April, ’24] 
PARROTT: SPRAY INJURIES 
267 
Vice-President S. B. Fracker: A paper will now be presented by 
Mr. P. J. Parrott. 
i 
SOME SIDE LIGHTS ON SPRAY INJURIES TO APPLE 
FRUITS AND FOLIAGE 
By P. J. Parrott, Geneva , N. Y. 
Abstract 
Because of the danger of injury to apple foliage and fruits from lime-sulfur, ex¬ 
periments were undertaken to determine the value of hydrated lime, calcium case¬ 
inate and glue in reducing the injurious properties of this spray as well as to ascertain 
the utility of various sulfur and copper dusts and sprays as possible substitutes for 
lime-sulfur for summer applications. This report considers only the effect of the 
different materials on the foliage and fruit of apples. All the spray and dust mix¬ 
tures affected to some degree the surfaces of apple fruits. “Sun scald” or “spray 
burn” was the most conspicuous type of injury and was common in all of the plats re¬ 
ceiving applications of sulfur either as lime-sulfur solution or flowers of sulfur, or 
sulfur flour applied as a dust. Russeting varied in intensity with the different treat¬ 
ments. Injuries to foliage were largely confined to plats sprayed with lime-sulfur 
solution. The addition of calcium caseinate, glue, and lime hydrate reduced to some 
extent injuries to both fruits and foliage, but they did not prevent important injury 
to foliage in some instances. 
During recent years much interest has been aroused relative to the 
action of spray and dust mixtures on the quality of fruit as well as on the 
productive capacity of orchard trees, Advocates of dusting have 
pointed out that, generally speaking, dust preparations are more safe to 
foliage and fruit than certain common spray mixtures. 
In spite of the fact that much can be said in favor of lime-sulfur for the 
treatment of both apples and pears for certain applications, it is generally 
recognized that this spray may injure foliage and, so far, there is very 
little definite information relative to the conditions that favor important 
damage, or regarding means of controlling its injurious properties and 
thus render it more safe. 
Injuries by lime-sulfur vary greatly in kind as well as in degree. A 
very common form of injury is browning or “burning” of the tips and 
margins of the leaves. This may T involve large areas of the leaves of a 
considerable proportion of the foliage and is frequently attended with 
premature defoliation of varying extent. In spraying trees for pear 
psylla this type of injury may be severe, and it is a question if in the 
long run applications do not cause more damage than the pest which 
prompted the treatment. Even tho the leaves may reveal no serious 
discoloration, apple trees sprayed repeatedly during the growing season 
may show very characteristic differences from unspraved trees or trees 
