Control of blue mold caused by Penicillium expansum on apples 'Empire' with fludioxonil and cyprodinil

• Published in: Canadian journal of plant pathology 2004-03, Vol.26 (1), p.70-75
• Main Authors: Errampalli, Deena, Crnko, Naomi
• Format: Article
• Language: English
• Subjects: apple; blue mold; Malus domestica; Mertect; Penicillium expansum; Scholar; Switch; Vangard
• ISSN: 0706-0661; 1715-2992
• DOI: 10.1080/07060660409507114

Penicillium expansum, one of the important causal agents of blue mold of apple in storages in Ontario, has developed resistance to thiabendazole, a postharvest fungicide, in some storages. In an attempt to develop alternate fungicides to thiabendazole, the protective effect of three fungicides, fludioxonil, cyprodinil, and a mixture of fludioxonil and cyprodinil, were evaluated for their efficacy against blue mold caused by thiabendazole-sensitive and -resistant isolates of P. expansum. The three fungicides were equally effective against thiabendazole-sensitive and -resistant isolates of P. expansum. Fenhexamid had no activity against P. expansum. No cross-resistance was observed between thiabendazole and fludioxonil or cyprodinil. Lower concentrations of fludioxonil (45 µg·mL -1 ), cyprodinil (50 µg·mL -1 ), and fludioxonil + cyprodinil (50 + 75 µg·mL -1 ) gave >97.0% control for up to 1 month, but higher concentrations of fludioxonil (100 µg·mL -1 ) and fludioxonil + cyprodinil (150 + 225 µg·mL -1 ) were required to control blue mold for 62 days at 4 °C. When the mixture was tested, antagonistic effect was observed at lower concentrations; however, higher concentrations completely controlled the disease. Fludioxonil and cyprodinil have modes of action different from each other and from that of the thiabendazole; they have the potential to be effective components in the resistance management for postharvest control of apple blue mold.