July, 1914.] THE APPLE MAGGOT. 91 



a season of abundance of the adults when adjacent early or at- 

 tractive trees have failed to fruit. Yet such fruit, except for the 

 early drops, may mature few larvjE. Thus in spite of heavy in- 

 festation the previous season there may be very few adults about 

 in the year of treatment. 



There are years of comparative scarcity of adults, due to a com- 

 bination of circumstances. Apparent results in such years are 

 apt to be untrustworthy. 



It will be noted that these factors apply particularly to the 

 judgment of results of treatment that appear favorable. If the 

 treatment for the adults gives vnfai'orable results it is of little 

 moment whether the flies came from the trees under treatment 

 or elsewhere; the treatment was in any event unsuccessful in its 

 net results. 



POISON BAIT SPRAYING. 



In South Africa and elsewhere, in the case of the Mediterranean 

 Fruit Fly and some other species, apparently favorable results 

 have been recorded from spraying with a combination of sweets 

 and an arsenical applied as a poison bait for the adult females. 

 The feeding habits and other characteristics of the Mediterranean 

 Fruit Fly are, however, known to be different from those of the 

 Apple Maggot. For example, the former seems noticeably at- 

 tracted to various substances available for baits, including 

 even kerosene; again the adults frequent fallen fruit. 



In the discussion of the response of the adults of the Apple 

 Maggot to baits, and their feeding habits, as detailed earlier in 

 this bulletin, it was stated that there was no noticeable attrac- 

 tion to sweets. Nevertheless it was hoped that the adults 

 might respond to a more wholesale distribution of the bait,, 

 such as would be afforded by suitable spraj-ing. 



With this in view, experiments in poison bait spraying were 

 begun in 1910. These first exj eriirents wore for the most part 

 without sufficient check as to the actual ai>undance of flies in the 

 trees treated. The importance of this factor was not then under- 

 stood. 



In 1911 experiments were continued. Spraying operations 

 were conducted at various points. Account was taken of 

 attendant conditions. Results were based on actual counts of egg 

 punctures. 



