A sand-dune mesquite area with very  little interdunal vegetation was treated aerially one to three times with 2,4,5-T at 0.56kg/ha in an oil: water  emulsion. Four and five years after the initial treatment, the amount of blowing soil was evaluated using sandtraps located various distances from the  boundary between sprayed and unsprayed mesquite. The amount of wind-blown particles was greatly reduced on the area chemically treated to control mesquite. During the  windy season  the  amount  of  blowing soil  in  the unsprayed  area was more than 15-fold greater than at  180 m  into the sprayed area. Intermediate amounts were measured between boundary and 180 m  into the treated area.