THE OLIVE INSECTS OF CALIFORNIA 47 



The miscible oils cannot be satisfactorily prepared at home and 

 should be purchased from a reliable manufacturer or dealer and used 

 according to the directions that accompany them. 



The oil emulsions, distillate-caustic soda-water mixture and the 

 miscible oils often separate in the spray tank if the water contains 

 much mineral matter and should be applied only with a good power 



Fig. 3. The ivy or oleander scale, Aspidiotus hederae (Vail.), and its work on the 

 fruit of the olive. (Original.) 



(Photo by Div. Sci. Illust., Univ. Calif.) 



machine with a forceful agitator, which must be kept going during 

 the entire process of application to avoid oil injury to the trees. 



The soap powders are a revival in a somewhat different form of an 

 old spraying material (soap) and in the present form are compara- 

 tively new in spraying work and are meeting with much favor because 

 of their comparatively cheapness, ease of handling and efficiency. 

 They are put up in barrels, and are ready to add directly to the 

 water in the spray tank, dissolving readily in cold water with a small 

 amount of stirring or agitation. The average dose is about one pound 

 to every five gallons of water. 



