14 



MASS. EXPERIMENT STATION BULLETIN 207. 



A general study of the results obtained by spraying the cherry indicates 

 that this tree is more sensitive to high temperatures where H is low than 

 the apple, while at high humidity with low T it is, on the whole, more re- 

 sistant. In both fruits the general agreement in each case of the various 

 acid pastes and the noticeable way in which the neutral arsenate stands 

 apart from the others are very marked. 



Plum — Safety Lines for Spraying. 

 AB, clear weather; CD, cloudy v/eather. 



Fig. 13. — Pure acid lead arsenate 

 paste. 



Fig. 14. — Commercial acid lead 

 arsenate paste. 



Fig. 15. — Commercial acid lead 

 arsenate powder. 



Fig. 16. — Pure neutral lead arsenate 

 paste. 



Plum. ■ — The facts obtained here apply only to the Bradshaw plum. 

 The results of the tests of pure acid lead arsenate paste in clear and cloudy 

 weather are given in Fig. 13, and show at once that the resistance of this 

 tree to arsenical sprays is much less than that of the cherry. An addi- 



