Field Resistance of American Sycamore ‘Davis’ to Canker Pathogens

Abstract American sycamores ( Platanus occidentalis L.) are found in many ecosystems and planted urban landscapes worldwide. The trees highly susceptible to anthracnose canker pathogens, causing leaf blight branch dieback. On Ohio State University campus Columbus, Ohio, an sycamore was observed thrive among symptomatic sycamores. healthy tree, subsequently protected as cultivar ‘Davis,’ vegetatively propagated tested for field resistance natural infection of pathogens compared the wildtype. Incidence severity necrosis, incidence dieback, tree death were evaluated 2 consecutive seasons. necrosis disconnected from dieback mortality, little no leaves produced on wildtype trees. By end second season, 7 out 12 dead, while all ‘Davis’ alive. Several recovered both wildtype, including Apiognomonia platani Diaporthe eres . latter had not been previously reported sycamore. Pathogenicity tests confirmed that D. is indeed pathogenic also significantly more resistant than development should be preferred over landscape.