Harry A. J. Hoitink, Professor, Department of Plant Pathology, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, Ohio; Carol A. Musselman and Terry L. Moore, Research Assistants, Department of Plant Pathology, Ohio Agricultural Research and Development Center, The Ohio State University; Leona E. Horst, Research Assistant; Charles R. Krause, Adjunct Associate Professor, U.S. Department of Agriculture, Agricultural Research Service, Application Technology Research Unit, Wooster, Ohio; Randy A. Zondag, Ohio State University Extension, Chair and Extension Agent, Lake County, Painesville, Ohio; and Hannah Mathers, Assistant Professor, The Ohio State University, Department of Horticulture and Crop Science, Columbus, Ohio.
Suppression of Phytophthora Leaf Blight and Stem Dieback of Pieris japonica with T382
Liners of Pieris japonica (pint-sized pots) were transplanted into 1-gallon containers on June 3, 2002.
Container media included:
During a week of rainy weather in late July, 2002, a severe epidemic of Phytophthora dieback developed on Pieris on blocks of 525 plants produced in each medium. The percentage of plants with severe dieback or killed by the disease in the mix inoculated with T382 (4%) was considerably below the value observed on plants in the composted cow-manure-amended medium (26%).
In conclusion, this batch of compost did not naturally suppress this disease and that agreed with laboratory studies not presented here. Inoculation of the mix during its formulation in the cooperating nursery with T382 proved effective for suppression of Phytophthora dieback of Pieris japonica.