Activity of Azole Fungicides and ABC Transporter Modulators on Mycosphaerella graminicola

• Published in: Journal of phytopathology Vol. 150; no. 6; pp. 313 - 320
• Main Authors: STERGIOPOULOS, I., DEWAARD, M. A.
• Format: Journal Article
• Language: English
• Published: Berlin Germany Blackwell Verlag GmbH 01-06-2002; Blackwell
• Subjects: ABC transporters; azoles; Biological and medical sciences; Chemical control; Control; EPS; Fundamental and applied biological sciences. Psychology; Fungal plant pathogens; interaction in mixtures; Laboratorium voor Fytopathologie; Laboratorium voor Phytopathologie; Laboratory of Phytopathology; modulators; Mycosphaerella graminicola; Phytopathology. Animal pests. Plant and forest protection; Additivity; Monocotyledones; Plant pathogen; Pesticides; Cereal crop; Fungicide; Fungi; Mycosphaerella graminicola; Gramineae; Angiospermae; Chemical control; Triazole derivatives; Ascomycetes; Spermatophyta; ABC transporter; Triticum aestivum; Thallophyta
• ISSN: 0931-1785; 1439-0434
• DOI: 10.1046/j.1439-0434.2002.00761.x

The antimicrobial activity of the azole fungicides cyproconazole and propiconazole as single active ingredients and in mixtures with the ATP‐Binding Cassette (ABC) transporter modulators rhodamine 6G, quercetin, quinidine, and verapamil and the strobilurin kresoxim‐methyl was assessed against the wheat pathogen Mycosphaerella graminicola. Interactions amongst these compounds were evaluated on germination and germ tube growth of pycnidiospores using the Colby and Wadley method. Water agar proved to be the best test medium since all pycnidiospores germinated within 24 h of incubation and apical germ tube growth dominated over bud formation by intermediate cells. Analysis with the Colby method revealed that interactions between the compounds in all mixtures tested on germination of pycnidiospores were additive. With regard to germ tube growth, mixtures of cyproconazole and verapamil or kresoxim‐methyl displayed a synergistic interaction. Analysis of mixtures of cyproconazole and kresoxim‐methyl with the Wadley method revealed that the interaction between the two compounds was purely additive. These results indicate that the Colby method overestimated the interaction between these two compounds in a mixture.