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
present investigation...
The lower Willamette River, located between river mile 4.0
and 26.5, is the most seriously polluted section of the Willamette
River Basin.
Low dissolved oxygen concentrations of 2.0 to 3.0 mg/1 are
observed annually in this section of the river due to the pollutional
loads discharged into it. Waste discharges...