S05 - Session P1 - Methyl Bromide fumigation on export cut Dendranthema grandiflorum L. affects postharvest qualities

Authors: Yen-Hua Chen *, Yu-Hung Hsieh

As the top one cut flower of production in Taiwan, chrysanthemum ( Dendranthema grandiflorum L.) was exported to Japan largely in nearly two decades. However, in recent years the chrysanthemum exports to the Japanese market have decreased greatly due to neighboring competitors and market dynamics. To create more opportunities for chrysanthemum growers, we are eager to open new markets, and Australia is one of the potential export markets for Taiwan's floral industry. The quarantine for imported plants to Australia is required by the Australian government. But there is limited research about the effects of methyl bromide fumigation on cut chrysanthemum postharvest qualities. Therefore, in this study, two summer varieties of cut chrysanthemum were fumigated with methyl bromide 32g·m -3 for 2 hours right before or after 48 hours shipping simulation, and then the qualities of cut chrysanthemum during vase period were recorded. Methyl bromide fumigation for 2 hours killed pests, such as spider mites and thrips, nearly 100 % on chrysanthemum 'Huang Chin Jen' and 'Pai Ten Shing'. However, fumigation caused early leaf wilting of chrysanthemum seriously, especially for those flowers treating fumigation before shipping simulation that completely lost commercial values. Though the vase life of flowers in fumigation treatment after shipping simulation was not significantly affected, the flower diameter decreased more than 15 % compared to controls and showed parts of browning florets. To sum up, to export good quality chrysanthemum, growers should strengthen production management and pest controls for better flower quality and therefore be more tolerant to fumigation. Better timing of fumigation is after shipping to Australia to avoid serious damage on cut chrysanthemum.