2. 1. Neurosecretory cells in brain produce brain hormone,
stored in corpora cardiaca.
• BH send signal to prothoracic gland, produce
ecdysone hormone to stimulate the molting.
2. JH secreted by corpora allata.
Larva to larva
Mr. Karns Lectures for Biology, Seventh Edition Neil Campbell
and Jane Reece Chapter 45 Hormones and the Endocrine
3. • 20-hydroxyecdysone is ecdysteroid hormone which controls the
ecdysis, insects reproduction, including ovarian development and
• Synthesized from cholesterol or phytosteroids, obtain from its diet.
• The concentration of ecdysone in haemolymph increases at the time of
molting and then falls rapidly.
• 20-hydroxyecdysone bind to the ecdysteroid receptor.
• Methoxyfenozide selectively targets against lepidopterans pest.
• Halofenozide and tebufenozide effective against dipterans larvae.
• Stomach and contact poison.
• Low impact on most beneficial insects.
5. • Plays an important role in insects controlling development, metamorphosis,
reproduction and behavior.
• These agonist mimic the action of insect molting hormone 20E.
• Application of ecdysone agonists is effective only when concentration of
ecdysone in insects are low.
Mode of Action
7. Accelerating the molting
process by binding to the
Eclosion hormone and
Bursicon hormone not
Lack of sclerotization of the new cuticle
Liquefy the body
Prevents the larvae from completely
shedding its old cuticle
Precocious and incomplete molting
Resulting larva dies of starvation and desiccation
Actions in two ways
8. • Ecdysone agonists may disturb the embryonic development
• Inducing mortality and morphogenetic abnormalities
Larva with two heads
Slipped head capsule
Hamaidia H. and Soltani N., 2016. Ovicidal activity of an insect growth disruptor
(methoxyfenozide) against Culex pipiens L. and delayed effect on development.
Journal of Entomology and Zoology