Zoecon

Environmental Health Perspectives

Vol. 14, pp. 119-126, 1976

Insect Growth Regulators and Insect

Control: A Critical Appraisal

by J. B. Siddall*

Insect growth regulators (IGRs) of the juvenile hormone type alter physiological processes essential to insect development and appear to act specifically on insects. Three

natural juvenile hormones have been found in insects but not in other organisms. Future

use of antagonists or inhibitors of hormone synthesis may be technically possible as an advantageous extension of pest control by IGRs.

A documented survey of the properties, metabolism, toxicology, and uses of the most

commercially advanced chemical, methoprene, shows it to be environmentally acceptable

and toxicologically innocuous. Derivation of its current use patterns is discussed and

limitations on these are noted. Residue levels and their measurement in the ppb region

have allowed exemption from the requirement of tolerances in the EPA registered use of

methoprene for mosquito control. Tolerances for foods accompany its fully approved use

for control of manure breeding flies through a cattle feed supplement. The human health

effects of using this chemical appear to be purely beneficial, but further advances through

new IGR chemicals appear unlikely without major changes in regulatory and legislative

policy.

Objective

Since the purpose of this conference is to review

current knowledge and to anticipate future human

health effects of new approaches to insect pest control, it is particularly appropriate to review and discuss insect growth regulators. At this time they

represent the newest of all approaches to operational and commercial insect control. Only one insect growth regulator (IGR) has so far achieved the

status of full commercial registration by any

government regulatory agency (in this case the En-

vironmental Protection Agency) for its uses, and

my discussion will therefore focus on this chemical

(1,2), common name...