There are about 100 species of crayfish in North America. Most are strictly aquatic but a few live in non-permanent water or semi-aquatic situations. They burrow into the soil to get to water when free water is not available on the surface. Some crayfish burrow into the soil even when surface water is available.
Written by Lee Townsend, Extension Entomologist, University of Kentucky College of Agriculture
Burrowing crayfish ‘cast’ up muddy, knobby, hollow columns called ‘chimneys’* These ‘chimneys’ become dry and brittle and withstand being washed flat by watering or rain. Numerous chimneys in a lawn are unsightly and interfere with mowing. Heavy, low lying soil, especially near ponds and streams, is more likely to be damaged by crayfish, than high, well-drained, light soil.
Poisoning of large areas to control crayfish can contaminate nearby bodies of water. However, individual burrows can be treated to kill the crayfish so that chimneys will not be rebuilt after you knock them down. The following burrow treatments are suggested by the U.S. Fish and Wildlife Service, USDA.
1. Sodium hydroxide (lye) at the rate of two or three pellets (1/2 tsp) per burrow provides effective control. This method is used by H. S. Swingle, Fish Culturist, Auburn, Alabama and apparently it is effective in control of crayfish in narrow earth dams.
2. Mix two quarts of turpentine and 1/4 pound of soap powder with one quart of water. Mix one part of this stock solution in 50 parts of water. One to two ounces of this liquid should be applied into each crayfish burrow and the opening of the burrow closed by pressing the earth together with the foot.