# GTBOP Webinar Archive — Extension Agent Resource
## Principles of Insecticide Mode of Action

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### 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 |

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### 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.

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### Viewing Instructions for Asynchronous Use

1. Total viewing time is approximately 1 hour and 7 minutes, including the Q&A session.
2. Attendees must view the entire presentation to receive credit.
3. The presentation includes a 57-minute lecture followed by a 10-minute moderated Q&A.
4. A sign-in sheet must be completed and returned per standard GTBOP procedures.

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### 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.

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### 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.

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### 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 |

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### 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

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*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.*