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POSTERS: Fungicide and antibiotic resistance

Fungicide Resistance Profiles In Botrytis cinerea From Commercial Cut Flower Roses And Influence of Cultural Practices on Spore Movement
Melissa Munoz - Clemson University. James Faust- Clemson University, Guido Schnabel- Clemson University

Botrytis cinerea is a fungal pathogen that causes gray mold in cut roses. The infection affects rose quality and results in significant economical loses during production, and retail environments. Commercial growers rely on fungicide applications as one of the primary strategies for disease management. However, increasing reports of B. cinerea isolates resistant to different single-site fungicides in different crops around the world have become a concern. Crop sanitation and microclimate manipulation are also considered key pieces for disease management. Six commercial shipments containing rose cultivar Orange Crush were received from two greenhouses at a farm in Colombia. Additionally, four commercial shipments of cut roses cultivar Freedom were received from Africa, South and Central. A high proportion of isolates collected from Orange Crush showed resistance to thiophanatemethyl, iprodione, boscalid, and cyprodinil. Resistance to thiophanatemethyl and cyprodinil was frequently observed in Freedom isolates. The frequency of resistance to penthiopyrad, fenhexamid, fluopyram, isofetamid, and fludioxonil was variable. No resistance was observed to pydiflumetofen. Hierarchical clustering analysis was used to evaluate relationships between Botrytis spore count and production activities. A higher spore count was observed during the weekdays, compared with weekend days. High spore count was observed when dumping refreshing solutions, fungicide application, lime application, harvest, pinch, removal diseased tissue, supplemental watering, and sweeping of the central aisle occurred