CONTROL OF CODLING MOTH IN COLORADO. 25 



As will be noted in Table 10, plat I yielded 70.99 per cent of 

 fruit free from worms, an improvement in favor of the traps over 

 plat II, which was untrapped but received the same number of 

 spray applications (six in all) and which yielded 62.1 per cent of 

 worm-free fruit. On the other hand, the traps did not improve the 

 results in plat V, which, like plat VIII, received a total of five appli- 

 cations, the yield of worm-free fruit in these two plats being 72.29 

 per cent and 73.49 per cent, respectively. 



From the foregoing experiments it will be seen that the traps 

 captured an average of from 197.05 to 311.53 individuals per tree; 

 but contrary to what might be expected, the reduction in the num- 

 ber of insects was not generally followed by a corresponding de- 

 crease in the percentage of wormy fruit. This would appear illogical, 

 and it will therefore be necessary to make further tests covering a 

 longer period of time before the value of the codling-moth traps as 

 a supplementary control measure can be determined. 



SPRAYING EXPERIMENTS IN 1918. 



The spraying experiments in 1918 were conducted in the Red 

 Cross orchard on a block of Gano trees about 13 years of age. These 

 trees were subdivided into 12 plats, of which 10 were sprayed and 

 the remaining 2 were untreated checks located in diagonally opposite 

 corners of the orchard. 



Table 18 shows the treatment given in the different plats. Arse-' 

 nate of lead, powder, at the rate of 1 pound to 50 gallons was used 

 in all of the sprayed plats, except in plats IX and X where the 

 strength was reduced to one-half pound to 50 gallons. Fish-oil soap 

 at the rate of 2 pounds to 50 gallons was used as a spreader and 

 sticker for the arsenate of lead in plats III, IV, VII, VIII, and IX. 

 The codling-moth trap was applied to all trees in plats I, III, V, 

 and VII. 



The sprays were applied by means of a power sprayer delivering 

 about 225 pounds' pressure to two leads of hose. Two spray poles 

 were employed in all treatments, one being operated from the tower 

 and the other from the ground. In the calyx application Bordeaux 

 nozzles were used, but these were replaced by whirlpool disk nozzles 

 for the cover sprays. 



As shown in Table 19, plats I to IV received, in addition to the 

 calyx treatment, five cover sprays, three for the first brood and two 

 for the later broods, and plats V to X were given one loss cover 

 spray, making a total of four, two of which were applied for the 

 first-brood larvie and two for protection against the second and 

 third broods. 



