274 THE MONTHLY BULLETIN. 



COUNTY COMMISSIONERS' DEPARTMENT. 



THE MISUSE OF THE DISTILLATE OIL MECHANICAL 



MIXTURE. 



By A. A. Brock^ County Horticultural Commissioner, Ventura, Cal. 



The inspectors' reports for Ventura County showed the necessity for 

 spraying a large acreage of apricots in the autumn of 1914. At the 

 very beginning of the season it was seen that the acreage to be sprayed 

 was so hirge that the work could not be handled with the available 

 machines. Several new machines were purchased and later more were 

 rented, our desire being to have the spraying done on the block system. 

 In doing the work in this way it was found necessary to use inexpe- 

 rienced men. Most of them did the work well, but some mistakes were 

 made. I will endeavor to summarize those that have been called to my 

 attention by the inspectors and orchardists. A distillate oil chemical 

 mixture was used in the proportions of: water, 200 gallons; caustic soda 

 (95%), 7 lbs.; distillate (28 degrees Baume), 12 gallons. 



In some of the groves it was noticed that the spraying had not 

 been thorough, one side of a tree having been drenched, while the other 

 was practically untouched. In some cases where young trees newly 

 planted had been sprayed, it was found that almost as much material 

 was used as on the older trees. Several of these were killed outright 

 and on the older trees large limbs were killed, in one case an entire 

 tree being completely destroyed. Besides, where the spray material had 

 been used on citrus trees and palms, much injury resulted. The killing 

 of the trees growing in yards can be attributed largely to s^^raying 

 with the distillate remaining in the tank after previously treating an 

 orchard, and without proper agitation ; this resulted in applying almost 

 pure distillate. 



To avoid such ill effects as we have witnessed this season, there are 

 several important facts that should be remembered : Thoroughly agitate 

 the mixture before beginning to spray ; after stopping to repair or move 

 the tank from one field to another before the tank is empty, do not start 

 spraying until the material has been agitated from five to ten minutes ; 

 material left in the hose should be emptied before beginning to use a 

 new tankful or after stops. Another point to be remembered is that 

 the distillate oil mechanical mixture, such as is used for dormant spray- 

 ing, should not be applied to trees other than deciduous, unless the 

 strength of the spray is reduced and the spray kept thoroughly agitated. 

 For the best results in spraying apricot trees, 10 to 12 gallons of the 

 mixture should be applied to a medium sized tree. This should be uni- 

 formly distributed over the surface of the trees, so that every liml) 

 and twiii' is covered. 



