New York AGRICULTURAL EXPERIMENT STATION. aor 
the applications uniform. The spray should be applied until the 
trees begin to drip slightly. 
Caution—Peach and Japan plum trees are more liable to 
injury by crude petroleum than either European plums or pears 
and apples. It is also to be borne in mind that the full extent 
of the effect of the oil on the tree is not always apparent the first 
season—but may require a second season to show the full extent 
of the injury if there is any. 
Whale-oil soap.—Whale-oil soap is one of the safest insecticides 
that can be depended upon to kill the scale. A caustic soda soap 
is preferable to a caustic potash soap. Although the price fluct- 
uates somewhat it can usually be obtained in 100 pound lots at 
about 43 cts. a pound. 
The soap should be dissolved in hot water using two pounds 
to the gallon, and should be applied to the trees as hot as 
possible. The treatment should be made during the winter. 
