台灣百合之疫病

Abstract

Phytophthora blight of lily was noticed recently in central Taiwan. The disease was found on Lilium asiatic hybrid, L. oriental hybrid, and L. longiflorum. A total of 51 isolates (33 Al: 18 A2) of P. parasitica was isolated from diseased flowers, leaves, stems, bulbs, and roots of lily plants from 1989 to 1991. All six tested isolates of P. parasitica caused flower blight, stem and leaf rot, root rot and wilting of plants on all three Lilium species in pathogenicity tests. P. parasitica was reisolated from the diseased tissues of inoculated plants. Lily isolates of P. parlωitica grew on V -8 agar medium from 12 to 36℃. The optimum growth temperatures were 28-32℃ for A1 isolates and 24-28℃ for A2 isolates. Sporangia were spherical to ovate, non-deciduous, and papillate ranging from 37.5-81 X 30-47.5μm (av. 46.9 X 39.0μm) for A1 isolates and 42.5-63 X 30-49μm (av. 51.8 X 4 1. 0μm) for A2 isolates. Sizes of selfed-oospores produced through chemical stimulation were 15.0-27 .5 μm (av. 22.5 μm) for A1 isolates and 20.0-29.0μm (av. 24.4 μm) for A2 isolates.