APPLE POWDERY MILDEW AND ITS CONTROL. 19 



THIRD APPLICATION. 



The third application should be made three weeks after the second, 

 and the insecticide regularly employed at that time should be added 

 to the spray mixture, as directed under " General formula for the 

 spray mixture," on page 17. 



FOURTH APPLICATION. 



The fourth application should be made three weeks after the third, 

 and the insecticides commonly employed at that time should be added 

 to the spray mixture, as directed under " General formula for the 

 spray mixture," on page 17. 



SPRAYING METHODS. 



In the spraying schedule here recommended it will be noted that 

 the intervals between the applications are never greater than three 

 weeks. In order to avoid any risk of causing sulphur injury in the 

 form of fruit dropping it is very important that strict attention be 

 given to the timing of the application, and, if necessary, the intervals 

 should be made less rather than greater than three weeks. Obvi- 

 ously the weak dosage of iron-sulphid mixture recommended will not 

 bring as marked and rapid mildew control as a stronger one would; 

 but if the spraying is consistently and regularly done good .results 

 will surely be obtained, and it has been a noticeable fact that when a 

 portion of an orchard is given this treatment for one year that por- 

 tion, as compared with the remainder of the orchard, has shown de- 

 cided improvement when the trees leaf out the following spring. 

 Such an effect is probably partly physiologic and partly the result of 

 mildew control, and its bearing on the general condition of the trees 

 is evident. 



Too much can not be said regarding the value and importance of 

 thoroughness in spraying. A very large proportion of the men who 

 handle the spray rods have, to say the least, a very inadequate con- 

 ception of a satisfactory job of spraying, and when it is remembered 

 that every leaf is susceptible of mildew attack, the importance of 

 taking time to do a thorough job should be apparent. 



Equipment is an important factor in good work. While prac- 

 tically all the spraying in the Pajaro Valley is done with power 

 outfits it is entirely out of the question to spray a hundred-acre 

 orchard with a single machine and finish the work in anything like 

 schedule time. Attention has been called to the great number of 

 twig infections in the upper parts of the trees, which means that 

 care should be taken to spray the tops thoroughly. Spray rigs hav- 

 ing towers are not used in the Pajaro Valley, and it has been neces- 

 sary to depend upon long spray rods for reaching the tops of old 



