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ARS Home » Southeast Area » Poplarville, Mississippi » Southern Horticultural Research Unit » Research » Publications at this Location » Publication #179054
Title: INFECTION PROCESS OF ERYSIPHE PULCHRA ON FLOWERING DOGWOOD LEAVES AND GLASS SLIDES

Author
item LI, Y - UNIV OF TENN
item WINDHAM, M - UNIV OF TENN
item TRIGIANO, R - UNIV OF TENN
item Fare, Donna
item Spiers, James
item Copes, Warren

Submitted to: American Phytopathological Society Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 5/1/2005
Publication Date: 6/1/2005
Citation: Li, Y.H., Windham, M.T., Trigiano, R.N., Fare, D.C., Spiers, J.M., Copes, W.E. 2005. Infection process of erysiphe pulchra on flowering dogwood leaves and glass slides. American Phytopathological Society Annual Meeting 95:S61.

Interpretive Summary:

Technical Abstract: Spore germination, infection structure formation, and colony development of Erysiphe pulchra, the causal agent of powdery mildew of dogwood, on glass slides and leaf disks of a susceptible flowering dogwood line were examined using light and scanning electron microscopy. On both glass slides and leaf disks, conidia germinated within 2 h after inoculation (hai). One to four germ tubes grew from two poles of a conidium, one or two of the germ tubes formed initial appressoria, and only one of the germ tubes with initial appressoria formed secondary appressoria. However, formation of initial and secondary appressoria was delayed on glass slides (48 and 72 hai, respectively) compared to that on dogwood leaf disks (3 and 24 hai, respectively). Branching hyphae did not grow from germinated conidia on glass slides. However, on dogwood leaf disks, branched hyphae were observed 48 hai. In epidermal cells, the fungus formed compact and globose haustoria. Conidia formation on conidiophores started on leaf disks 7 days after inoculation. Conidia germinated and formed initial and secondary appressoria on glass slides without establishing a parasitic relationship, but food sources in conidia could not provide enough energy and nutrition for growth of branched hyphae.