New York Agricultural Experiment Station. 331 



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 plume 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 4| 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. 



