Last week the Saskatchewan Ministry of Agriculture released results from an extensive survey they conducted focusing on root rot diseases in pulse crops, particularly lentils and field peas. The findings highlight the prevalence and severity of root rot, offering valuable insights for pulse growers in Montana who face similar challenges.
Survey Findings:
● Lentils: Root rot symptoms were observed in 85% of surveyed fields, with an average incidence of 41% and a severity rating of 1.7 on a 1–7 scale.
● Field Peas: Root rot was present in 90% of surveyed fields, averaging a 57% incidence and a severity rating of 2.2.
The root rot complex primarily involves pathogens such as Aphanomyces euteiches, Fusarium spp., Pythium spp., and Rhizoctonia solani.
According to Dr. Uta McKelvy, Montana State University Assistant Professor Extension Plant Pathology pathogens attack at different stages in crop development. “Rhizoctonia and Pythium tend to be early-season pathogens, preferring colder and wet soils, and are more likely to cause seed- and seedling diseases,” said Dr. McKelvy. “Fusarium spp. and Aphanomyces prefer warmer soils. Aphanomyces thrives in heavy, wet soils. Fusarium thrives on stressed plants, e.g. drought stress, soil compaction, or herbicide injury.”
Dr. McKelvy added: “Aphanomyces is particularly tricky, because it produces long-lived oospores that can persist in the soil for a decade or longer.”
Relevance to Montana Growers:
Montana’s pulse growers operate in environments that can mirror Saskatchewan’s conditions, making these findings pertinent. Understanding the prevalence of root rot and its contributing factors can aid in developing effective management strategies.
Management Strategies:
According to Dr. McKelvy, no single management strategy fully prevents root rot in pulse crops. “Multiple strategies must be combined,” she said. Those include:
● Plant Peas and Lentils Early: In fields with Aphanomyces and Fusarium root rot history, plant peas and lentils early to reduce severity and improve yields (soil temperatures at 45.5–50°F–which are less conducive to these pathogens–at 2″ depth for 7 days post-planting).
● Broad Spectrum Fungicide Seed Treatments: Use fungicide seed treatments to protect against early-season pathogens, especially Pythium and Rhizoctonia, and enhance early crop establishment in cooler soils.
● High Quality, Disease Free Seeds: To minimize stress and vulnerability to root rots, Dr. McKelvy suggests using high quality, disease free seeds with high germination rates.
● Crop Rotation: Implement extended rotations, avoiding peas or lentils for 6 to 8 years, can reduce the buildup of root rot pathogens.
● Resistant Varieties: Dr. McKelvy recommends implementing extended rotations of at least 4 years between peas and lentils. This can reduce the buildup of root rot pathogens. In fields with a history of Aphanomyces root rot, rotations should be extended to 6 to 8 years between peas and lentils.
● Soil Health: Maintaining proper soil drainage and structure can mitigate conditions favorable to root rot development.
For a comprehensive understanding of the Saskatchewan survey and its implications, readers can access the full report here: 2024 Pulse Pest Survey Results(Saskatchewan Pulse Growers)
Call-to-Action:
Dr. McKelvy’s research program is currently looking for pea and lentil fields for soil sampling to determine which root rot pathogens are present in the field. If growers are interested in getting their field tested, they may email her at uta.mckelvy@montana.edu.
Montana State University Pulse Crops Working Group also publishes a blog with articles that summarize their research insights for the public, including several articles on root rot diagnosis and management: https://pulsecropsipm.org/news/
If you’ve encountered root rot in your pulse crops or have strategies to share, please leave a comment below. Your experiences and insights can help build a resilient pulse-growing community in Montana.
Key Statistics from Saskatchewan’s 2024 Survey:
● 85% of lentil fields showed root rot symptoms.
● 90% of field pea fields were affected by root rot.
● Average severity ratings: 1.7 (lentils), 2.2 (field peas) on a 1–7 scale.
Common Root Rot Pathogens:
● Aphanomyces euteiches
● Fusarium spp.
● Pythium spp.
● Rhizoctonia solani
Management Tips:
● Plant peas and lentils early
● Use broad spectrum fungicide seed treatments
● Extend crop rotation
● Practice extended crop rotations.
● Consider resistant varieties when available.
● Ensure proper soil drainage to prevent pathogen proliferation.
By implementing these strategies and staying informed, Montana pulse growers can proactively manage root rot risks and sustain healthy crop yields.
▶ Stay tuned to the Montana Pulse Crop Committee blog for more timely information impacting Montana’s pulse crop community.
