Efficacy of Copper and New Bactericides for Managing Olive Knot in California

Baseline sensitivities were established for kasugamycin and oxytetracycline for 147 strains of Pseudomonas savastanoi pv. savastanoi collected from olive knots throughout California. Minimum inhibitory concentrations for ≥95% growth inhibition ranged from 1.86 to 11.52 and 0.13 to 0.40 µg/ml for kas...

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Veröffentlicht in:Plant disease. - 1997. - 102(2018), 5 vom: 01. Mai, Seite 892-898
1. Verfasser: Nguyen, K A (VerfasserIn)
Weitere Verfasser: Förster, H, Adaskaveg, J E
Format: Online-Aufsatz
Sprache:English
Veröffentlicht: 2018
Zugriff auf das übergeordnete Werk:Plant disease
Schlagworte:Journal Article Research Support, Non-U.S. Gov't Aminoglycosides Anti-Bacterial Agents Copper 789U1901C5 kasugamycin O957UYB9DY Oxytetracycline X20I9EN955
Beschreibung
Zusammenfassung:Baseline sensitivities were established for kasugamycin and oxytetracycline for 147 strains of Pseudomonas savastanoi pv. savastanoi collected from olive knots throughout California. Minimum inhibitory concentrations for ≥95% growth inhibition ranged from 1.86 to 11.52 and 0.13 to 0.40 µg/ml for kasugamycin and oxytetracycline, respectively. In copper sensitivity evaluations, 95.3% of the strains collected grew at concentrations of metallic copper equivalent (MCE) of <20 µg/ml, 2.7% grew at MCE between 20 and 30 µg/ml (moderately sensitive), and 2% grew at MCE of 150 µg/ml (resistant). Copper resistance was never reported previously in the olive knot pathogen, and pathogenicity studies confirmed a high virulence of the copper-resistant strains. In comparative field studies, kasugamycin at 200 µg/ml performed equally to the standard copper hydroxide treatment (MCE of 1,260 µg/ml) for reducing knot development on lateral wounds of Arbequina and Manzanillo olive inoculated with a copper-sensitive strain and was better than copper using a highly copper-resistant strain. Oxytetracycline at 200 µg/ml was not as effective as copper or kasugamycin but significantly reduced the disease as compared with the untreated control. Field studies on application timings of copper, kasugamycin, and copper-kasugamycin mixtures to inoculated wounds indicated that treatments within 24 h of inoculation resulted in higher disease control than applications at later times. In greenhouse trials, copper or copper-kasugamycin applied to wounds 7 days before inoculation persisted and reduced knot incidence by >50%. Our findings indicate that kasugamycin is an effective bactericide for controlling olive knot and that the time of any bactericide application after inoculation is critical in managing the disease
Beschreibung:Date Completed 25.02.2019
Date Revised 25.02.2019
published: Print-Electronic
Citation Status MEDLINE
ISSN:0191-2917
DOI:10.1094/PDIS-08-17-1162-RE