Pruning of weakened twigs is recommended for wood injured by the cicada. If treehoppers are a pest, clean cultivation will help. Cover crops of cowpeas or clovers should not be planted. In preliminary tests two or three applications of tetraethyl pyrophosphate (20 percent), 3/4 pint per 100 gallons of water, have given promising results in controlling the periodical cicada. The first application should be made after the cicadas appear and the others as needed to prevent damage.
Observations on Effects of Low Temperatures in Winter 1949-1950 on
Walnuts and Filberts in Oregon and Washington
JOHN H. PAINTER
Horticulturist, United States Department of Agriculture, Agricultural
Research Administration, Bureau of Plant Industry, Soils, and
Agricultural Engineering, Oregon State College, Corvallis, Oregon
In western Oregon and Washington, where the Japan Current is supposed to keep the winter temperatures moderate, something happens every now and then and we get really severe winters. We can't blame it on the "A" bomb because we had severe winter injury in 1919 and 1935 long before the "A" bomb.
The last two winters have been exceptionally cold, but this past winter of 1949-1950 was much more severe than the previous one.
In 1948-1949, the cold came rather suddenly in the latter part of December. In the past winter, 1949-1950, the real cold came on January 30, with temperatures ranging from 10 to 30 degrees below zero F. Most official temperatures were higher; but at Corvallis the official temperatures were taken at least 60 feet above the ground level, on the roof of the Agricultural Building, which is over a steam-heated building and is old enough to be not very well insulated. This cold continued in somewhat modified form for a week.
During the previous winter the lowest temperature recorded in the nut growing areas was about 10 to 11 degrees above zero F., and the severe cold lasted for only a couple of days.
In both winters the ground was fairly well covered with snow, but with considerably more snow this past winter than the previous winter.
No apparent damage to Persian walnuts was observed as a result of the cold in the 1948-1949 winter, but in certain low-lying areas catkins of Barcelona and Daviana filberts were killed, especially those of the latter. Considerable dieback of filberts occurred; but during the following growing season recovery was effected and at the end of the summer very little evidence of winter injury was visible.