Pierluigi Bonello and Maria Bellizzi, Department of Plant Pathology, The Ohio State University, Columbus, Ohio; and Harry A. J. Hoitink, Department of Plant Pathology, The Ohio State University, Ohio Agricultural Research and Development Center, Wooster, Ohio.
Honeylocust (Gleditsia triacanthos) is native to the east-central United States and is an important nursery and ornamental plant. Growers typically produce plants of various sizes. Trees priced at $150 to $200 each (two- inch caliper) are commonly marketed at the wholesale level. Honeylocusts are very common in the urban landscape due to their pleasing form, light shade, hardiness, and tolerance to drought and salinity (Blair, 1990).
Although this tree species is susceptible to attacks and damage by multiple insect pests (e.g., plant bugs, spider mites, flatheaded borers, mimosa webworms, etc.), diseases have historically been a minor problem in the landscape and nursery (Blair, 1990).
Canker caused by Thyronectria austro-americana can occasionally cause mortality losses. Furthermore, aging honeylocusts become more susceptible with time to root rot and decay fungi such as Ganoderma lucidum which can kill the tree over a number of years. Unlike many other hardwoods, leaf diseases usually are not important (Hepting, 1971).