ORCHARD INSECTS OF THE PACIFIC NORTHWEsi 5 



The fruit grower should therefore study weather conditions as well as 

 conditions in his orchard and plan his spraying schedule accordingly . 



CONTROL 



Spraying the fruit to protect it from the codling moth is so effective 

 that this method of control is far more important than all the other 

 methods put together. Maximum efficiency is not so easily at- 

 tained in spraying for the codling moth as in spraying for other pests, 

 because more sprays are necessary, and the time of application is more 

 important, since a spray applied at the wrong time may be largely 

 wasted and the fruit left unprotected when large numbers of worms 

 are hatching. Other orchard operations, such as irrigating, culti- 

 vating, thinning, and the handling of alfalfa cover crops, should not 

 be allowed to interfere with the spray schedule. It is more difficult to 

 determine the proper time for applying codling-moth sprays than for 

 applying any of the other sprays used by the fruit growers of the 

 Pacific Northwest, as the time differs from year to year. 



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 applied thoroughly. Spraying 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 localities, particularly along the coast, spraying 

 may not be necessary at all, or perhaps the calyx spray will suffice. 

 In most of the region, however, 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 5 cover sprays should be used, 3 for 

 the first brood and 2 for the second brood. (See spraying schedules, 

 p. 71.) 



It is very important that the first-brood sprays be applied thor- 

 oughly and at the proper time, in order to eliminate as far as possible 

 the first brood of worms. The first cover spray should be applied 2 

 to 3 weeks after the calyx spray, and is the most difficult to time 

 properly. However, it may be timed by observing the numbers of 

 moths entering baits placed in the trees (p. 72), and also the tem- 

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

 away from the buildings. These observations should begin as soon 

 as the calyx spray is completed. When two or more consecutive 

 nights occur with temperatures of about 60° F. or higher at 8 p.m., 

 after the appearance of numbers of moths in the baits, the cover 

 spray should be completed within 10 days. In most localities two 

 or more cover sprays are necessary for the first brood, and these 

 should be applied at intervals of 10 days or 2 weeks, using the baits 

 as indicators of the activity of the moths. 



The second-brood worms begin to hatch about 8 or 10 weeks after 

 the petals have fallen. The influx of increasing numbers of moths 

 in the baits during July will give an accurate indication of the need for 

 second-brood spraying, which should begin as soon as a definite 

 increase occurs. In moderately infested orchards 1 more cover spray 

 about 4 w^eeks later is sufficient, but in many cases 2 more sprays, at 

 intervals of 3 weeks, are needed. There is seldom any use in spraying 

 after the middle of August. 



