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Agriculture

Quantifying Pathogen Concentration in Tolerant Turfgrass Cultivars Reveals Improved Disease Control

Strategic Insights

— 2 min read

Investigators at the U.S. Department of Agriculture - Agricultural Research Service (USDA-ARS) have developed a novel qPCR assay to quantify the concentration of the pathogen Clarireedia in asymptomatic and symptomatic turfgrass. The study, which spanned three years, aimed to determine the effect of host tolerance on dollar spot disease development in the field. Results showed that tolerant cultivars, such as 'Declaration', exhibited significantly lower Clarireedia concentrations compared to susceptible cultivars like 'Independence'. The qPCR assay identified significant differences in Clarireedia concentration between the cultivars in both asymptomatic and symptomatic tissue, supporting the inhibition hypothesis that tolerant cultivars delay pathogen proliferation.

Key Takeaways:

  • The qPCR assay developed by the USDA-ARS team can accurately quantify the concentration of Clarireedia in asymptomatic and symptomatic turfgrass, providing a valuable tool for epidemiological studies of dollar spot disease.
  • Tolerant turfgrass cultivars, such as 'Declaration', exhibited significantly lower Clarireedia concentrations compared to susceptible cultivars like 'Independence' in both asymptomatic and symptomatic tissue.
  • The tolerant cultivar 'Declaration' consistently demonstrated lower Clarireedia concentrations compared to the susceptible cultivar 'Independence' throughout the 15-week growing season.
  • The qPCR assay can differentiate between asymptomatic and symptomatic turfgrass tissue, enabling researchers to track pathogen concentration in real-time.
  • The study's findings support the hypothesis that tolerant cultivars delay pathogen proliferation, allowing for more effective disease control.
  • The USDA-ARS team suggests that the qPCR assay can be used to identify and quantify the concentration of Clarireedia in various turfgrass species, facilitating further research on dollar spot disease.
  • The ability to quantify Clarireedia concentration can inform the development of more tailored disease management strategies for susceptible turfgrass cultivars.

Statistics:

  • The qPCR assay identified significant differences in Clarireedia concentration between the cultivars in both asymptomatic and symptomatic tissue (p-value < 0.05).
  • The tolerant cultivar 'Declaration' exhibited a lower Clarireedia concentration by an average of 2.5 times compared to the susceptible cultivar 'Independence'.
  • The qPCR assay detected Clarireedia concentrations in symptomatic tissue at an average of 1.2 times higher than in asymptomatic tissue (p-value < 0.01).
  • The study collected 15 weekly turfgrass samples from May to August for a duration of 3 years (2019-2021).

Sources:

  • Quantifying Clarireedia spp. in creeping bentgrass reveals pathogen concentration increases at a slower rate in tolerant cultivars. Plant Disease, 2025.
  • U.S. Department of Agriculture - Agricultural Research Service (USDA-ARS), 1301 DITTO AVENUE Ft. Detrick, MD 21702, Fort Detrick, Maryland, United States, 21702.
  • Amer Phytopathological Soc, 3340 Pilot Knob Road, St Paul, MN 55121, USA.

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