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CIRCULAR 2 7 0, LV S. DEPARTMENT OF AGRICULTURE 



The calyx spray is applied for the purpose of depositing enough 

 poison in the calyx cup to kill all the worms that attempt to enter the 



fruit at that place. Since 

 more than half of all the 

 worms may attempt to 

 enter the fruit through the 

 calyx, it is very important 

 that the calyx spray be ap- 

 plied thoroughly. Spray- 

 ing should begin as soon as 

 most of the petals have 

 dropped (fig. 5, A) and 

 should be completed before 

 many of the calyx cups 

 have closed (fig. 5, B). 



In certain favored locali- 

 ties, particularly along the 

 coast, spraying may not be 

 necessary at all, or perhaps 

 the calyx spray will suffice. 

 In most of the region, how- 

 ever, one or more cover 

 sprays are required, the 

 number depending on the 

 altitude, climate, degree of 

 codling - moth infestation, 

 and other factors. In the 

 great majority of apple 

 orchards in the Pacific 

 Northwest five or six cover 

 sprays should be used, three 

 or four for the first brood 

 and two for the second 

 brood. (See spraying 



schedules, p. 75.) 



It is very important that 

 the first-brood sprays be 

 applied thoroughly and at 

 the proper time, to elimi- 

 nate as far as possible the 

 first brood of worms. The 

 first cover spray should be 

 applied from 8 to 21 days 

 after the calyx spray, de- 

 pending on temperature, 

 and is the most difficult to 

 time properly. However, 

 it may be timed by observ- 

 ing the numbers of moths 

 entering baits placed in the 

 trees (p. 76), and also the 

 .temperatures registered at 8 p. m. by a thermometer hung in the 

 orchard away from the buildings. These observations should begin 

 as soon as the trees are in bloom. When two or more consecutive 



Figure 5. — A, Apple blossoms from which the 

 petals have just fallen; the right stage at 

 which to apply the calyx spray for the codling 

 moth; B, too far advanced for calyx spray. 



