Published March 1936. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
Roses are the most popular perennial flowering plant in the United States, and they grow well in
the Pacific Northwest (PNW). Our climate provides ample rainfall during the peak leaf growth
period, moderate winters that rarely result in freezing damage, and warm, sunny summers for flower
production. Wild roses grow...
The present studies were conducted to better understand the
etiology, epidemiology and potential control of the Phytophthora
stem root rot as it occurs in apple stool beds.
Symptoms of Phytophthora root and stem rot occurred as early
as May and continued to develop throughout the growing season.
Sunken brown-black lesions...
There is considerable variation among rose varieties in susceptibility
to mildew, and as a result of maturation, leaves of most
susceptible varieties become resistant to infection. The nature of
resistance has been sought in various studies involving environmental,
morphological, and physiological factors. An attempt was made in the
An isolate of Coniothyrium obtained from a stem canker on
Nocturne rose from the Botany Department Farm, Corvallis, Oregon
was studied with respect to morphological and cultural characters,
pathogenicity and mineral nutrition. The hyphae of the isolate were
smooth, septate and branched. The hyphal cells averaged 16.37 X
Studies were conducted on pathogenic specialization and
heterothallism in Sphaerotheca pannosa var. rosae, causal agent of
rose powdery mildew.
Methods were developed for isolation and identification of
Sphaerotheca pannosa var. rosae races on rose. Monoconidial isolates were initiated on detached leaves, increased on host plants,
and inoculated to rose cultivars...