EFFECTS OF DDT AND OTHER INSECTICIDES 



19 



even coverage and to prevent local 

 overdosage. 



Because of the sensitivity of 

 fishes and crabs to DDT, avoid, as 

 far as possible, direct applications 

 to streams, lakes, and coastal 

 bays. 



In aerial applications over 

 aquatic areas, use one-fifth pound 

 or less of DDT to an acre in oil 

 solution to avoid damage to fishes, 

 crabs, or crayfishes. If treatment 

 is repeated several times in a sea- 

 son, use one-tenth pound to an 

 acre or less. As a greater per- 

 centage of the applied dosage is 

 deposited at the water surface by 

 most ground methods of applica- 

 tion, these dosages should be re- 

 duced by 50 percent when ground 

 spray equipment is used. 



In forest areas use less than 2 



pounds of DDT to an acre to avoid 

 damage to birds, amphibians, and 

 mammals. Because of its great 

 toxicity to many aquatic forms, 

 use smaller quantities of DDT in 

 emulsions. 



Wherever DDT is used, make 

 careful before and after observa- 

 tions of mammals, birds, fishes, 

 and other wildlife. 



In the control of early appear- 

 ing insect pests, apply DDT, if 

 possible, just before the emer- 

 gence of leaves and the main 

 spring migration of birds ; for late 

 appearing pests, delay applica- 

 tions, whenever practicable, past 

 the nesting period of birds. Ad- 

 just crop applications and mos- 

 quito-control applications so far 

 as possible to avoid the nesting 

 period. 



U. S. GOVERNMENT PRINTING OFFICE 791813 



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