graminearum infection levels exceed this threshold in areas where F. graminearum is not established

Threshold – 10%

Actions/Recommendations -Use a seed treatment when total Fusarium spp. infection levels exceed this threshold in areas where F. graminearum is established or when F. graminearum levels are less than 5% in areas where F. graminearum is not established

https://www.saskatchewan.ca/business/agriculture-natural-resources-and-industry/agribusiness-farmers-and-ranchers/crops-and-irrigation/crop-protection/disease/fusarium-head-blight

Manitoba

Threshold – none

Actions/Recommendations – Use clean seed with good germination, seed treatments may improve germination

http://www.gov.mb.ca/agriculture/crops/plant-diseases/print,dealing-with-fusarium-head-blight.html#field

REFERENCES

May, W. E., Fernandez, M. R. and Lafond, G. P. 2010. Effect of fungicidal seed treatments on the emergence, development, and grain yield of Fusarium graminearum-infected wheat and barley seed under field conditions. Can. J. Plant Sci. 90: 89 3_904.

Submitted by

Holly Derksen, Field Crop Pathologist

Barbara Ziesman, Provincial Specialist, Plant Disease, Saskatchewan Ministry of Agriculture

Michael Harding, Research Scientist, Plant Pathology, Alberta Agriculture & Forestry

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