The effect of tree nitrogen on pear psylla, Psylla pyricola Foerster
By: by Douglas Goode Pfeiffer.
Published: 1982
Language: eng
Number of pages: 80
Subjects: Psylla.; Nitrogen -- Physiological effect.; Pear -- Diseases and pests.
Notes: Typescript.

Thesis (Ph. D.)--Washington State University, 1982.

Includes bibliographies.

WSU:Another copy on microfilm, no. 6257.

WSU:"Department of Entomology."