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Most of the 40 chemical companies now looking for safer, more specific insecticides simply screen thousands of chemicals each year for their possible insect-killing value. But university and government researchers, by and large, are investigating more elegant biological controls such as introducing parasites, sterile males, specific diseases or natural hormones...

Author: NO WRITER ATTRIBUTED | Title: Third-Generation Pesticides | 5/11/1970 | See Source »

These chemicals, called juvenile hormones, are made in two small glands in insects' heads. Juvenile hormone must be secreted at certain stages in an insect's life and not secreted at other times...

Author: NO WRITER ATTRIBUTED | Title: Third-Generation Pesticides | 5/11/1970 | See Source »

...hormonal insecticides were to succeed, they would have to attack only one pest, while leaving the species' natural insect predators unharmed. Otherwise, hormones would be merely a more potent variety of DDT from an ecologist's point of view...

Author: NO WRITER ATTRIBUTED | Title: Third-Generation Pesticides | 5/11/1970 | See Source »

Lynn M. Riddiford, assistant professor of Biology, and a Czech scientist discovered that juvenile hormone must be absent from insect eggs for normal hatching to take place. This finding led to the possibility of releasing males with juvenile hormone on their genitalia. Every wild female that mates with one of these males would become sterile. If enough sterilizing males are let loose, the target insect's population would drop, but the hormone would effect no other species...

Author: NO WRITER ATTRIBUTED | Title: Third-Generation Pesticides | 5/11/1970 | See Source »

Once anti-hoormone is developed, insects treated with the substance will skip their normal larval development and become miniature adults soon after hatching. Presumably the insects would be sterile, but "at any rate it makes the insect menace smaller," Williams said...

Author: NO WRITER ATTRIBUTED | Title: Third-Generation Pesticides | 5/11/1970 | See Source »

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