32 BULLETIN 959, U. S; DEPARTMENT OF AGRICULTURE. 



Table 21. — Spraying schedules for the codling moth in the Grand Valley of Colorado. 





Spray 

 appli- 

 ca- 

 tion. 



Time of application. 



Applications. 



Application. 



I. 



Light in- 

 festation 

 and with 

 varieties 

 on which 

 the codling 

 moth is 

 not diffi- 

 cult to 

 contrpl. 



n. 



Medium 

 infestation 

 and with 

 varieties 

 on which 

 the codling 

 moth is 

 moder- 

 ately diffi- 

 cult to 

 control. 



III. 



Heavy in- 

 festation 

 and with 

 varieties 

 on which 

 the codUng 

 moth is 

 difficult 



to 

 control. 



Caljrs spray 



Cover spray, first 

 brood. 



Do 



A. 



B. 



C. 



D. 



E. 

 F. 



G. 



H. 



I. 



Begin when 90 per cent petals have 

 dropped and finish before calyces 

 close. 



3 to 4 weeks after A, just previous to 

 time when first-brood larvse begin to 

 hatch. 



10 to 12 days after B, just previous to 

 hatching of first-brood larvse in large 

 numbers. 



15 to 17 days after B, just previous to 

 hatching of first-brood larvse in 

 maximum numbers. 



10 to 12 days after C, for late hatching 

 first-brood larvse. 



9 to 10 weeks after A, just previous to 

 time when second-brood larva; begin 

 to hatch. 



24 to 26 days after F, just previous to 

 hatching of second-brood larvse in 

 large numbers. 



34 to 38 days after F, just previous to 

 hatching of second-brood larva; in 

 maximum numbers and for protec- 

 tion against third-brood larvse. 



15 to 17 days after G, for late hatching 

 second-brood larvse and for protec- 

 tion against third-brood larvse. 



First 



Second 



First 



Second 



Third 



Ft)urth.... 

 Fifth 



First. 



Second. 



Third. 



Do 



Third 





Do 



Fourth. 



Cover spray, second 

 brood. 



Do 



Fourth.... 



Fifth. 

 Sixth. 



Cover spray, second 

 and third broods. 



Do 



Fifth 



Sixth..... 



Seventh. 











From the foregoing schedules it will be seen that the first or calyx 

 treatment is given in each schedule and that it should be started when 

 about 90 per cent of the petals have dropped, and should be finished 

 before the calyces close. The object of this application is merely to 

 fill the calyx or blossom end of the fruit so that the worms that 

 attempt to enter by way of the calyx will be killed by the poison 

 lodged therein. Any spray applied after the calyx cups "have closed 

 will have no value in checking calyx worms. This application should 

 be very thorough, and, for the sake of speed, it is advisable to use a 

 spray under a pressure of about 225 pounds. 



Schedule I consists of four cover sprays, the first of which should be 

 applied three to four weeks after the calyx application, just previous 

 to the time when the first-brood larvse begin to hatch. This appli- 

 cation will serve to coat the young fruit and foliage with poison as a 

 protection against the early hatching worms. The second cover spray 

 for the first brood should be applied 15 to 17 days later, just before the 

 first-brood larvse hatch in maximum numbers. The first cover spray 

 for the second brood should be made 9 to 10 weeks after the calyx 

 treatment, just prior to the time when the second-brood larvae begin 



