COLORADO EXPERIMENT STATION. I I 
crop of apples as cutting the weeds from their 
garden for the production of a crop of vegetables. 
As to the form of the poison to use, and the method 
and time.of application that will produce the best 
results, there is still much to be learned. 
THE POISON TO USE. 
9 
Some of the earliest experiments * with poisons 
for the destruction of the apple worm were made 
with white arsenic in solution and seemingly with 
good results. This substance, however, is objec¬ 
tionable because of its color which makes it liable 
to be mistaken for culinary articles, because, unless 
dissolved, it mixes with much difficulty in water and 
when mixed settles quickly to the bottom of the 
vessel and, because, when in solution it is very in¬ 
jurious to foliage, as proven by a large number 
of experiments by myself which were reported in 
Bulletin 2 page 30 and Bulletin 10 page 413 of the 
Iowa Experiment Station, 
London purple and Paris green are the two 
substances most commonly recommended and used 
for insecticidal purposes and, of these two, the form¬ 
er seems to be growing in favor on accounnt of its 
being cheaper, less liable to adulteration and light¬ 
er, so that it remains longer in suspension in water. 
On the other hand, experiments ** go to prove that 
Paris green is less injurious to foliage than London 
*See paper by Plan. J. N. Dixon in Rep. op Iowa 
State Horticultural Soc. por 1882. 
* * Bui. 5j, page 6, of the Mich. Exp. St a. Also 
Bill. 10 page 404 of the la. Exp. St a. 
