December, 1909.] THE CODLlxr, MorrT. 71 



fully two-thirds of the picked fruit w liitli shows the work of the 

 codling moth has been affected by the second brood, which have 

 maiTi'd the surface or eaten around the calyx, and only about 

 one-third of those wormy show the characteristic work of the 

 first brood. Indeed, the bulk of the apples attacked by the first 

 brood fall to the ground as windfalls, and thus the damage done 

 by it usually escapes notice. That so large a portion of the 

 injury to picked fruit is due to the second generation of larviE, 

 when so small a percentage of the first generation transforms, 

 seems rather remarkable. But if four larvas in 100 of the first 

 generation transformed to two pairs of moths they w'ould lay 

 enough eggs to produce as many larvre as in the first generation, 

 so that it is easily seen how the small percentage transforming 

 can give rise to so much injury. ]\Iost of the larvse of the second 

 generation doubtless become full-grown, as young larvifi placed 

 on apples September 5. 1906, were full grown and made cocoons 

 on October 10. A number of half grown larva^, possibly 20 

 per cent., are always found in cocoons in late fall or winter. 

 These have always failed to transform the next spring, indicat- 

 ing that many of the larvae of the second generation are over- 

 taken by cold weather before becoming full grown. 



II. EXPERIMENTS IN SPRAYING. 



Experiments in spraying for the control of the codling moth 

 were conducted in 1906, 1907 and 1908 to determine the follow- 

 ing points: — 



1. The relative value of different insecticides. 



2. The amount of insecticide most profitable. 



3. The best time or times to spray. 



4. The best method of spraying. 



5. How the spray kills the larvje. 



6. Effect of spraying on the proportion of dropped and picked 

 fruits. 



These experiments were carried on on a large scale and were 

 so arranged that by comparison of the different plots definite 

 conclu.sions could be drawn. They were located in ten different 

 orchards at Durham, Greenland. Hancock, Walpole, Pitt-sfiold 



