New York Agricultural Experiment Station. 293 



country its treatment and control have been the subject of a 

 large number of publications. Unfortunately a number of con- 

 flicting and misleading results have been obtained and pub- 

 lished. As a result, orchardists are often at a loss to know 

 whether the expense and the chances of failure are not too great 

 to warrant undertaking any treatment, or are unable to decide 

 correctly between different methods. We feel justified, there- 

 fore, in adding another chapter on the treatment of this notor- 

 ious pest. In addition it is desirable to record the conditions 

 and results met with in this section of the State (Long Island). 



OBJECT OP TESTS. 



The object of making the following tests was not only to 

 determine the amounts of potassium cyanide that should be 

 used in orchard work, together with its effect on trees and in- 

 sects, but to determine whether it is possible to exterminate this 

 pest over small isolated areas and at same time to simplify and 

 cheapen the method so that orchardists would find fumigation 

 feasible. Incidental to this work were tests on time of chemi- 

 cal action, on kinds of apparatus used, and on cost 



HISTORY OF TESTS. 



During the winter of 1899-1900, about 20 apple, 14 cherry, 201 

 I^each, 6 pear, and 25 plum trees (in the orchard) were fumigated 

 by means of tents. As it was not only impossible to estimate 

 accurately the amount of space enclosed by a tent when placed 

 over a tree, but was also found impracticable to prevent fre- 

 quent leakage of gas from the tents, caused by constant wearing 

 and puncturing by the branches, the work was discontinued until 

 the winter of 1900-1901, at which time folding fumigators hav- 

 ing fixed dimensions were constructed and used. The plums, 

 pears and cherries, which were separated from the main orchard 

 by a high embankment and were distant one-eighth mile, were 

 not treated again; but the apple and peach trees, treated the 

 previous winter, were refumigated. 



