Poster Session: Diseases of Plants - New and Emerging Diseases
534-P
Understanding the emergent fruit rot disease of Winterberry holly.
F. Peduto Hand (1), S. LIN (1), N. J. Taylor (2), R. H. Zondag (3)
(1) The Ohio State University, Columbus, OH, U.S.A.; (2) C. Wayne Ellett Plant & Pest Diagnostic Clinic, Raynoldsburg, OH, U.S.A.; (3) The Ohio State University Extension, Painesville, OH, U.S.A.
Winterberry holly (Ilex sp.) is a deciduous ornamental shrub harboring colorful berries, whose cut stems are used in holiday decorations. Since 2012, winterberry producers in Ohio and several other states in the Midwestern and Eastern United States are confronted with a fruit rot problem of unspecified cause that is reducing yield of saleable plant material, income, and opportunities for market expansion. Spore trapping trials were set up in Spring 2014 at two orchards in northern Ohio. Microscope slides coated with petroleum jelly were hung on the plants and allowed to trap spores weekly. Spores were washed off the slides and plated onto PDA amended with antibiotics. The most represented colonies were counted and subcultured and subjected to identification. Colony counts were also correlated to meteorological data, including rainfall and average temperature. Fruit infection was monitored biweekly on 100 randomly collected berries. Any observed fungal colonies were subcultured onto PDA plates and subjected to identification. A few isolates were selected to conduct preliminary pathogenicity tests. The most represented fungal species recovered from the spore traps included Colletotrichum sp., Alternaria sp. and Fusarium sp. Species of Alternaria were also consistently isolated from the fruit samples. Preliminary pathogenicity tests of Alternaria sp. and Colletotrichum sp. showed that different cultivars might affect the ability of the pathogens to infect.