| Summary: | 碩士 === 國立臺灣大學 === 植物病蟲害學系 === 81 === Twenty tow flowerseed samples colleted from local seed compani-
es were used for detecting the presence of seed-borne fungi.
The blotter method was applied in this study. Totally , 24
different fungi were detected from these 22 seed samples. A.
carthami, C. senegalenesis, D. purpureofuscus,D. frumetacei
and P. chartarum were newly recorded in Taiwan. A. carthami,
C. dematium, C.lunata ,D. rostrata and Phoma sp. were proved to
be pathogenic. They de- creased the germination rate
andhindered the seedling development of zinnia, celeosia,
globe amaranth and French marigold, respec- tively. A. carthami
was proved to be a seed-transmitted pathogen. Bas- ed upon the
colony, hape and size of conidia, as well as pathoge- nicity,
A. carthami was quite different from A. zinniae. A. car- thami
could infect zinnia at every development stage. Once germi-
nation occurred, appressoria was formed and penetration was
ini- tiated within 48hrs after inoculation. Invaded
mesophyll cell were disintegrated within 96hrs after
inoculation. In vitro, di- fenoconazole , flusilazole ,
hexaconazole and pyrifenox inhibited significantly the growth
of A. carthami. Two isolates of antago- nistic Bacillius spp.
were able to inhibit the growth and caused germ tube swollen,
malformed of A. carthami. Spraying Bacillus spp. was
singificently effective to control zinnia leaf spot cau- sed by
A. carthami. The effectiveness of Bacillus spp. to control A.
carthami was even significently better than mancozeb and hexa-
conazole. Pyrifenox were the effective fungicide to control
zi- nnia leaf spot.
|
|---|
