THE CODLING MOTH IN THE YAKIMA VALLEY. 



57 



were somewhat below normal, and the precipitation was relatively- 

 heavy. The early part of June was cool, but the rest of the summer 

 was unusually warm. Of the 72 days in the period from June 21 to 

 August 31, inclusive, 38 days had maximum temperatures of 90° F. 

 or over. The apple trees were in full bloom April 15 to 20. 



Figure 34 gives a summary of the stages in the life history of the 

 codling moth that were chiefly studied in 1915. The maximum 

 pupation occurred during the warm weather in April and the maxi- 

 mum emergence of spring-brood moths just one month later. Of 144 

 pupae observed, the average pupal period was 30.44 days. 



No further studies of the codling moth were made until late in June. 

 Newly hatched larvae had been first noted entering the fruit on trees 

 in the laboratory yard on May 29, and on June 27 the mature larvae 

 were beginning to leave the fruit. On this date 226 wormy apples 

 were collected to secure material for further observations. 



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Fig. 34.— Partial seasonal history of the codling moth at Wenatehee, Wash., 1915 and 1916. 



Of the 179 first-brood larvae observed, the average cocooning period 

 was 6.82 days. Pupation began July 3, as shown in Figure 34, and 

 continued until August 9, with a maximum on July 21. The average 

 pupal period of these first-brood individuals was 11.87 days. Moths 

 began emerging from them on July 13 and continued until August 21, 

 with a maximum on August 1. 



Larvae of the second generation began leaving the fruit on August 

 24, reached a maximum on September 4, and continued to leave the 

 fruit until October 6. No evidence of a third generation was 

 obtained. 



In 1916, the season was later than in 1915, but little warm weather 

 being experienced until the second week in June, when it suddenly 

 became hot, temperatures going above 90° F. on June 13 to 17 

 inclusive, and above 100° F. on the last two days of this period. 

 This hot weather was followed by two weeks of abnormally cool, 



