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



RELATION OF CODLING MOTH SPRAYS. 



In the experiments described above, it has been proved that 

 even ten applications of a poison bait spray, keeping the material 

 thoroughly in evidence throughout the season of the adult flies, 

 failed to give protection from attack by the maggot. This being 

 true, it appears to the writer self-evident that the ordinary spray- 

 ing for codling moth will not in itself afford protection. 



The material used in codling moth spraying contains no greater 

 quantity of poison than was employed in the above experiments, 

 and frequently less. Furthermore, the first application for codling 

 moth is made from three to four weeks before the earliest adults 

 of the maggot make their appearance, and the second application, 

 if one is given, is made from two to four weeks before the max- 

 imum emergence of the adults. 



In studies of New Hampshire orchards many were found in 

 which thorough spraying for codling moth was done, yet attack 

 by the maggot on certain trees persisted undiminished, if condi- 

 tions in the matter of susceptible variety and neglect of the drops 

 were favorable to the maggot. 



However, that there is an indirect benefit from ordinary cod- 

 ling moth spraying the writer believes certain; and this effect may 

 be of material help. These results appear to be as follows: 



Apple trees well sprayed for codling moth are presumed to 

 drop their fruit lisss early, less continuously, and in less quantity 

 than unsprayed trees. Such lessening of dropping reduces the 

 opportunity for the maggot to mature and leave the fruit, and 

 thus results in an increased percentage of mortality of the egg 

 and larval stages. The effect of this, after two or three seasons, 

 would be a diminishing amount of infestation. 



Combined with this there may be some killing of adults from 

 chance feeding or drinking at spots where drops of poison persist. 



The part these benefits may play in comparative infestation in 

 various types of orchards will be noted below in a discussion of 

 the effects of general orchard practice. 



POISON TRAP PANS. 



The action of adults in the presence of various substances 

 ofTered them in confinement has been noted earlier in this bul- 

 letin, in the discussion of feeding habits. Reference will be 



