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CARBON BISULPHIDE FOR CRAYFISH. 



By Howard Evarts Weed, Agricultural College, Miss. 



Crayfish sometimes do mucli injury to corn and other crops in land 

 that contains considerable moisture through lack of proper drainage. 

 I have seen fields where the crayfish holes were so numerous that they 

 would average in number nearly nine to the square foot, and upon such 

 land it would, of coursej be impossible to raise any cultivated crop. 

 Such fields are generally abandoned, and only broom sedge and a few 

 of the coarser grasses will grow on land of this description. Crayfish 

 are also numerous along the bottom and sides of open ditches. By 

 their work along the levees of the Mississippi River they cause weak 

 places in the embankment, through which the water gets a little start. 

 Once let the water get started in this way and the hole is gradually 

 washed larger and soon the embankment gives way and an overflow is 

 the result. 



Such being the damage caused 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 1893 I noticed that the bottom of a wide, open ditch near the Exper- 

 iment Station building was lined with crayfish holes. Having doubts 

 as to whether or not carbon bisulphide would kill the crayfish, I poured 

 about an ounce of the liquid into each hole, closing the hole by press- 

 ing the dirt together with the foot as soon as the bisulphide was put in. 

 A stick was placed by the side of tbe place where each hole had been, 

 so as to enable me to tell if the same holes were reoi)ened 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 bisulphide had been 

 effective. No new holes were made along the ditch for three weeks, 

 and then only two, which were probably made by some newcomers. 



I have on two occasions dug the crayfish out the day following a 

 bisulphide treatment and found that they had been killed. Their holes 

 may be anywhere from 1 to 15 or more feet deep. They dig deep 

 enough to get water, and in wet weather or on low places the holes are 

 not so deep as in dry weather or on high places. For two years past 

 it has been a common j)ractice with me to treat crayfish holes with car- 

 bon bisuli^hide, and in every case, with but one exception, the treatment 

 has been successful. 



The i)articulars of this exception areas follows: In September, 1893, 

 a place on rather high but poorly drained land was graded and put in 

 shape for a tennis court. The ground being somewhat sloping, about 

 3 feet of earth 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 

 crayfish holes were noticed, both upon the part where the dirt had been 

 added and where it had been taken awav. These holes were treated 



