Skip to main content
APS Plant Health 2025 Main banner
Icon Legend
This session is not in your schedule.
This session is in your schedule. Click again to remove it.
ViewAttendees 2

POSTERS: Oomycetes II

P-486 - Prevalence and Management of Phytophthora sojae in Manitoba, Canada Soybean Fields

Tuesday, August 5, 2025
10:15 AM - 11:00 AM HST
Location: Exhibit Hall 3

    Presenting Author(s)

  • YK

    Yong Min Kim, PhD (he/him/his)

    Research Scientist
    Agriculture and Agri-Food Canada
    Brandon, Manitoba, Canada

    • Author(s)

  • AA

    Ahmed Abdelmagid

    Research Scientist
    Agriculture and Agri-Food Canada
    Morden, Manitoba, Canada

  • OW

    Owen Wally

    Research Scientist
    Agriculture and Agri-Food Canada
    Harrow, Ontario, Canada

Abstract Text: In 2024, Manitoba’s soybean seeded area reached 1.43 million acres, an 8% increase over the five-year average of 1.32 million acres, making it the second-largest soybean-producing province in Canada. Phytophthora stem and root rot, caused by Phytophthora sojae, was first reported in Manitoba in 2011 and has since become a significant threat to soybean production. This soil-borne pathogen can infect soybeans at all growth stages, with the deployment of Rps resistance genes remaining the most effective management strategy. To assess the prevalence and pathotype diversity of P. sojae, a survey of 62 commercial soybean fields was conducted in 2024. Plant and soil samples were collected, and approximately 105 stems were plated on modified 3P lima bean and diluted V8 selective media. Phytophthora sojae was isolated from 15% (9/62) of surveyed fields based on morphological characteristics, with identity confirmation through ITS region sequencing. Plant samples were also tested using Agdia ImmunoStrip as a rapid diagnostic tool. Additionally, molecular detection using droplet digital PCR was performed on root and soil DNA to evaluate P. sojae prevalence. Pathotyping of P. sojae was conducted using molecular pathotyping from root and soil DNA, soil baiting, and stem plating. Understanding pathogen genetics and population dynamics will provide valuable insights for soybean producers in Manitoba, enabling informed decisions on disease risk management and the selection of appropriate Rps genes for resistance.