Measuring root disease suppression in response to a compost water extract

Phytopathology. 2013 Mar;103(3):255-60. doi: 10.1094/PHYTO-06-12-0145-R.


Commercial application of compost to prevent plant disease is hindered by variable performance. Here, we describe the use of a growth pouch assay to measure impact of a compost water extract (CWE) on root infection under controlled conditions. Most pea roots (≥95%) inoculated with Fusarium solani or Phoma pinodella spores rapidly develop a single local lesion in the region of elongation. In the presence of CWE, infection of pea roots grown in pouches was reduced by 93 to 100%. CWE used as a drench on pea seedlings grown in sand also resulted in 100% protection but, in a heavy clay soil, infection was reduced by <50%. CWE filtered to remove microorganisms did not inhibit frequency of F. solani infection, and resulted in increased local lesion development on individual roots. CWE inhibited mycelial growth of both pea- and cucumber-infecting isolates of F. solani in culture but exerted <40% protection against cucumber root infection. CWE treatment of pea but not cucumber was associated with retention of a sheath of border cells interspersed with bacteria covering the region of elongation. Growth pouch assays may provide a system to monitor effects of specific compost mixtures on root-rhizosphere interactions, and to identify variables influencing disease control.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Ascomycota / growth & development
  • Ascomycota / pathogenicity
  • Crops, Agricultural
  • Cucumis sativus / immunology*
  • Cucumis sativus / microbiology
  • Cucumis sativus / physiology
  • Disease Susceptibility
  • Fusarium / growth & development
  • Fusarium / pathogenicity*
  • Peas / immunology*
  • Peas / microbiology
  • Peas / physiology
  • Plant Diseases / immunology*
  • Plant Diseases / microbiology
  • Plant Roots / immunology*
  • Plant Roots / microbiology
  • Plant Roots / physiology
  • Seedlings / immunology
  • Seedlings / microbiology
  • Seedlings / physiology
  • Soil / chemistry
  • Water


  • Soil
  • Water