biology and control of the Douglas-fir needle midge in Christmas trees
By: K.J. West, J.D. DeAngelis, and B. Simko.
Contributors: DeAngelis, Jack D.; Simko, B. C.; Oregon State University. Extension Service.
Series: EC / Oregon State University Extension Service -- 1373.; Extension circular (Oregon State University. Extension Service) -- 1373.
Publisher: Oregon State University Extension Service
Published: 1991
Place of publication: Corvallis, Or
Language: eng
Subjects: Christmas trees -- Diseases and pests -- Control -- Oregon.; Contarinia -- Control -- Oregon.
Notes: Title from caption.

"April 1991".