498 ANNUAL REPORT OF THE Off. Doc. 



THE) FUNDAMENTALS OF SPRAYING. 



By Ahxold V. Stubenhal'CU, B. S., M. S. a., Instructor in Horticulture in the University of Illinois 

 and Assistant in Horticulture at the Illinois Experiment Station. 



INTRODUCTOKY. 



Although the literature on spraying has become extensive since 

 the introduction of the practice of treating trees and plants with in- 

 secticides and fungicides, there still remains much to be told to the 

 ordinary grower of crops. In general, it may be said that the matter 

 put forth has not been detailed enough. While the subject has been 

 fnlly exploited so far as the desirability of spraying and the kinds of 

 substances and compounds to be used are concerned, the many little 

 points and details which go so far to make successful results pos- 

 sible have for the most part been overlooked in the effort to accomp- 

 lish greater things. It will be the purpose of this bulletin to take up 

 and consider the fundamentally important details of spraying, and 

 attempt to exi)lain the principles involved, so as to render it possible 

 for the growers to think and act for themselves; thus enabling Ihem 

 to proceed intelligently and effectively in this important line of hor- 

 ticultural work. 



Spraying is perhaps the most expensive of our orchard practices. 

 For that reason it is very likely the most generally slighted of all 

 horticultural operations. It is, on the other hand, the most exacting 

 in its requirements. For without the most intelligent and painstak- 

 ing care in every detail of the work, the etTorts may lead not only 

 to ineffective but even to negative results. 



Importance of Timely Work. 



In the first jjlace the ajjplication must be timely. It will not do 

 to put off spraying work until some other farm duties have been 

 doue, and then go out and squirt around in a hit and miss sort of 

 fashion. The time when an insect or fungus can be successfully 

 combated is, in m.ost cases, exceedingly short. Often a difference of 

 a (^ay or two is sufficient to change success into failure. Thus in the 

 case of codling moth, for example, it is impossible to reach the worm 

 after it has gotten well into the fruit. As its first efforts are directed 

 toward® burrowing into the fruit, it is essential to have a poisonous 

 dose on hand as soon as the worm is hatched. Moreover, *Slinger- 



•Cornell UnlverBlty Experiment Station Bull etln 142, p. 31. 



