74 N. H. AGR. EXPERIMENT STATION [Bulletin 143 



deposited on the foliage by spraying Avhen the blossoms fall 

 may kill many of the worms which do not enter the apple through 

 the calyx. 



It has usually been recommended to give a second spraying 

 ten days to two Aveeks after the first one, though no ver.y good 

 reason for spraying at this time has ever been advanced. A sec- 

 ond spraying at this time may be advisable for the curculio or 

 with fungicides for various diseases, but there seems to be no 

 reason for spraying at this time against the codling moth. It 

 will be remembered that the eggs of the codling moth hatch about 

 four weeks after the apple blossoms fall. Having poisoned the 

 calyx cavities of the apples by the first spraying after the petals 

 fall to destroy the majority of the larvae which enter the fruit 

 at the calyx, it would seem rational to spray the foliage where 

 the eggs hatch to destroy the young caterpiHars while they are 

 feeding upon it. To do this the spraying would need to be 

 done the last week in June or the first week of July. It will be 

 seen that the time of this spraying is determined by our studies 

 of the life history of the insect. To test the efficiency of spray- 

 ing the last week in June as compared with a second spraying ten 

 days to two weeks after the first, several i)l()ts were sprayed at 

 each of these times and given no other spraying. Other plots 

 were given the first spraying and then the second about the mid- 

 dle of Juue or the last week in June and these were compared. 

 It is evident that much of the spray applied tlie middle of June 

 would adhere until after the eggs hatched, but thai it would 

 pi'ohably not be as efficient as that applied just as they were 

 hatcliiiig. Plots sprayed only the last week in June showed 

 70 per cent, benefit in the control of worminess as compared 

 with 82 per cent. Ijenefit where the first spraying only was given, 

 showing the effectiveness of applying the ])()ison to the foliage 

 when the eggs are hatching. In 1907, with a noi in.il rainfall, a 

 plot sprayed but once, two weeks a Tier Ih ■ l)li!ss(iiiis dropped, 

 gave but 25 per cent, benefit, while one sprayed but once, three 

 to four weeks after the blossoms dropped, or when the eggs were 

 hatching, showed 47 per cent, benefit. In 1!)0S. with l)ut little 

 rain in June, there was but little difference, as the poison applied 

 earlier remained on the foliage. A second spraying given two 

 weeks after the blossoms dropped, in addition to the first, showed 



