Insect Control: Biological and Synthetic Agents - Index of

4 Insect Growth- and
Development-Disrupting Insecticides
T S Dhadialla, Dow AgroSciences LLC,
Indianapolis, IN, USA
A Retnakaran, Canadian Forest Service,
Sault Ste. Marie, ON, Canada
G Smagghe, Ghent University, Ghent, Belgium
ß 2010 Elsevier B.V. All Rights Reserved
4.1. Introduction 121
4.1.1. Physiological Role and Mode of Action of the Insect Molting Hormone 122
4.2. Ecdysteroid Agonist Insecticides 124
4.2.1. Discovery of Ecdysone Agonist Insecticides and Commercial Products 124
4.2.2. Bisacylhydrazines as Tools of Discovery 127
4.2.3. Mode of Action of Bisacylhydrazines 130
4.2.4. Basis for Selective Toxicity of Bisacylhydrazine Insecticides 136
4.2.5. Spectrum of Activity of Commercial Products 138
4.2.6. Ecotoxicology and Mammalian Reduced Risk Profiles 140
4.2.7. Resistance, Mechanism, and Resistance Potential 140
4.2.8. Other Chemistries and Potential for New Ecdysone Agonist Insecticides 141
4.2.9. Noninsecticide Applications of Nonsteroidal Ecdysone Agonists; Gene
Switches in Animal and Plant Systems 142
4.2.10. Conclusions and Future Prospects of Ecdysone Agonists 145
4.3. Juvenile Hormone Analogs 145
4.3.1. Juvenile Hormone Action 145
4.3.2. Putative Molecular Mode of Action of JH 147
4.3.3. Pest Management with JHAs 149
4.3.4. Use of JHAs for Pest Management 151
4.3.5. Effects on Nontarget Invertebrates and Vertebrates 151
4.3.6. Conclusions and Future Research of JHAs 157
4.4. Insecticides with Chitin Synthesis Inhibitory Activity 157
4.4.1. Brief Review of Old Chitin Synthesis Inhibitors 157
4.4.2. New Chemistries and Products 161
4.4.3. Mode of Action and SAR 161
4.4.4. Spectrum of Activity 162
4.4.5. Ecotoxicology and Mammalian Safety 162
4.4.6. Resistance, Mechanism for Resistance and Resistance Potential 164
4.5. Conclusions and Future Prospects of Insect Growth- and Development-
Disrupting Insecticides 166
4.1. Introduction
In 1967 Carrol Williams proposed that the term
‘‘third generation pesticide’’ be applied to the potential
use of the insect juvenile hormone (JH) as an
insecticide, and suggested that it would not only be
environmentally benign but that the pest insects
would also be unable to develop resistance. However,
it took several years before the first commercial
juvenile hormone analog (JHA) made its debut
(reviews: Retnakaran et al., 1985; Staal, 1975).
Since then, several compounds that adversely interfere
with the growth and development of insects
have been synthesized, and have been collectively
referred to as ‘‘insect growth regulators (IGRs)’’
(review: Staal, 1982). Concerns over eco-toxicology
and mammalian safety have resulted in a paradigm
shift from the development of neurotoxic, broadspectrum
insecticides towards softer, more environmentally
friendly pest control agents such as
IGRs. This search has led to the discovery of chemicals
that: (1) interfere with physiological and biochemical
systems that are unique to either insects in
particular or arthropods in general; (2) have insectspecific
toxicity based on either molecular target site
or vulnerability to a developmental stage; and (3) are
safe to the environment and nontarget species. At