46 EXPERIMENT STATION. [Jan. 



SPRAYING INJURIES. 



BY G. E. STONE. 



In recent years injury from spraying has become more com- 

 mon ; at least, it appears to be more noticeable than formerly. 

 This injury is more prevalent some seasons than others, and it 

 is known that certain crops can be treated at one time without 

 being injured and at other times precisely the same treatment 

 may be given with bad results. 



The causes underlying injury from spraying are complex and 

 require attention from the best-equipi>ed investigator. Already 

 enough is known in some special cases concerning the nature of 

 the injury to explain its occurrence at one time and not another. 

 It is also well known that some plants are more susceptible to 

 injury from spraying or fumigation than others, a wide range 

 of susceptibility existing in plants. 



Investigations have shown that meteorological conditions have 

 an important bearing on the problem, but the data which have 

 been collected are not sufficient, either in kind or quantity, for 

 practical use. 



Spraying injury to fruit and foliage has been noticeable the 

 past season, especially on apple foliage. The fruit has also 

 been injured to quite an extent by Bordeaux mixture, which 

 causes the so-called " russeting " of the fruit. 



Some cases have come to our notice during the past year of 

 burning of foliage by arsenate of lead, and our attention was 

 called in one case to the heavy loss of foliage on plum trees, due 

 to spraying with this poison. It is well known that when spray- 

 ing mixtures are not carefully prepared they are likely to cause 

 burning, and in some of the cases observed by us it is not un- 

 likely that the chemical nature of the arsenate of lead may have 

 been responsible for the burning. A number of firms are now 

 putting this on the market, and it is presumable that their 



