795 ACTA UNIVERSITATIS AGRICULTURAE ET SILVICULTURAE MENDELIANAE BRUNENSIS Volume LXI 88 Number 3, 2013 http://dx.doi.org/10.11118/actaun201361030795 PLANT CRUDE EXTRACTS AND YEAST AS ALTERNATIVE TO SYNTHETIC FUNGICIDE FOR CONTROLLING POSTHARVEST GREEN MOULD ON CITRUS FRUIT Henik Sukorini, Somsiri Sangchote, Netnapis Khewkhom Received: December 11, 2012 Abstract SUKORINI HENIK, SANGCHOTE SOMSIRI, KHEWKHOM NETNAPIS: Plant crude extracts and yeast as alternative to synthetic fungicide for controlling postharvest green mould on citrus fruit. Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, 2013, LXI, No. 3, pp. 795–801 The objectives of this research was to evaluate the effectiveness of the combination of plant crude extracts and yeasts as an alternative to replace the synthetic fungicide to control green mould rot caused by Penicillium digitatum on citrus fruit. This pathogen caused 90% of citrus losses during the storage. Control of this pathogen mainly with chemicals, but concerned with environmental contamination, human health, and pathogen resistance, chemical treatment is frequently decreased. Eugenia caryophylata crude extracts and Candica utilis showed to be the best combination to attain a reduction in green mould incidence by 90.3% and disease severity by 96.26%. Furthermore, the combination of E. caryophylata crude extracts and C. utilis had a more potent antifungal activity than imazalil. The effectiveness of the combination of plant crude extractss and yeasts can be an alternative treatment to replace the synthetic fungicide to control P.digitatum on citrus fruit, but the application in the packaging line needs further investigation. citrus fruit, green mould, plant crude extracts, yeast, Penicillium digitatum Harvested citrus fruits are very susceptible to wound infection by Penicillium digitatum (Pers.:Fr.) Sacc, which is commonly known as green mould rot. It causes 90% of losses during the storage and also serious damages in commerce (Canamas et al., 2008). Minimizing wounds on fruit, proper temperature management, and postharvest fungicide treatments are the main methods of reducing losses by this pathogen (Eckert and Eaks, 1989). Applications of synthetic fungicides increase an environmental contamination and human health problems. In contrast, control of postharvest pathogens has been accomplished mainly with the use of chemicals. P. digitatum developed resistance to the fungicide thiabendazole (TBZ) in the California citrus industry in 1981 (Holmes and Eckert, 1999), sodium ortho-phenylphenate (SOPP) and imazalil 1-[2-(2,4-dichlorophenyl)-2- (2-prophenyloxy)ethyl]-1H-imidazole, and caused reduction in chemical efficacy (Holmes and Eckert, 1999). Therefore, alternative strategies to control postharvest disease of citrus fruits are needed. Recently, integrated control is oſten used to enhance the effectiveness of a control measure. Biological control has emerged as one of the most promising alternative, antagonist organism has been used either alone or as part of an integrated control strategy to reduce synthetic fungicide (Fan and Tian, 2000). Combination of Rhodotorula glutinis with 1 mmolL −1 and NH 4 Mo provided an effective control on P. expansum and Alternaria alternata than applying the yeast or NH 4 Mo alone. P. expansum completely eliminated by combination of Metschnikowia pulcherrima, Cryptococcus laurentii, and sodium bicarbonate on fruit stored under CA conditions (Conway et al., 2007). Mixture of Pantoea agglomerans CPA-2, 3% sodium carbonate or sodium bicarbonate (SBC) aqueous solutions heated to