# GTBOP Webinar Archives — Matching
Getting the Best of Pests — Processed webinar archives for the UGA Center for Urban Agriculture

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# GTBOP Moodle Matching Exercises

## Principles of Insecticide Mode of Action — Dr. Michael Scharf

Webinar Date: October 18, 2017 Series: Structural Pest Control Activity Type: Matching Exercises Exercises: 3 Total Pairs: 26 (8 + 10 + 8)

### CHAIN OF CUSTODY

- Source documents: Corrected SRT (GTBOP_Transcript_2017-10-18_InsecticideMOA.srt) + Archive Package (GTBOP_Archive_Summary_2017-10-18_InsecticideMOA.md)
- All terms, definitions, and relationships derived exclusively from presentation content

### Matching Exercise 1: Insecticide Classes and Their Target Sites

Timestamp Reference: 28:40 – 39:05 (primary coverage area) Type: Product-Target Site Matching

Instructions: Match each insecticide class in Column A with the target site it affects in Column B. Note: Column B contains two extra items.

# | Column A |  | Column B
--- | --- | --- | ---
1 | Pyrethroids |  | a) Chloride channels
2 | Fipronil (phenylpyrazole) |  | b) Acetylcholine receptor
3 | Nicotinoids |  | c) Muscular calcium channels
4 | Organophosphates and carbamates |  | d) Axonal sodium channels
5 | Diamides (chlorantraniliprole) |  | e) Acetylcholinesterase enzyme
6 | Indoxacarb (oxadiazine) |  | f) Mitochondria (energy production)
7 | Abamectin (avermectin) |  | g) Chitin synthesis enzymes
8 | Chitin synthesis inhibitors |  | h) Glutamate-gated chloride channels
|  |  | i) Juvenile hormone receptors
|  |  | j) Axonal sodium channels (blockage)

Answer Key: 1 → d, 2 → a, 3 → b, 4 → e, 5 → c, 6 → j, 7 → h, 8 → g

Notes: - Items 1 and 6 both target sodium channels but through opposite mechanisms (stimulation vs. blockage), which is why they map to separate entries (d and j). This distinction is a key teaching point from the presentation. - Distractors: (f) mitochondria and (i) juvenile hormone receptors are legitimate target sites discussed elsewhere in the presentation but do not match the classes listed in Column A.

Source in transcript: Blocks 301–343 (target site roadmap), 346–362 (sodium channels), 363–387 (chloride channels), 388–407 (acetylcholine), 429–444 (diamides), 466–482 (IGRs)

### Matching Exercise 2: Insecticide Mode of Action Effects

Timestamp Reference: 17:51 – 47:00 (spans full classification section) Type: Product-Effect Matching

Instructions: Match each insecticide or insecticide class in Column A with the physiological effect it produces in insects, as described by Dr. Scharf, in Column B. Note: Column B contains two extra items.

# | Column A |  | Column B
--- | --- | --- | ---
1 | Pyrethroids / pyrethrins |  | a) Blocks chloride channels, causing nervous system excitation
2 | Fipronil |  | b) Stimulates muscular calcium channels, causing contraction followed by energy depletion and paralysis
3 | Indoxacarb |  | c) Stimulates sodium channels, causing rapid knockdown and excitation
4 | Organophosphates |  | d) Inhibits chitin synthesis enzyme, causing death during molting
5 | Diamides |  | e) Blocks sodium channels, causing paralysis ("on switch stuck in off position")
6 | Juvenile hormone analogs (pyriproxyfen) |  | f) Inhibits acetylcholinesterase, causing excitation from neurotransmitter buildup
7 | Chitin synthesis inhibitors |  | g) Mimics juvenile hormone, causing cuticle deformation and extra juvenile stages
8 | Abamectin |  | h) Stimulates chloride channels, causing inhibition and paralysis
9 | Silica gel / diatomaceous earth |  | i) Abrades waxy cuticle layer, causing water loss and dehydration
10 | Nicotinoid-pyrethroid combinations |  | j) Stimulates acetylcholine receptors and sodium channels simultaneously (potentiation)
|  |  | k) Disrupts mitochondrial respiration, depleting cellular energy
|  |  | l) Blocks acetylcholine receptors, preventing nerve signal transmission

Answer Key: 1 → c, 2 → a, 3 → e, 4 → f, 5 → b, 6 → g, 7 → d, 8 → h, 9 → i, 10 → j

Notes: - This exercise tests understanding of both the target site AND the specific mode of action (stimulation vs. blockage vs. inhibition) — the core teaching framework of the presentation. - Distractors: (k) mitochondrial disruption is discussed for products like hydramethylnon but is not paired with any Column A item; (l) is a plausible-sounding but incorrect mechanism not described in the presentation.

Source in transcript: Blocks 184–205 (four modes of action), 346–362 (sodium channels), 363–387 (chloride channels), 388–407 (acetylcholine), 408–420 (combinations), 429–444 (diamides), 466–482 (IGRs), 499–511 (dusts)

### Matching Exercise 3: Practical Factors Affecting Insecticide Performance

Timestamp Reference: 48:15 – 56:30 (practical factors section) Type: Timing-Practice Matching

Instructions: Match each practical factor or scenario in Column A with the correct explanation or outcome described by Dr. Scharf in Column B. Note: Column B contains two extra items.

# | Column A |  | Column B
--- | --- | --- | ---
1 | Excess food in a cockroach account |  | a) Can pass insecticide through two digestive tracts and still affect a third individual
2 | Dirt and grease on treated surfaces |  | b) Physically bind and tie up insecticides, reducing their effectiveness
3 | Cockroach secondary/tertiary kill |  | c) Enables slow-acting insecticides to spread through food sharing and grooming
4 | Trophallaxis and allogrooming in social insects |  | d) Competes directly with bait placements, reducing consumption by target pests
5 | Flea larvae exposed through adult flea feces |  | e) Causes the insecticide's active ingredient to degrade faster in the environment
6 | UV light exposure on raw insecticides |  | f) Larvae consume insecticide-laden feces of treated adults as a nutritional source
7 | Formulations (inerts, stabilizers, attractants) |  | g) Enhance stability, extend longevity, improve safety, and keep active ingredients dissolved in water
8 | Product rotation every 3 months or monthly |  | h) Helps manage resistance by alternating between different modes of action
|  |  | i) Increases the LD50 of the product, making it less toxic to target pests
|  |  | j) Converts neurotoxic insecticides into non-repellent formulations

Answer Key: 1 → d, 2 → b, 3 → a, 4 → c, 5 → f, 6 → e, 7 → g, 8 → h

Notes: - This exercise bridges the gap between toxicology and practice — the section of the presentation Scharf described as "where toxicology interfaces with practice." - Distractors: (i) is plausible-sounding but reverses the relationship (formulations don't increase LD50 for targets); (j) is a fabricated mechanism not described in the presentation.

Source in transcript: Blocks 515–547 (stability and formulations), 548–567 (pest behavior), 568–585 (sanitation), 586–611 (resistance management)

## Moodle Activity Verification

- [x] All terms, definitions, and relationships derived from presentation content
- [x] Timestamp references verified against corrected SRT
- [x] No external knowledge required to answer correctly
- [x] Matching items unambiguous based on presentation content
- [x] 1–2 plausible distractors included per exercise to prevent elimination guessing
- [x] Answer keys unambiguously correct per speaker's content
- [x] Exercises cover early (target sites), middle (modes of action and effects), and late (practical factors) presentation content