STRAW ITCH MITE, PYEMOTES-TRITICI, INFESTATION IN BROME SEED RELATED TO ACUTE DERMATITIS IN MICHIGAN GRANARY WORKERS

An infestation of Pyemotes tritici, the straw itch mite, apparently ca used dermatitis on the arms' and trunks of four workers in south-centr al Michigan who had unloaded a shipment of brome seed bags. Sampling o f bag surfaces and contents indicated that mites occurred inside and o n the surface of brome seed bags, but not in bags of other seed presen t at the site. One bag of fescue in contact with brome seed bags had m ites on its surface. Pyemotes tritici densities on the brome seed bags ranged from 0.7-5.6 per cm2 while infestations in brome seed ranged f rom 0.08-0.33 mites per ml of seed. An insect repellent containing DEE T was effective in preventing mite bites.