82 



to reduce to negligible amount the number of cluster apples, 

 v,hich are principally the work of the rosy aphis. 



And noAV as to control measures ! During the progress 

 (I their life cycle the apple aphides are at various periods 

 if.ore or less vulnerable to applications of spraying mix- 

 tures. As a result several methods of spraying have been 

 developed which are based on susceptibilities of certain 

 stages of the insects to particular insecticides. The chief 

 points of attack in the life of the aphides to whicli most at- 

 tention has been directed are: 



1. In the winter or egg stage. 



2. As eggs hatch and the lice are assembled on the 

 green ends of the growing- buds. 



3. At time of maturing of stem-mothers and first ap- 

 pearance of their young. 



4. At time of appearance of fall migrants and- egg- 

 hiying females cm apple trees. 



The problem of controlling the aphides by spraying di- 

 rected against any of the foregoing stages has proven ex- 

 ceedingly ditficult. In order to secure data applicable to 

 New York conditions the Geneva Station has been and is 

 conducting a series of spraying experiments in apple or- 

 chards in various parts of the state. The work so far points 

 to the destruction of the aphides on the expanding buds as 

 the most important step to avoid injuries by tho.-e pests, 



From a practical as well as a scientific standpoint this 

 method of control requires additional study and experi- 

 mental effort. For this reason it has seemed important to 

 those who have had the planning of these experiments that 

 they continue over a series of years in order to eliminate as 

 far as possible inaccuracies due to unknown and uncontrol- 

 able conditions and thus secure accuracy of results from 

 which conclusions may be drawn. The experiments have 

 now run for two years, and the work of the past season has 

 strongly corroborated the position we have taken. The 

 possibilities of combating the rosy aphis by this treatment 

 are indicated in the accompanying table, which summarizes 



