CONTROL OF CODLING MOTH IN COLORADO. 9 
By reference to Table 7 it will be noted that-in each instance the 
coarse sprays, as applied with the short rod and Bordeaux nozzle, 
gave control inferior to that on the plats treated with the poles and 
whirlpool-disk nozzles. Thus, plat I, fine spray, yielded 89.48 per 
cent of fruit free from worms in comparison with 79.54 per cent in 
plat II, which was-treated with the coarse spray. In plat III, 
sprayed with the disk nozzles, there was 85.05 per cent of uninfested _ 
fruit, whereas in plat IV, treated by means of the Bordeaux nozzle, 
there was but 71,06 per cent of fruit free from worms. Again, in 
plat V, which was treated with the fine spray, there was 89.70 per 
cent of worm-free fruit in comparison with 81.43 per cent in plat VI, 
which was sprayed with the Bordeaux nozzle. The untreated plat, 
plat VII, produced 30.98 per cent of fruit free from worms. 
It is the belief of the writers that the coarse sprays do not adhere 
so readily to the fruit, especially to the waxy skin of apples of the 
Ben Davis type, as do the fine mist sprays. It is believed further 
that the distribution of the poison is more thorough with the spray 
poles and disk nozzles than with the short rod and Bordeaux nozzle. 
The results of this experiment considered as a whole seem to show 
that three cover sprays were more efficient than five. But this an- 
omaly may perhaps be accounted for by the fact that there was no 
fruit in plats V and VI the preceding year, it having been destroyed 
by the spring freezes; hence, there being no overwintering larve on 
these trees, the infestation came solely from moths that migrated 
from other trees. | 
A further study of Table 7 will show, as in the experiments of 
1915 (Table 4), that the average number of worms per apple was 
lowest where the best control was obtained, with a range in this 
respect among the sprayed plats of from 0.14 to 0.40. In the 
unsprayed plat there was an average of 1.43 worms per apple. The 
spray material readily checked the worms from gaining entrance 
through the calyx, over 90 per cent of the larve having entered the 
fruit through the side. In the sprayed plats from 2 to 9.99 per cent 
of the wormy fruit was infested at the calyx while in the unsprayed 
plat 28.43 per cent of the wormy fruit was caused by larve that en- 
tered by way of the calyx. 
The average number of stings in the sprayed plats for all apples 
varied from 0.34 to 0.82 and in the unsprayed plat the average 
number was 0.23. 
47056°—21—Bull. 959 -——2 
