title: Development of selective media for the isolation and enumeration of Alternaria species from soil and plant debris.
abstract: A new semi-selective medium, acidified weak potato-dextrose agar (AWPDA) with Mertect (active ingredient: thiabendazole), was developed for the isolation and enumeration of Alternaria species from samples of soil and plant debris. The medium was selected based on growth inhibition tests against Alternaria and several other commonly encountered saprobic fungi utilizing three antifungal agents, Botran (active ingredient: dichloran), Bayleton (active ingredient: triadimefon), and Mertect, and two basal media, acidified potato-dextrose agar (APDA) and AWPDA. Botran inhibited growth of Rhizopus stolonifer moderately, but had little effect on Cladosporium cladosporoides, Fusarium oxysporum, Penicillium chrysogenum, or Trichoderma harzianum. Bayleton inhibited growth of R. stolonifer and C. cladosporoides severely, and inhibited growth of F. oxysporum, P. chrysogenum, and T. harzianum moderately. Mertect inhibited growth of C. cladosporoides, F. oxysporum, P. chrysogenum, and T. harzianum completely, but had little or moderate effect on R. stolonifer. All three antifungal agents inhibited growth of Alternaria species slightly or moderately. The combination of Bayleton and Mertect inhibited growth of all fungi severely. A comparison of recovery rates of Alternaria from soil and plant debris samples on AWPDA with Mertect and weak potato-dextrose agar (WPDA) revealed that Alternaria spp. accounted for 63.6%-81.0% of recovered fungal isolates on AWPDA with Mertect as compared to 0.6%-2.7% of recovered isolates on WPDA. The AWPDA medium with Mertect exhibited superior selective growth of Alternaria species from samples of soil and plant debris, and will be useful in studies where the recovery and enumeration of Alternaria species is necessary.
authors.affiliation: Department of Plant Sciences, College of Agriculture, University of Arizona, Tucson 85721-0036, USA.
authors.forename: Soon Gyu
authors.initials: SG
authors.lastname: Hong
authors.forename: Barry M
authors.initials: BM
authors.lastname: Pryor
mesh_terms: D000528:Alternaria / Q000187:drug effects / Q000254:growth & development* / Q000302:isolation & purification*; D000814:Aniline Compounds / Q000494:pharmacology; D000969:Antinematodal Agents / Q000494:pharmacology; D002963:Cladosporium / Q000187:drug effects / Q000254:growth & development; D015169:Colony Count, Microbial; D003470:Culture Media / Q000737:chemistry*; D005659:Fungicides, Industrial / Q000494:pharmacology; D005670:Fusarium / Q000187:drug effects / Q000254:growth & development; D009172:Mycology / Q000379:methods; D010408:Penicillium chrysogenum / Q000187:drug effects / Q000254:growth & development; D010944:Plants / Q000382:microbiology*; D012233:Rhizopus / Q000187:drug effects / Q000254:growth & development; D012988:Soil Microbiology; D013827:Thiabendazole / Q000494:pharmacology; D014230:Triazoles / Q000494:pharmacology; D014242:Trichoderma / Q000187:drug effects / Q000254:growth & development
chemical_list: D000814:Aniline Compounds; D000969:Antinematodal Agents; D003470:Culture Media; D005659:Fungicides, Industrial; D014230:Triazoles; C032910:triadimefon; C004354:dicloran; D013827:Thiabendazole