Fungicidal activity of plant volatile compounds for controlling Monilinia laxa in stone fruit.

摘要

Nine plant-volatile compounds were tested for their activity against Monilinia laxa, the cause of brown rot in stone fruit. In vitro trials on conidial germination and mycelial growth showed a consistent fungicidal activity of trans-2-hexenal, carvacrol, and citral, whereas trans-cinnamaldehyde, hexanal, (-)-carvone, eugenol, 2-nonanone, and p-anisaldehyde exhibited a progressively lower inhibition. The best inhibitor of conidial germination was trans-2-hexenal (effective dose for 50 and 90% inhibition [ED50 and ED95]=7.53 and 9.4 micro l/liter, respectively; minimal inhibitory concentration [MIC]=12.3 micro l/liter), whereas carvacrol was the best inhibitor of mycelial growth (ED50 and ED95=2 and 3.4 micro l/liter, respectively; MIC=6.1 micro l/liter). The three most active compounds in in vitro studies also were tested in vivo as postharvest biofumigants. The best control of brown rot was with trans-2-hexenal (efficacy ranging from 46.2 to 80.3%, depending on cultivar), whereas citral and carvacrol resulted in a lower efficacy of 40 and 32.9%, respectively. Fumigation with trans-2-hexenal at concentrations that stopped decay did not cause any visible disorders to plum, whereas it was phytotoxic to apricot, peach, and nectarine and produced off-odors or off-flavors in all species of stone fruit tested..