92 N. H. AGR. EXPERIMENT STATION. [Bulletin 171 



No spraying was done in 1912 because of comparative scarcity 

 of adults. 



In 1913 poison bait sprays were again tried on a still larger 

 scale. Precautions were taken as before to safeguard against 

 unwarranted deductions from apparently favorable results. 



The bait used each year contained some form of sweets as the 

 element of attraction. This consisted of sugar, or molasses, or 

 sometimes glucose. The poison employed was arsenate of lead. 

 The amount of sweets and the proportion of poison varied. In 

 no case was a soluble arsenical used. It was believed then and is 

 considered now that the employment of such a material, result- 

 ing invariably in the destruction of all foliage that receives it, 

 must be a drastic remedy of last resort. 



The net results of all these experiments were in essential agree- 

 ment, and may be summarized as follows: Poison bait sprays, 

 as so far devised, have entirely failed to insure protection of the 

 fruit of the sprayed trees from attack by the maggot. In j^art of 

 the experiments there was apparently some improvement of the 

 fruit, especially in isolated trees. This may have resulted from 

 the death of flies because of the sprays; or it mfiy have been 

 due to various other factors. The important point is that no 

 such protection was forthcoming as would be essential if the 

 treatment were to be ranked as an effective means of control. 



Even with 6 to 10 applications in a season, keeping fruit and 

 foliage thoroughly and constantly coated throughout the activity 

 of the flies, the apples often showed abundant egg punctures. One 

 of the worst lots of apples examined in all of the investigation, 

 from the standpoint of the number of egg punctures, was the 

 fruit from a Porter tree that had received seven applications of a 

 poison bait spray. The maximum number of egg punctures ever 

 recorded in a single apple — 46 — was found on this tree. There 

 were many apples on it with 20 or more punctures. The fruit 

 was so thoroughly coated with the spray material that it was 

 necessary to wipe it before counting the punctures. 



The above conclusions should not be taken as asserting that 

 no flies are poisoned by such sprays. Some flies may be. Indeed 

 it may be, as will be noted later, that with ordinary spraying of 

 apple trees with a simple solution of arsenate of lead and water 

 for some other insects, such adults of the Apple Maggot as chance 



