June, ’23 
haseman: arsenic, calyx cups and codling moth 
273 
glance at the records on calyx worms taken at picking time shows best 
results with 150 pounds pressure. The variety used throughout this 
test was Jonathan. 
Determining the Lethal Dosage of Arsenic for Apple Worms 
It is a recognized fact that with careful systematic spraying one can 
produce a crop with a very small percent of wormy fruits when checks 
show a very high percent of worms. The calyx spray properly applied 
may keep a crop of apples almost free from calyx-end-worms. This 
may properly be interpreted as meaning that the arsenic placed in the 
calyx cups is sufficient to poison worms attempting to enter the fruit 
at that point. To determine experimentally whether or not this is 
true, careful laboratory feeding experiments were made during the past 
fall. The dosage fed to the worms under experiments was carefully 
determined by first preparing in distilled water, solutions containing 
varying quantities of arsenate of lead. The solution used contained 
one gram dry arsenate of lead to 100, 400, 1600, 6250, 10,000, 15,000 
and 1,000,000 cc. of water. Then after the solution to be used was 
thoroughly shaken to distribute the arsenate of lead evenly, one, or in 
some cases, two drops of the solution were dropped into a small cavity 
cut in a bit of apple. After slightly drying the treated bit of apple was 
then turned upside down over the worm in a small glass jar. In the 
majority of cases the worms at once set to work eating out the treated 
apple pulp, often leaving only a thin surface layer that usually dried so 
as to be unpalatable. In this way those worms which fed properly 
consumed the bulk of the treated pulp. By watching the worms, 
however, it was noted that some of the larger ones, that were not kept 
without food for a day or so just before making the tests, would cut off 
and discard bits of the surface treated pulp thus failing to consume the 
full dosage. The smaller hungry worms, however usually fed properly. 
This tendency on the part of some worms to discard bits of the treated 
pulp made it difficult to determine, just what part if not all, of the dosage 
was consumed in such cases. Repeated tests with careful examination 
to see just what was consumed are necessary in order to draw conclusions 
from feeding tests on the apple worms. 
In these feeding tests no worms under the second or third instar were 
used. All specimens used were taken from infested apples. Careful 
breeding experiments carried out at Ithaca, New York in 1909 showed 
that usually the larvae are in the third instar before they eat down into 
the pulp. These experiments therefore deal with worms varying in age 
