Washington State University

Ornamental Plant Pathology Program

Christmas Tree Research

Postharvest research on christmas trees in Arizona.Nationally, about one-third of all of the Christmas trees produced each year come from the Pacific Northwest. The primary goal of the WSU Puyallup Christmas tree program is to provide growers and retailers with research-based information that creates a high-quality Christmas tree product for consumers. To this end, the program covers two principal areas: disease and pest management and the postharvest quality of cut Christmas trees.

Annosus root rotCurrent disease and pest management research is focused on the development and management of Annosus root rot, the development of effective ways to reduce populations of insects on trees that restrict export markets, and the identification of sources of trees with resistance to common diseases and insect pests such as Phytophthora root rot, current season needle necrosis, Grovesiella canker, spider mites, and twig aphids.

The current focus of the postharvest research program is the identification of sources of different types of true firs that have superior needle retention. A detached branch test has been developed and is being used to study the effect of harvest date on needle retention and identify genetically superior sources of trees. This research is being done in cooperation with scientists and growers in eight states and four foreign countries and trees that have been identified with superior needle retention are being propagated at a number of nurseries.

Contact: Gary Chastagner, 253-445-4528 | WSU Puyallup Research & Extension Center,2606 West Pioneer, Puyallup, WA, 98371-4998 USA