BLISTER BEETLE (COLEOPTERA, MELOIDAE) MORTALITY EVALUATED DURING ALFALFA HARVEST

A striped blister beetle, Epicauta occidentalis Werner, found aggregat ing in Kansas alfalfa fields, can be incorporated into baled hay and h as been documented to cause horse deaths. Different types of alfalfa h arvest equipment and operation were evaluated to quantify blister beet le mortality using simulated swarms of known numbers. Mowing was respo nsible for most of the beetle mortality. A self-propelled mower-windro wer with crimper rollers removed gave the lowest beetle mortality of a ny equipment tested. A self-propelled mower-crimper-windrower gave the second lowest mortality. Although the sicklebar mower is widely recom mended to reduce cantharidin contamination, identification of previous ly unrecognized factors related to equipment operation has clarified i ts contribution to blister beetle mortality. Three sources of beetle m ortality ranked from most to least important were wheel traffic over m owed forage before beetles could disperse, crimping, and, finally, the cutting step itself. Raking and baling steps dislodged beetles from f orage.