ORCHARD INSECTS OF THE PACIFIC NORTHWEST 7 



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 8 or 10 days. In most localities two or 

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

 be applied at intervals of about 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 weeks later is sufficient, but in many cases 2 or more addi- 

 tional sprays, at intervals of 2 or 3 weeks, are needed. 



Pears ordinarily do not become so wormy as apples, particularly 

 when interplanted with them, the moths showing a preference for the 

 apples. ' In solid plantings of pears, the fruit often becomes decidedly 

 wormy unless properly sprayed. A calyx spray should always be 

 applied, but as the pear calyces do not close rapidly, there is more time 

 in which to apply this spray to pears than to apples. Following the 

 calyx spray, a cover spray should be given about 4 weeks after the 

 petals have dropped. Where pears are interplanted with apples, 

 they may be sprayed at the same time as the apples. In the warmer 

 sections it is necessary to apply further cover sprays according to the 

 seriousness of the infestation. Bartlett or other early varieties should 

 not be sprayed after the end of July, as they are usually harvested 

 in August. If only one spray is needed, it may be applied at the time 

 of the first cover spray for apples, and will act as a combined calyx 

 and cover spray, because most of the calyx cups in pears remain open 

 until after this time. If experience has indicated that this one spray 

 is insufficient, a calyx spray should be applied earlier in the season, 

 because pears are more subject to calyx worms than apples and need 

 more protection in the calyx. (See spraying schedules, p. 75.) In 

 order to facilitate an even distribution of the spray over the smooth 

 waxy surface of the pears and to prevent objectionable blotching of 

 the mature fruit, a spreader should be used in the cover sprays. 



On account of the importance of codling moth sprays, adequate 

 spraying machinery is essential. Much of the failure to control the 

 worms is due to the use of spray outfits that are too small or are in 

 poor condition. In many cases stationary spraying systems are much 

 more efficient than portable outfits. Sufficient pressure should be 

 maintained to enable the operator to reach the tops of the trees 

 easily, and the tops should be sprayed with especial care, since it is 

 more difficult to cover thoroughly fruit in the tops than that which 

 is nearer the ground. 



A number of insecticides may be used for controlling the codling 

 moth. Chief of them is acid lead arsenate. The powdered form is 

 ordinarily used at the rate of 3 pounds to 100 gallons of water, but 

 in severely infested orchards this quantity may be increased to 4 

 pounds. Fish oil and certain colloidal materials, ordinarily known 

 as spreaders, may be used to advantage to cause a larger quantity of 

 lead arsenate to adhere to the fruit, or to prevent blotching. Fish 

 oil may be used in the proportion of 1 pint or 1 quart to 100 gallons 

 of spray. Other spreaders or stickers should be used as recommended 



