Principles of Insecticide Mode of Action
Webinar Information
| Field | Details |
|---|---|
| Speaker | Dr. Michael Scharf, Purdue University |
| Moderator | Dr. Dan Suiter, UGA Extension Entomologist |
| Original Air Date | October 18, 2017 |
| Duration | 1 hour, 7 minutes |
| Series | Getting the Best of Pests — Structural Pest Control |
CEU Credit Information
Georgia Applicator Category:
- Cat 35 — Industrial, Institutional, Structural and Health Related: 2 HPC
Credit Eligibility: This archived presentation is suitable for asynchronous CEU delivery to licensed pest control operators holding Category 35 certification. Verify current CEU acceptance with the Georgia Department of Agriculture before scheduling.
Sign-in sheet and CEU documentation: Contact the UGA Center for Urban Agriculture or visit gabugs.uga.edu for current forms and procedures.
Viewing Instructions for Asynchronous Use
- Total viewing time is approximately 1 hour and 7 minutes, including the Q&A session.
- Attendees must view the entire presentation to receive credit.
- The presentation includes a 57-minute lecture followed by a 10-minute moderated Q&A.
- A sign-in sheet must be completed and returned per standard GTBOP procedures.
Content Summary
Dr. Michael Scharf of Purdue University covers insecticide classification and mode of action at a level appropriate for licensed pest control professionals. The presentation provides foundational knowledge that supports informed product selection, resistance management, and customer communication.
Topics covered include: a review of insect physiology as it relates to insecticide activity (nervous system, cuticle, digestive tract, tracheal system, musculature); the four basic modes of action (stimulation, blockage, modulation, inhibition); the LD50 concept and mammalian safety; five neurotoxic insecticide classifications (sodium channel agents, chloride channel agents, acetylcholine receptor agents, acetylcholinesterase inhibitors, combination products); four non-neurotoxic classifications (diamides, insect growth regulators, energy production inhibitors, cuticle dehydrating dusts); and practical factors affecting insecticide performance including formulations, pest behavior, sanitation, and resistance management through product rotation.
The Q&A session addresses: combination product resistance, new active ingredient development, IRAC classifications, nicotinoid vs. neonicotinoid terminology, oral vs. dermal toxicity routes, repellent vs. non-repellent insecticides, and essential oil-based products.
Key Takeaways for Extension Programming
- All insecticides work through one of four basic mechanisms — a useful teaching framework for applicators at any experience level.
- Nine insecticide classifications (five neurotoxic, four non-neurotoxic) cover the full landscape of available tools.
- Diamides represent a notably safe chemistry class for mammals — EPA initially required no signal word.
- Resistance is identified as the probable #1 cause of callbacks in cockroach accounts; rotation every 3 months or monthly is recommended.
- The IRAC classification system is highlighted as a free, practical resource for planning product rotations by mode of action group.
- Sanitation and IPM practices are framed as direct enhancers of chemical efficacy, not just standalone strategies.
Video Chapter Guide
For agents directing attendees to specific sections:
| Time | Topic |
|---|---|
| 0:00 | Introduction and Speaker Credentials |
| 1:45 | Why Understanding Mode of Action Matters |
| 8:26 | Insect Physiology Overview |
| 14:02 | Insecticide Classification Basics |
| 17:51 | Four Basic Modes of Action |
| 19:41 | LD50 Concept and Mammalian Safety |
| 22:46 | Neurotoxic Insecticide Classifications Begin |
| 32:24 | Sodium Channel Insecticides |
| 34:12 | Chloride Channel Insecticides |
| 36:20 | Acetylcholine Receptor Insecticides |
| 38:04 | Combination Products |
| 39:07 | Non-Neurotoxic Insecticides Begin |
| 40:02 | Diamides |
| 41:42 | Insect Growth Regulators |
| 45:18 | Energy Production Inhibitors |
| 46:56 | Cuticle Dehydrating Dusts |
| 48:15 | Factors Affecting Insecticide Efficacy |
| 54:19 | Resistance Management |
| 57:53 | Q&A Session Begins |
Additional Resources Referenced in Presentation
- Scharf & Suiter, “Insecticide Primer and Insecticide Mode of Action,” PCT Magazine, 2011
- Scharf & Suiter, Insecticide Basics for the Pest Management Professional, UGA publication (free)
- IRAC Mode of Action Classification Chart — irac-online.org
Getting the Best of Pests Webinar Series | University of Georgia Center for Urban Agriculture
For questions about this archive or CEU procedures, contact the Center for Urban Agriculture.