Nature Bulletin No. 31  September 8, 1945 - [edited April,1998]
Forest Preserve District of Cook County
Clayton F. Smith, President
Roberts Mann, Superintendent of Conservation

****:DDT

Large scale experiments are being conducted on selected areas scattered 
all over the United States and Canada. The U, S. Fish and Wildlife 
Service, the U. S. Forest Service, the Bureau of Entomology and Plant 
Quarantine of the Department of Agriculture, and the U. S. Public 
Health Service are among the agencies cooperating in these 
experiments. DDT is being applied in the form of dust, suspensions, 
solutions and emulsions, by means of airplanes, high-powered sprayers, 
knapsack sprayers, and hand atomizers.

It is being tested against leaf-eaters, bark beetles, wood borers, termites, 
and a number of sucking insects, including mosquitoes and flies. The 
experiments indicate that DDT far surpasses any previous used 
substance for control of insects harmful to forests, orchards, gardens 
and man himself. Its remarkable lasting qualities, even after rains, the 
small amount required per acre, and its suitability to application by 
plane, would seem to make it the answer to most problems of control of 
harmful insects.

BUT, these problems are complex. For instance: what do many birds 
feed on? Insects and their larvae. What keeps many harmful insects 
under control? Other insects. We now know that certain concentrations 
of DDT upon the surface of a pond or lake will kill the mosquito larvae, 
but they also kill every fish in that body of water, and the aquatic 
insects upon which fish feed. While it may kill the harmful moths in an 
orchard, it also kills the bees necessary for the polarizing and fruiting of 
that orchard. Its toxic effect in various concentrations, on beneficial 
insects, fish and wildlife is a serious problem which requires thorough 
investigation. DDT might do more harm than good. Carefully 
controlled experiments, watched by scientists specializing in the several 
fields involved, must be made.

Certain large areas of the Forest Preserve District are included within 
the boundaries of the DesPlaines Valley Mosquito Abatement District 
and the North Shore Mosquito Abatement District. We have requested 
the officials of these districts not to use DDT in the forest preserves 
until more definite knowledge is obtained from the experiments being 
carried on by the several government agencies. These agencies have 
been requested to supply us with up-to-the-minute bulletins of the 
results so obtained.