Changes of Cut Orchid Quality after Fumigation with Clove and Cinnamon Essential Oils

Clove and cinnamon essential oils have been recently considered as effective alternative fumigants against thrips and mealybug, which are the major pests infecting exported orchid cut flowers in many countries. Therefore, this study aimed to investigate effects of clove and cinnamon essential oils in non-targeted fumigation on Dendrobium orchid cut flower. Changes in L*, a* and b* values, weight loss, polyphenoloxidase (PPO) activity, total phenolics and anthocyanin content were determined. All fumigations in this study were conducted using the essential oils at the concentrations of 0.0, 3.0 and 6.0 ml/m(3) for 1 h with 15-min air circulation in 1-m(3) glass chambers. The effects of eugenol under the same conditions were examined. The samples were evaluated prior to the treatments, immediately after the treatments, and 3 d after the treatments at 25 +/- 1 degrees C. The results showed a decrease of L* and a* values, and anthocyanin content in all groups, while b* value, percentage of weight loss and total phenolic content increased. PPO activity did not change throughout the sampling period. Remarkably, the orchids fumigated with clove and cinnamon essential oils, and eugenol at 3.0 ml/m(3) did not differ from the control. However, fumigations at 6.0 ml/m(3) reduced flower quality, leading to increased weight loss and petal discoloration.