Improving Nursery Plant Health for Nurseries in the Pacific Northwest

Goals / Objectives
Evaluate environmental factors, production practices, and disease control measures affecting the spread of boxwood blight in Oregon nurseries.

Project Methods
This research will investigate the effects of environment, nursery production practices, and disease control practices on disease development, detection, and spread of boxwood blight. Field, greenhouse, growth chamber, and laboratory experiments will be conducted to evaluate how different treatments for temperature, humidity, irrigation,fungicide application, plant spacing, or other relevant factors affect the growth of pathogen cultures, the incidence and severity of boxwood blight on inoculated plants, and the movement of boxwood blight from diseased plants to healthy plants. Treatments will be chosen based on cultivars and environmental conditions observed in the Oregon boxwood industry, such as shipping containers, nursery greenhouse and field systems, and the production practices that boxwood producers use to produce and ship boxwood nationwide, as well as seasonal changes in temperature and humidity that predominate in the Pacific Northwest (warm dry summer and cool wet winter). Cultures will be grown in petri plates and evaluated for growth and sporulation. Plants will be inoculated and evaluated for the number of plants that become infected and for the amount of disease that develops on each plant. Experiments will be repeated over 2 years. Methods for sampling and boxwood blight will be evaluated for ability to detect infection by the boxwood blight infection and for ease of use by boxwood growers, diagnostic clinics, and agricultural inspectors. Detection methods may include molecular procedures such as enzyme linked immunosorbant assays or polymerase chain reaction, sampling and collection procedures to concentrate inocula, biological or electronic pathogen detection systems (trained dogs or electronic compound detectors), spore traps, or other relevant procedures. Detection methods will be tested for ability to detect pathogen cultures and infected plants in planned experimental plots and in nursery settings.