This am posting By Chuck Demas, triggered my memory. If it's dry, Take a 1 gal milk jug place 1 qt of water in the bottom. Take a soft drink bottle, Cut off top an bottom, and cut up the side. Roll it up to make a "Tube" insert most of the way into the milk jug and place near nest. Another option with above, for a fly trap add about 1 cup of household ammonia and place near compost or manure piles. If it's wet toss about a pint of kerosene or diesel fuel on ground nest just about dark. toss on lite match. Have water or co2 handy. BE shure the ground is wet, and DO NOT USE GASOLINE Byron