April, ’24] 
PARROTT: SPRAY INJURIES 
273 
was less than that of lime-sulfur. No difference was observed in the 
action of sublimed flowers of sulfur or flour sulfur. The addition of lime 
seemed to aggravate the injury. These sprays differed markedly from 
lime-sulfur in that they caused no injury to the foliage. 
Sulfur applied as a dust produced both russeting and “spray bum” 
but both were very much less in evidence than in the plats sprayed with 
lime-sulfur. The general appearance of the fruit was superior to that 
treated with “wettable sulfur” or lime-sulfur. 
The copper dusts caused no spray burn. Heavy applications pro¬ 
duced severe russeting which was accompanied by cracking of the 
surfaces of the apples. The apples from trees receiving light dosages 
lacked the luster of fruits dusted with sulfur or sprayed with 
“wettable sulfur ” 
In the treatment of apples with dusts the danger of injury to fruit and 
foliage is not as great as with spraying mixtures. The undesirability of 
applying copper mixtures in the calyx application, which had long been 
recognized, seems to be corroborated by these tests. From the stand¬ 
point of pest control, as well as safety to plants, much is to be said in 
favor of frequent applications of light dosages of the different dusts as 
against heavy dosages at wider intervals. 
The data from this series of experiments suggest no satisfactory spray 
as a substitute for lime-sulfur, altho the “wettable sulfur” mixtures 
should be given further trial. Likewise little light has been shed 
relative to methods of controlling injury by lime-sulfur. Under the 
circumstances all the grower can do is to follow the usual instructions 
such as, apply minimum amount of spray necessary to wet foliage; 
avoid coarse, drenching sprays; treat trees systematically according to 
schedule to combat both insects and diseases and thus prevent rupturing 
of foliage which facilitates spray injuries; add lead arsenate to lime- 
sulfur when ready to spray, and do not allow mixture to stand long 
before applying; employ calcium caseinate or lime hydrate to prevent or 
neutralize respectively, free arsenic formed by the reaction between 
lime-sulfur and lead arsenate; abstain from .spraying during periods of 
high temperatures, etc. 
Some varieties, such as Greenings, McIntosh and Ben Davis, have 
proved more susceptible to burning of foliage than other sorts; and 
Greening apples especially have generally been less free of spray scald 
and russeting than Rome apples, the injuries of different types varying 
considerably according to seasonal conditions and character of spraying 
