Blister Beetle (Coleoptera: Meloidae) Mortality Evaluated During Alfalfa Harvest

Abstract

A striped blister beetle, Epicauta occidentalis Werner, found aggregating in Kansas alfalfa fields, can be incorporated into baled hay and has been documented to cause horse deaths. Different types of alfalfa harvest equipment and operation were evaluated to quantify, blister beetle mortality using simulated swarms of known numbers. Mowing was responsible for most of the beetle mortality. A self-propelled mower-windrower with crimper rollers removed gave the lowest beetle mortality of any equipment tested. A self-propelled mower-crimper-windrower gave the second lowest mortality. Although the sicklebar mower is widely recommended to reduce cantharidin contamination, identification of previously unrecognized factors related to equipment operation has clarified its contribution to blister beetle mortality, Three sources of beetle mortality ranked from most to least important were wheel traffic over mowed forage before beetles could disperse, crimping. and, finally, the cutting step itself. Raking and baling steps dislodged beetles from forage.