Journal of Taiwan Agricultural Research

Author:Guo-Jun Liao, Ting-Fang Hsieh*, and Hong-Rong Chen

Abstract:

    Fusarium yellow, caused by Fusarium solani, is a serious disease of Phalaenopsis spp. in ship-ment and it is one of the major factors affecting the export market of this fower crop in Taiwan.  The objective of this study was to determine effect of chemical treatment on prevention of Fusarium yel-low of Phalaenopsis seedlings under simulated conditions in shipment, using white-fower Phalaenopsis Sogo Yukidian ‘V3’.  Seedlings (18-month-old) were treated with 50% prochlorate manganese WP or 1% chitosan for 3 days and then inoculated with spore suspension (10⁵ spore/mL) of F. solani with or without wounding of orchid plants.  The wounding treatment was done by puncturing the leaf sheath of each orchid plant using a bundle of 5 needles.  For the treatment of control, seedlings were treated with sterile water and inoculated with F. solani, with or without wounding.  All the plants, treated or untreated control, were incubated in a growth chamber without lighting at 18℃ for 20 and 26 days and they were rated for disease severity, using a scale of 0 to 4 (0 = no symptom on leaf and 4 = leaf yellowing).  Results of the frst experiment showed that treatment of wounded plants with prochlorate manganese or chitosan for 20 or 26 days signifcantly (P < 0.05) reduced severity of Fu-sarium yellow of Phalaenopsis.  However, the result of this experiment was not repeatable in the two subsequent experiments.  The inconsistency of these experiments indicates that spraying Phalaenopsis plants with prochlorate manganese or chitosan once is inadequate for protection of plants from devel-oping Fusarium yellow during the period of shipment for 20 or 26 days.

Key words:Phalaenopsis, Simulated shipment conditions, Fusarium solani, Prochlorate manganese, Chitosan

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