COLORADO EXPERIMENT STATION. 
9 
* Professor Goff in his experiments in 1884 spray¬ 
ed six trees three times with Paris green and com¬ 
pared them with four trees not treated. All of the 
apples, 9,198 in number, that grew on these ten 
trees were examined and it was found that 69 per. 
cent, of the injury was prevented on the treated 
trees. That is, there were but 31 wormy apples on 
the treated trees where there would have been 100 
wormy apples in the absence of the treatment. 
Dr. Forbes, in 1885 conducted a similar but 
more extensive experiment from which he con¬ 
cluded as follows: 
“The experiments above described seem to me to prove that, at 
least, seventy per cent, of the loss commonly suffered by the fruit 
growers from the ravages of the Codling Moth or apple worm, may 
be prevented at a normal expense, or, practically, in the long run, at 
no expense at all, by thoroughly applying Paris green in a spray, 
with water, once or twice in the early spring, as soon as the fruit is 
fairly set, and not so late as the time when the growing apple turns 
downward on the stem.” 
While employed at the Iowa Experiment Sta¬ 
tion in 1889 I conducted experiments for the des¬ 
truction of Codling Moth larvae by using London 
purple and Paris green and reported upon them in 
Bulletin 7 of that station. In one of these experi¬ 
ments three Duchess apple trees were sprayed once, 
May 18th, with a mixture of London purple in 
water in the proportions of one pound to 128 gal¬ 
lons and two other trees of the same variety were 
* Fo7irth Annual Report of the State Experi¬ 
ment Station , page 218. 
Miscellaneous Essays on Economic Entomology 
p. 26. Also XV Annual Report of the State En¬ 
tomologist of Illinois , page 7. 
