Control of green mold ( Penicillium digitatum ) on tangerine fruit by hot water and imazalil treatment, and with antagonistic yeasts.

摘要

Tangerine fruits cv. Sai-Namphaung were treated with hot water at 50, 52, 54 and 56 degrees C for 2 min. to control green mold rot. Hot water at 52, 54 and 56 degrees C could reduce decay significantly on treated fruits to 75, 66.7, 43.3 and 20% respectively (100% in untreated). Combination of hot water at 56 degrees C and imazalil at 500 ppm for 2 min. dipping completely controlled this disease. Four selected yeasts including Candida utilis, Candida tropicalis, Debaromyces hansenii, and Pichia sp. were also evaluated for their antagonistic properties in controlling green mold rot. C. utilis was a promising yeast; application of C. utilis suspension 12 or 24 h before pathogen inoculation showed the lowest disease incidence (0%) as compared with application of yeasts and pathogen simultaneously (20.5, 46.2%) or application of yeasts 12 or 24 h after pathogen inoculation (41.0, 61.5%). Candida utilis had an effect on conidial germination and germ tube elongation of P. digitatum on citrus fruits. Green mold rot was completely control by application of C. utilis in combination with 2% sodium bicarbonate on citrus fruits and then inoculation with Penicillium digitatum, as compared with fruits treated with 2% sodium bicarbonate or antagonistic yeast alone.