Agrochemical research over the last two decades has resulted in the discovery of chemically novel insecticides that mimic the action of the two insect growth and developmental hormones, the steroidal 20-hydroxyecdysone (20E) and the sesquiterpenoid juvenile hormone (JH). Bisacylhydrazines are non-steroidal agonists of 20E and exhibit their insecticidal activity via interaction with the ecdysteroid receptor proteins. Interestingly, two of the bisacylhydrazine (tebufenozide and RH-2485) insecticides are very selectively toxic to lepidopteran pests. These insecticides are safe to beneficial insects and have a benign ecotoxicological profile. Aromatic non-terpenoidal insecticides (fenoxycarb and pyriproxyfen) mimic the action of JHs. However, like the JHs, their exact mode of action is not well understood. These insecticides are toxic to a broad spectrum of insects during their embryonic, last larval, or reproductive stages. The insecticidal, ecotoxicological properties and the mode of action of the two groups of insecticides are reviewed in this article.

New insecticides with ecdysteroidal and juvenile hormone activity.

Publisher Summary This chapter describes the premetamorphic actions and general consideration of cellular and molecular actions of juvenile hormone (JH). The chapter focuses on the biological role of JH and of the prevailing concepts of the modes of actions of hormones. It also concentrates on the premetamorphic actions of JH and the present understanding of the molecular basis of this action. Juvenile hormone (JH) has been known to be critical for the regulation of both metamorphosis and reproduction in insects. JH has been isolated and chemically identified as a sesquiterpenoid. The biological effects of various JHAs are remarkably similar to those of the natural JHs, allowance being made for differences in effective dose and stability. Extraction of JH from a natural source suggests the use of this hormone as a pesticide, as it can be absorbed through an insect's cuticle and prevent normal development, and would presumably be refractory to development of resistance.

Cellular and Molecular Actions of Juvenile Hormone I. General Considerations and Premetamorphic Actions

If done properly, say the authors,Aedes aegypti suppression is a practical method to control urban dengue, yellow fever, and chikungunya viruses.

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Defining challenges and proposing solutions for control of the virus vector Aedes aegypti.

Novel furans and thiophenes, pharmaceutical compositions containing these compounds and their use as endothelin receptor antagonists are described.

Endothelin receptor antagonists

The tropical plant family Piperaceae has provided many past and present civilizations with a source of diverse medicines and food grade spice. The secondary plant compounds that produce these desired qualities function also as chemical defenses for many species in the genus Piper. The compounds with the greatest insecticidal activity are the piperamides. Many studies have shown the effectiveness of Piper spp. extracts for the control of stored products pests and recently studies from our laboratory group have tested the extracts of Piper. nigrum, P. guineense and P. tuberculatum against insect pests of the home and garden. These results and those from investigations that examined the biochemical and molecular modes of action of the piperamides singly or in combination will be the focus of this review. The conclusions of our current work with Piperaceae are that Piper extracts offer a unique and useful source of biopesticide material for controlling small-scale insect out-breaks and reducing the likelihood of resistance development when applied as a synergist with other botanical insecticides such as pyrethrum.

A review of Piper spp. (Piperaceae) phytochemistry, insecticidal activity and mode of action

Insecticidal Unsaturated Isobutylamides: From Natural Products to Agrochemical Leads

2-[1-Methyl-2-(4-Phenoxyphenoxy) Ethoxy] Pyridine as a New Insect Juvenile Hormone Analogue : Induction of Supernumerary Larvae in Spodoptera litura (Lepidoptera : Noctuidae)

Laboratory evaluation of 2-[1-methyl-2-(4-phenoxyphenoxy) ethoxy] pyridine against larvae of mosquitoes and housefly

The induction of an imperfect supernumerary larval moult by juvenile hormone analogues in Manduca sexta

(3, 4-methylenedioxyphenyl)-(2E, 4E)-2, 4-undecadienamide] analogues and their structureinsecticidal activity relationships with respect to the amine and the carbon chain moieties. It has been discovered that the terminal benzyl group could be replaced by a phenoxy group without loss of activity and N-isobutyl-l2-(3, 4-methylenedioxyphenoxy)-3-methyl-(2E, 4E)2, 4-dodecadienamide was selected as the most potent insecticidal amide in this group against Callosobruchus chinensis (adzuki bean weevil). This amide also revealed noticeable toxicities against Chilo suppressalis (rice stem borer) as well as Musca domestica (housefly).

Isamu Nakayama

Papers

Insecticidal Unsaturated Isobutylamides: From Natural Products to Agrochemical Leads

2-[1-Methyl-2-(4-Phenoxyphenoxy) Ethoxy] Pyridine as a New Insect Juvenile Hormone Analogue : Induction of Supernumerary Larvae in Spodoptera litura (Lepidoptera : Noctuidae)

Laboratory evaluation of 2-[1-methyl-2-(4-phenoxyphenoxy) ethoxy] pyridine against larvae of mosquitoes and housefly

The induction of an imperfect supernumerary larval moult by juvenile hormone analogues in Manduca sexta

Chemistry and Insecticidal Activities of Piperaceae Amides and Their Synthetic Analogues