Forest Preserve District of Cook County, Illinois
Nature Bulletins
Newton Home Page

Introduction and Instructions

Search Engine

Table of Contents



More About DDT
Nature Bulletin No. 37   October 20, 1945
Forest Preserve District of Cook County
Clayton F. Smith, President
Roberts Mann, Supt. of Conservation

Since issuing the previous bulletin on DDT, the Forest Preserve District has received numerous reports on this subject from several government agencies which are conducting experiments with DDT, and from individual scientists also studying its effects upon other insects, birds, mammals and plants.

It appears that mosquitoes and flies are more sensitive than most other insects but that no field tests have been carried out which did not also result in killing other kinds, due to excessive local dosages, This is serious.

Many of our fruits, vegetables and flowers are cross-pollinated by insects, and were such insects destroyed these crops would be greatly reduced with disastrous results. Further, insects and their allies, such as the countless mites which live in the litter of decaying leaves and other vegetable matter carpeting a forest floor, play a vital role in the production of a mature soil and the health of the forest.

All experiments on spraying forest areas with DDT which have included careful biological studies, confirm the opinion that such operations are potentially dangerous to most insects and their allies as well as to mammals, birds, reptiles, fish, amphibians and even some plants. Sometimes it kills birds and sometimes not. It has not been proven whether the birds die from eating the insects or from direct effects. The dosage, denseness of foliage, latitude, temperature, etc. seem to be the important factors.

In water its effects are deadly to fish, mussels, aquatic insects and even some plants unless the dosage is very light.

The consensus of opinion is that DDT should not be used other than in buildings, on dumps, etc., unless under the direction of competent scientists, and that it should not be used at all in the forest preserves until more is known about it.

To return to the Nature Bulletins Click Here!
Hosted by NEWTON

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (, or at Argonne's Educational Programs

Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Sponsered by Argonne National Labs