36 



BULLETIN 1235, U. S. DEPARTMENT OF AGRICULTURE. 



there was a high winter mortality, 5,347 worms were secured, more 

 than twice as many as in 1919. The first worms appeared in the 

 bands on July 8, 15 days later than in 1919, and the maximum for 

 the first brood occurred July 20. The number decreased thereafter 

 until August 19, after which it rose, reaching a maximum for the 

 second brood on September 6, as shown in Figure 20. 



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Fig. 20.— Occurrence of codling moth larvae under bands on apple trees at Yakima, 



Wash., 1920. 



In the Walden orchard, 10 trees were again banded, but the 

 orchard had changed owners, and was very thoroughly sprayed in 

 1920, with the result that only 665 worms were secured during the 

 season. This was hardly enough to indicate the maximum occur- 

 rence of the two broods. The maximum number of first-brood 

 worms was collected on July 17, though nearly as many were found 



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Fig. 21.— Occurrence of codling moth larva? under bands on apple 

 trees at Buena, Wash., 1920. 



on July 11, which is 9 days earlier than the maximum at Ya kim a. 

 For the second brood, the maximum was not obtained until September 

 6, the same date as the maximum at Yakima, as shown in Figure 21. 

 A summary of the seasonal history of the codling moth for 1920 is 

 shown in Figure 22. 



