Crawfish are not insects, but freshwater crustaceans resembling small lobsters. Crawfish (also known as crawdads, mudbugs, crayfish) are not harmful to turfgrass, but can become numerous in poorly drained soil. They build unsightly tubes that may reach several inches in height. There are no registered or recommended pesticides for crawfish control. Improving drainage may reduce earthworm populations and crawfish activity.
For more information on crawfish, we recommend the book Texas Crawdads. (Texas A&M AgriLife Extension Service derives no financial benefit from the sale of this book.)