Submitted to: Plant Disease
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/12/2006
Publication Date: 7/18/2006
Citation: Smilanick, J.L., Mlikota, G.G., Fassel, R., Mercier, J. 2006. Influence of temperature, inoculation interval, and dosage on biofumigation with muscodor albus to control postharvest gray mold on grapes. Plant Disease. 90: 1019-1025. Interpretive Summary: Gray mold is a fungal rot that destroys table grapes after harvest and typically shortens their storage and shipping life; currently, sulfur dioxide gas is used to control this problem, but the gas can harm the berries and has other regulatory issues that may curtail its use. Using a biological control approach, we evaluated placement of fungus within grape packages that released vapors to control gray mold. In this work, we showed this approach could successfully manage this disease.
Technical Abstract: Gray mold incidence (GMI) on berries inoculated with Botrytis cinerea 3, 24, or 48 h before continuous exposure to volatiles of Muscodor albus at 50 g rye culture/kg of berries during 7 days of storage at 20C was 0.8, 10, or 52.5%, respectively, and 65.8% among control berries. GMI on berries inoculated 3, 24, or 48 h before exposure to M. albus volatiles at 50 g/kg of berries during 20 days of storage at 5C was 10.8, 25.8, or 32.5%, respectively, and 45.8% among controls. GMI on inoculated clusters was reduced from 20.2% among controls to less than 1% when M. albus was present at 5 g/kg of fruit or higher inside clamshell boxes for 7 days at 15C. In grapes commercially packaged in ventilated polyethylene cluster bags, GMI was 40.5% among controls and 11.1 or 6.7%, respectively, when M. albus was present at 5 or 20 g/kg of grapes. GMI on similarly packaged, inoculated grapes incubated for 28 days at 0.5C was reduced from 42.8% among controls to 4.8 or 4.0%, respectively, with M. albus rates of 5 or 10 g/kg. M. albus controlled gray mold within commercial packages at cold and ambient temperatures. Within 24 h of inoculation, higher M. albus rates (>50 g/kg at 20C or 100 g/kg at 5C) eradicated infections so control persisted after M. albus removal. Lower rates (<20 g/kg) worked if M. albus was present; once removed, B. cinerea resumed growth and GMI increased.