66 



DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



whole life cycle. Thus the time of hatching of the earliest larvae of 

 the second brood came 21 days ahead of those for the previous year, 

 and the time of hatching of the second-brood larvse extended over an 

 unusually long period of two and a half months. The second-brood 

 larvse were exceptionally abundant, being in some orchards equal in 

 numbers with those of the first brood. In figure 20 a summary is 

 given in a graphical form to illustrate the progress of the development 

 of the codling moth in the course of the whole season of 1911. 



25 30 5 10 15 20 23 3o 5- 10 15 10 25 30 5 10 15 20 25 30 5 10 15 20 25 30 5 10 15 

 JULY AUGUST SEPTEMBER OCTOBER 1 NOV. . 



Fig. 19. — Curves made from band-record experiments in orchards at Pent water, Douglas, and Benton 

 Harbor, Mich., 1911. (Original.) 



WEATHER RECORDS FOR 1909, 1910, AND 1911. 

 Considering the variation in the time of transformation of the cod- 

 ling moth during the three years of observation, it becomes evident 

 that the insect is largely governed by climatic conditions. This is 

 only natural, since phytophagous insects, depending upon the 

 development of their host plants, must to a certain degree be 

 governed by the same phenological laws that govern these plants 

 The earliest codling moths of the spring brood generally appear at a 



