Canadian Journal of Plant Pathology (2002) 24, 154-161

Ting Zhou, John Northover, Karin E. Schneider and Xuewen Lu (2002)
Interactions between Pseudomonas syringae MA-4 and cyprodinil in the control of blue mold and gray mold of apples
Canadian Journal of Plant Pathology 24 (2), 154-161
Abstract: Blue mold [Penicillium expansum] and gray mold [Botrytis cinerea] are the principal postharvest diseases of apples in Ontario. In an attempt to develop new control measures, the efficacies of two fungicides, cyprodinil and fenhexamid, and a biocontrol agent, Pseudomonas syringae MA-4, were assessed. Surface-disinfested apples were wounded and inoculated with a 20-µL drop containing either P. expansum (1 × 10⁴ conidia/mL) or B. cinerea (3 × 10⁴ conidia/mL), combined with a range of concentrations of either fungicide. Cyprodinil controlled blue mold and gray mold by over 90% at 25 and 5 µg/mL, respectively. Fenhexamid controlled gray mold by 98% at 10 µg/mL but was inactive against blue mold. Cyprodinil was combined with strain MA-4 to control both diseases in separate experiments. Against blue mold, cyprodinil and strain MA-4 provided >90% control at concentrations of 20 µg/mL and 3 × 10⁷ CFU/mL, respectively, on 'Northern Spy' apples. The addition of cyprodinil at concentrations of 2.5 to 20 µg/mL to treatments with strain MA-4 at 3 × 10⁶ CFU/mL significantly increased blue mold control (35–91%) compared with the strain MA-4 alone treatment (11%). However, there were some antagonistic effects between strain MA-4 and cyprodinil at 2.5–10 µg/mL on 'Jonagold' apples. Against gray mold on 'Northern Spy' apples, cyprodinil gave 85% control at 2.5 µg/mL, and strain MA-4 gave 77% control at 3 × 10⁸ CFU/mL. A combination of cyprodinil and strain MA-4 at concentrations of 2.5 µg/mL and 1 × 10⁸ CFU/mL, respectively, controlled gray mold by 100%. Cyprodinil was not bacteriocidal and at concentrations of 5 and 20 µg/mL had no effect on strain MA-4 populations at inoculation sites.

La moisissure bleue [Penicillium expansum] et la moisissure grise [Botrytis cinerea] sont les principales maladies d'entreposage du pommier en Ontario. En vue de développer de nouveaux moyens de lutte, l'efficacité de deux fongicides, le cyprodinile et le fenhexamide, et d'un agent de lutte biologique, le Pseudomonas syringae MA-4, fut évaluée. Des pommes désinfectées en surface furent blessées et inoculées avec une goutte de 20 µL contenant soit du P. expansum (1 × 10⁴ conidies/mL) ou du B. cinerea (3 × 10⁴ conidies/mL), en combinaison avec diverses concentrations de chaque fongicide. À 25 et 5 µg/mL respectivement, le cyprodinile réprima plus de 90% de la moisissure bleue et de la moisissure grise. Le fenhexamide réprima 98% de la moisissure grise à 10 µg/mL, mais fut inactif contre la moisissure bleu. Le cyprodinile fut combiné à l'isolat MA-4 pour lutter contre les deux maladies dans des expériences séparées. Contre la moisissure bleue sur la pomme 'Northern Spy', le cyprodinile et l'isolat MA-4 à des concentrations respectives de 20 µg/mL et de 3 × 10⁷ unités formant colonies (UFC)/mL ont procuré plus de 90% de protection. L'addition de cyprodinile à des concentrations de 2,5 à 20 µg/mL aux traitements avec l'isolat MA-4 à 3 × 10⁶ UFC/mL augmenta significativement la répression de la moisissure bleue (35–91%) par comparaison avec l'isolat MA-4 seul (11%). Cependant, il y eu quelques effets antagonistes entre l'isolat MA-4 et le cyprodinile entre 2,5 et 10 µg/mL sur des pommes 'Jonagold'. Contre la moisissure grise sur des pommes 'Northern Spy', le cyprodinile donna 85% de répression à 2,5 µg/mL, et l'isolat MA-4 donna 77% de répression à 3 × 10⁸ UFC/mL. Une combinaison de cyprodinile et de l'isolat MA-4 à des concentrations de respectivement 2,5 µg/mL et 1 × 10⁸ UFC/mL enraya 100% de la moisissure grise. Le cyprodinile ne fut pas bactéricide et, à des concentrations de 5 et 20 µg/mL, n'eut aucun effet sur les populations de l'isolat MA-4 aux sites d'inoculation.
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Link to article at publishers website
Database assignments for author(s): Ting Zhou

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
resistance to pesticides
formulation/storage of bioagents

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Botrytis cinerea	Stored fruits/vegetables
	Penicillium expansum	Stored fruits/vegetables
Pseudomonas syringae (antagonist)	Botrytis cinerea	Stored fruits/vegetables
Pseudomonas syringae (antagonist)	Penicillium expansum	Stored fruits/vegetables