16 BULLETIIsr 959, U. S. DEPARTMENT OF AGRICULTURE. 



and witli a mixture containing 10 per cent of lead arsenate there was 

 only 14.38 per cent of uninfested fruit, all of which would indicate 

 practically no control. Furthermore, the dust was not nearly so 

 effective as the liquid sprays in preventing the entrance of worms at 

 the calyx. 



The two plats sprayed by the grower, plats XIV and .XV, produced 

 a lower percentage of control than those treated by the experimental 

 staff. Plat XIV, in which spray poles and Bordeaux nozzles were 

 used throughout the season, yielded 40.21 per cent of uninfested 

 fruit, whereas plat XV, in which the spray gun was employed for the 

 cover sprays, gave but 30.22 per cent of worm-free fruit. 



The abundance of the codling moth in this orchard is indicated in 

 plats XVI and XVII, both of which were untreated and which pro- 

 duced but 8.83 and 8.54 per cent of worm-free fruit. The number of 

 stings in these plats, as was to be expected, was not large, there being 

 88.16 per cent of fruit free from stings in plat XVI and 87.42 per cent 

 in plat XVII. It will be further noted that in these plats the per- 

 centage of calyx worms was large, 30. 2Q and 28.92 per cent, respec- 

 tively, with 47.09 and 47.50 per cent of the wormy apples infested at 

 the calyx end. 



Codling-Moth Trap Experiments in 1917. 



A section of the J. B. Hunter orchard near Fruita, Colo., consisting 

 of Ben Davis and Gano apple trees, was divided^into three plats. 

 Plat I, containing 60 trees, was banded and sprayed; plat II, having 

 108 trees, was provided with the codling-moth trap and sprayed; 

 while plat III, 99 trees, received no other treatment than five spray 

 applications as described below. 



The spray applications, five in all, were made by the grower on all 

 the plats as follows: Calyx spray applied June 1-2; first cover spray 

 June 14-16; second cover spray July 11; third cover spray July 27; 

 fourth cover spray August 16. A power sprayer was used throughout 

 the season and this was equipped with Bordeaux nozzles for the 

 calyx application and whirlpool-disk type nozzles having a large 

 aperture disk for all of the cover treatments. 



The data obtained from the examination of the dropped and har- 

 vested fruit from eight trees in each plat will be found in Table 11. 

 It will be noted therein that plat III, which had only the spray 

 treatment, produced 76.56 per cent of fruit free from worms, a higher 

 percentage than that of plats I and II, which -received theoretically 

 better treatments. There is no logical explanation for these results 

 other than the possibility of unevenness of infestation and yield of 

 fruit. 



