23 
Such being the damage done by these pests, the question of 
how to destroy them becomes of no small importance, ■ and 
perhaps some experiments of mine in this direction may be of 
interest. In the spring of 1903 I noticed that the bottom of a 
wide, open ditch near the Experiment Station building was lined 
with craw'fish holes. Having doubts as to whether or no carbon 
bisulfide would kill the crawfish. I poured an ounce of bisulfide 
in each hole, closing the hole immediately with the foot by press- 
ing the surrounding dirt together. A stick was placed by the 
side of where each hole had been, so as to be able to tell if 
the same holes were reopened or if new ones were made. The 
ditch was examined every day for some time, but none of the 
holes were reopened, showing that the bisulfide had been effec- 
tive. No new holes were made along the ditch for three weeks, 
and then only two, which were probably made by some newcom- 
ers. 
Upon two occasions the •crawfish have been dug out the" day 
after the bisulfide treatment, when it wa^ found that they had 
been killed. Their holes may be anywhere from one to fifteen 
feet or more deep. They dig deep enough to get to water, and 
in wet weather, or on low places, their holes are not so deep 
as in dry weather or on higher places. For two years past it has 
been a common practice with me to treat crawfish holes with 
bisulfide, and in every case, .with but one exception, the treat- 
ment has been successful. 
The particulars of this exception are as follows: In Septem- 
ber, 1S93, a place on rather high, but poorly drained iand on 
the college campus, was graded and put in shape for a tennis 
court. The ground being somewhat sloping, about three feet 
was taken from one end and added to the other end. in order to 
make it level. A few days after the court was fixed, many craw- 
fish holes were noticed, both upon the end where the dirt had 
been added and where it had been taken away. These holes 
were treated in the usual manner with carbon bisulfide, fully 
expecting this treatment would rid the tennis court of the craw- 
fish. The next day, however, it was found that the holes had 
been reopened during the night, and a second treatment was 
made, using fully double the amount of the carbon bisulfide. 
The result of the carbon bisulfide being the same as the first, 
daily treatments were then made for over two weeks, in some 
cases nearly a pound of bisulfide being used. It was fully three 
months before the tennis court was free from the crawfish, but 
whether they left the ground for a more favorable situation, or 
were killed, I am not prepared to say. Bisulfide from the same 
can was effective in other places, so that the cause of failure 
was not due to the quality of the bisulfide used. 
Were it not for this one case of the failure of the carbon of 
bisulfide to do effective work, I would be prepared to recommend 
it for crawfish in all cases. The failure mentioned, however, 
was under somewhat unnatural conditions, and as we have used 
it at the station successfully over fifty times, with but this one 
case of failure, it may be said that the carbon bisulfide is nearly, 
if not quite, a complete remedy for crawfish. On land where 
they are so numerous it will not always pay to treat them in the 
manner described, as the treatment would cost nearly as much 
as the land. But in the garden and along the levees of the Mis- 
sissippi river, there is no question but that the treatment would 
pay. 
