OPERATING THE HATCHERY 



The amounts of commercial solu- 

 tions of 2,4-D that are required to 



spray an acre of water are shown 

 in the following dilution table: 



Under average conditions, 2.5 

 p. p. m. sodium arsenite will provide 

 adequate control of rooted vegeta- 

 tion as well as pond scum. In some 

 waters of high mineral content, par- 

 ticularly in the Southwest, 8 p. p. m. 

 or more may be required. This can 

 only be determined by trial. 



The amount of liquid sodium ar- 

 senite (containing 4 pounds of a,r- 

 senious oxide per gallon) that 

 should be used in a section of pond 

 where the average depth and surface 

 area in square feet are known and 

 where a concentration of 8 p. p. m. 

 is desired is as follows: 



48 



