title: Methods to control ectomycorrhizal colonization: effectiveness of chemical and physical barriers.
abstract: We conducted greenhouse experiments using Douglas-fir (Pseudotsuga menziesii var. glauca) seedlings where chemical methods (fungicides) were used to prevent ectomycorrhizal colonization of single seedlings or physical methods (mesh barriers) were used to prevent formation of mycorrhizal connections between neighboring seedlings. These methods were chosen for their ease of application in the field. We applied the fungicides, Topas (nonspecific) and Senator (ascomycete specific), separately and in combination at different concentrations and application frequencies to seedlings grown in unsterilized forest soils. Additionally, we assessed the ability of hyphae to penetrate mesh barriers of various pore sizes (0.2, 1, 20, and 500 microm) to form mycorrhizas on roots of neighboring seedlings. Ectomycorrhizal colonization was reduced by approximately 55% with the application of Topas at 0.5 g l(-1). Meshes with pore sizes of 0.2 and 1 microm were effective in preventing the formation of mycorrhizas via hyphal growth across the mesh barriers. Hence, meshes in this range of pore sizes could also be used to prevent the formation of common mycorrhizal networks in the field. Depending on the ecological question of interest, Topas or the employment of mesh with pore sizes <1 microm are suitable for restricting mycorrhization in the field.
authors.affiliation: Department of Forest Sciences, University of British Columbia, Vancouver, B.C., V6T 1Z4, Canada. fteste@interchange.ubc.ca.
authors.forename: François P
authors.initials: FP
authors.lastname: Teste
authors.affiliation: Department of Botany, University of British Columbia, Vancouver, B.C., V6T 1Z4, Canada.
authors.forename: Justine
authors.initials: J
authors.lastname: Karst
authors.affiliation: Biology and Physical Geography Unit, University of British Columbia Okanagan, 3333 University Way, Kelowna, B.C., V1V 1V7, Canada.
authors.forename: Melanie D
authors.initials: MD
authors.lastname: Jones
authors.affiliation: Department of Forest Sciences, University of British Columbia, Vancouver, B.C., V6T 1Z4, Canada.
authors.forename: Suzanne W
authors.initials: SW
authors.lastname: Simard
authors.affiliation: Biology and Physical Geography Unit, University of British Columbia Okanagan, 3333 University Way, Kelowna, B.C., V1V 1V7, Canada.
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Durall
mesh_terms: D004305:Dose-Response Relationship, Drug; D005659:Fungicides, Industrial / Q000494:pharmacology*; D038821:Mycorrhizae / Q000187:drug effects* / Q000378:metabolism*; D018517:Plant Roots / Q000382:microbiology; D028224:Pseudotsuga / Q000382:microbiology*; D036226:Seedlings / Q000382:microbiology
chemical_list: D005659:Fungicides, Industrial