8 Department Circular 367, U. S. Dept. of Agriculture 





Fig. 5. — Dusting the marginal zone of Field Lake. With the wind Mowing toward 

 the lake, the plane was flown outside of the tree line and the dust drifted into the 

 breeding area 



Fig. 6. — View of another dust cloud left in treating the marginal zone of Field Lake. 

 In this case the plane was flown on the lake side of the trees, since the drift was 

 toward the open field. The photograph also shows the heavy growth of w T ater 

 chinquapin, in a portion of the lake completely obscuring the water surface 



