426 CONTROLLING INSECTS AND PLANT DISEASES 



Paris green, arsenate of lead, or other poison may be mixed 

 with this to poison insects at the same time that the Bordeaux 

 mixture is preventing disease. 



A few examples for which this combined spray would be 

 used are: 



Apple scab and coddling moth. 

 Potato blight and potato beetle. 

 Brown rot of peach and curculio. 

 Tomato "wilt" and tomato worm. 



PRINCIPLES OF SPRAYING 



Never spray without knowning what you are spraying for. 

 Be sure that the application is made at the most suitable time 



FIQ. 295. This four-row sprayer is operated by chain gear on the axle. It is suitable for 

 spraying potatoes, cabbage, and other truck crops. (Courtesy Osborn Co.) 



to accomplish its purpose. Do not wait until the calyx is closed 

 before spraying for controlling codling moth. Do not wait until 

 the leaves are nearly all destroyed before fighting a leaf -eat ing 

 insect, such as canker worm, or potato beetles (Fig. 295). 



Spraying is always more effective if the work is done on a 

 bright, calm day (Fig. 296). The material should dry on the sur- 

 face soon after its application. 



Be sure that all parts of the plants are touched with the spray, 

 as the unsprayed parts may feed the insects and defeat your main 

 purpose. 



Learn of the horticulturist at your state experiment station 



