title: Chemical management in fungicide sensitivity of Mycosphaerella fijiensis collected from banana fields in México.
abstract: The chemical management of the black leaf streak disease in banana caused by Mycosphaerella fijiensis (Morelet) requires numerous applications of fungicides per year. However this has led to fungicide resistance in the field. The present study evaluated the activities of six fungicides against the mycelial growth by determination of EC50 values of strains collected from fields with different fungicide management programs: Rustic management (RM) without applications and Intensive management (IM) more than 25 fungicide application/year. Results showed a decreased sensitivity to all fungicides in isolates collected from IM. Means of EC50 values in mg L(-1) for RM and IM were: 13.25 ± 18.24 and 51.58 ± 46.14 for azoxystrobin, 81.40 ± 56.50 and 1.8575 ± 2.11 for carbendazim, 1.225 ± 0.945 and 10.01 ± 8.55 for propiconazole, 220 ± 67.66 vs. 368 ± 62.76 for vinclozolin, 9.862 ± 3.24 and 54.5 ± 21.08 for fludioxonil, 49.2125 ± 34.11 and 112.25 ± 51.20 for mancozeb. A molecular analysis for β-tubulin revealed a mutation at codon 198 in these strains having an EC50 greater than 10 mg L(-1) for carbendazim. Our data indicate a consistency between fungicide resistance and intensive chemical management in banana fields, however indicative values for resistance were also found in strains collected from rustic fields, suggesting that proximity among fields may be causing a fungus interchange, where rustic fields are breeding grounds for development of resistant strains. Urgent actions are required in order to avoid fungicide resistance in Mexican populations of M. fijiensis due to fungicide management practices.
authors.affiliation: Departamento de Química Universidad Autónoma de Guadalajara GuadalajaraJalisco México.
authors.forename: Alejandra
authors.initials: A
authors.lastname: Aguilar-Barragan
authors.affiliation: Departamento de Química Universidad Autónoma de Guadalajara GuadalajaraJalisco México.
authors.forename: Ana Elisa
authors.initials: AE
authors.lastname: García-Torres
authors.affiliation: Instituto de Ingeniería Universidad Autónoma de Baja California Mexicali B.C. México.
authors.forename: Olga
authors.initials: O
authors.lastname: Odriozola-Casas
authors.affiliation: Instituto de Ingeniería Universidad Autónoma de Baja California Mexicali B.C. México.
authors.forename: Gloria
authors.initials: G
authors.lastname: Macedo-Raygoza
authors.affiliation: Departamento de Química Universidad Autónoma de Guadalajara GuadalajaraJalisco México.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Ogura
authors.affiliation: Laboratorio de Biotecnología de la Universidad de Colima Campus Tecomán TecománColima México.
authors.forename: Gilberto
authors.initials: G
authors.lastname: Manzo-Sánchez
authors.affiliation: Unidad de Biotecnología Centro de Investigación Científica de Yucatán Mérida Yucatán México.
authors.forename: Andrew C
authors.initials: AC
authors.lastname: James
authors.affiliation: Unidad de Bioquímica y Biología Molecular de Plantas Centro de Investigación Científica de Yucatán MéridaYucatán México.
authors.forename: Ignacio
authors.initials: I
authors.lastname: Islas-Flores
authors.affiliation: Departamento de Química Universidad Autónoma de Guadalajara GuadalajaraJalisco México.
authors.forename: Miguel J
authors.initials: MJ
authors.lastname: Beltrán-García
mesh_terms: D001203:Ascomycota / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D025141:Drug Resistance, Fungal; D004363:Drug Utilization; D005659:Fungicides, Industrial / Q000494:pharmacology*; D008800:Mexico; D028521:Musa / Q000382:microbiology*; D020125:Mutation, Missense; D010935:Plant Diseases / Q000382:microbiology* / Q000517:prevention & control / Q000628:therapy; D014404:Tubulin / Q000235:genetics
chemical_list: D005659:Fungicides, Industrial; D014404:Tubulin
keywords: Mycosphaerella fijiensis; Sigatoka; banana; fungicides; sensitivity