62 DDT— Killer of Killers 



the control of such undesirable insect citizens as the spruce 

 budworm, gypsy moth, hemlock looper, pine tip moth, spittle 

 bug, pine sawfly, and white pine weevil, our nimble nimrods 

 and girl-scout leaders joined their brother nature-lovers, the 

 fishermen, in expressing fears that the lilting sound of the 

 chickadee as well as the drumming of the partridge would be 

 stilled forever. This fear, like many others relating to DDT, 

 was entirely unfounded. Extensive tests in which forest 

 areas were treated by airplane with as much as 5 pounds of 

 DDT per acre revealed very few dead birds, although the 

 bird population did show a marked reduction a few days 

 after the treatment, presumably because the insects — food 

 for the birds — had been killed off, and our feathered friends 

 had to seek elsewhere for their daily bread. But insects soon 

 moved in to repopulate the treated areas, and with them re- 

 turned the birds. 



But 5 pounds per acre is much more than is needed. 

 When from % to 1 pound of DDT per acre is used — and 

 this is all that is needed to control the forest insect pests — 

 many insects, particularly of the harmless or beneficial types, 



; still remain alive, and the feathered and furry inhabitants of 



*^ the woods are seemingly unaffeaed. 



The Kriler of Kiriers at Work 



Insecticides are of three different types: respiratory poi- 

 sons, stomach poisons, and contact poisons. The naphtha- 

 lene used for moth balls is an example of the first type. Such 

 poisons are very volatile, that Is, they evaporate rapidly. This 

 is a disadvantage, for it shortens the effective life of the 

 produa after it has been applied. Furthermore, in high con- 

 centrations the respiratory poisons repel inseas and thus drive 



