SPRAYING EXPERIMENTS. 



59« 



Table I. Effect of spraying on cedar rust. 



Dates of Spraying. 



Apr. 27, May 28 



Apr. 27, May 9, 



May 9, May 28 



Apr. 27, May 9, May 28 



ZZ'. '^ZZZ. May 28 



May 9, May 28 



Apr. 27, May 9, May 28 



Apr. 26, 



May 23 



Apr. 26, May 23 



Apr. 26, May 23 



May 7, May 23 



Apr. 26, May 7, May 23 



Average 



number of 



rust spots- 



per rusted 



leaf. 



1.4 

 1.6 

 1.7 

 1.0 

 1.0 

 3.4 

 2.0 

 2.0 

 1.5 

 2.4 

 2.3 

 2.5 

 2.7 

 2.6 

 2.5 

 1.6 

 1.5 



1 Some distance from cedar trees. 



2 Close to diseased cedar trees. 



From the above table it will be seen that a tree sprayed late 

 in April and not again sprayed showed practically as much rust 

 as unsprayed trees. Moreover, trees given the three sprayings 

 were, as a rule, no freer from rust than trees which received 

 only the two later sprayings. This indicates that the early 

 sprayings had little, almost no, effect in keeping the foliage of 

 apple trees free from rust. The third spraying late in May, 

 gave somewhat better results than the first spraying, though it 

 came too late to control the rust well. With Wealthy apples al- 

 most surrounded by cedar trees, one spraying, on May 28, re- 

 duced the number of rusted leaves by about one third and the 

 number of rust spots by two thirds, while in case of Jonathan 

 apples not close to cedar trees a single spraying on May 23 did 

 not appreciably affect the amount 'of rust. In fact, Jonathan 

 trees sprayed twice, April 22 and again May 23, showed practi- 

 cally as much rust as unsprayed trees. The second spraying, May 

 7 and 9, however, gave very satisfactory results in almost every 

 case. While it happened that no tree was given this early May 

 spraying alone, yet practically every tree given this spraying, 



