Understanding Insecticidesor

101 Ways to Kill a Cockroach

Philip G. Koehler

Margie & Dempsey Sapp Endowed Professor of Urban Entomology

Department of Entomology

University of Florida

Insecticide

• Any substance or mixture of substances intended for preventing, destroying, repelling, or mitigating insects.

Modes of Action of Insecticides

Nervous System Energy Production

Cellular Toxins

Cuticular Disrupters

Growth and Metamorphosis

Nervous System• Lethal spasms and seizures

• Insects flip on back

• Legs wiggle uncontrollably

Myths:Insecticide Causes Mad Cow Disease

by Fintan Dunne, Research by Kathy McMahonReprinted from eionews.com, email - news@eionews.com

Prions in human brains are damaged by lice lotions containing organophosphate. This can result in neurological diseases like CJD and Alzheimers later in life.

Insecticides that Affect the

Nervous System Nervous System

permethrindeltamethrin

PyrethroidsDDT

Sodium Channel

Nerves and Pyrethroids

Sodium Channels

Direction of Nerve Impulse Repeated nerve firing

Why do neurons like e-mail?

They like to send and receive lots of messages

Pyrethroids

• Allethrin• Bifenthrin• Cyfluthrin• Permethrin• Cypermethrin• Deltamethrin• d-phenothrin• Tetramethrin

Synthetically produced chemicals based on biologically active compounds in pyrethrum plant

Irritating to skinAllergiesActive at low concentrationsLipophilic

Talstar PL Granular: bifenthrin

• Unique sand core granular • Provides a 2 to 4 month

residual, supplying effective, long-term protection.

• Penetrates mulch and grass, with no watering needed.

• No odor • Low application rates

Pyrethroids Effects

• Action on Human System - Irritant

• Systemic Effects - Minimal

• Irritation Effects - Stinging, burning, itching, tingling, numbness of skin.

Cholinesterase

Insecticides that Affect the

Nervous System Nervous System

propoxurcarbaryl

permethrindeltamethrin

PyrethroidsDDT

Sodium Channel

CarbamatesPhosphates

chlorpyrifosmalathiondiazinon

Neuro-transmitters

Neuro-receptors

What happens when a neurotransmitter falls

in love with a receptor?

You get a binding relationship

Neurotransmitter and Receptor Types

• Small Molecule Neurotransmitter Substances– Acetylcholine (ACh)

– Dopamine (DA)

– Norepinephrine (NE)

– Serotonin (5-HT)

– Histamine

• Amino Acids– Gamma-aminobutyric acid (GABA)

– Glycine

– Glutamate

– Aspartate

Targeted by Insecticides

Cholinesterase Inhibitors

• Organophosphates

• Carbamates

ACh

Receptors

Causes repeated nerve firing

Organophosphates and Carbamates

• Organophosphates– Chlorpyrifos– Diazinon– Trichlorfon– Parathion

• Carbamates– carbaryl (Sevin)– propoxur (Baygon)

Chemicals which are derived from phosphoric and carbamic acid and bond with cholinesterase

Acute toxicityNot persistentHyper-excitationInsect flips on back with legs twitchingSulfur in formulation often causes strong odor

Dursban: Chlorpyrifos

• Proven Residual Control– Effective control makes it the perfect product for

maintenance accounts.

– Ability to provide control for several weeks, keeps customers protected between treatments.

• Broad Label for Varied Applications– Broad labeling allows use for almost any application

indoors or out.

– Designed to be used in homes and apartments, hospitals, stores, manufacturing plants and warehouses.

Organophosphate Effects• Action on Human System - Inhibits acetylcholinesterase

enzyme in tissues.

• Systemic Effects - Headache, dizziness, weakness, shaking, nausea, stomach cramps, diarrhea, sweating.

• Irritation Effects - Minimal rashes, but readily absorbed through the skin.

• Delayed/Allergic Effects - Loss of appetite, weakness, weight loss, and general feeling of sickness. Occasionally permanent harm to brain and nervous system.

N-Methyl Carbamates Effects

• Action on Human System - Reversible changes in acetylcholinesterase enzyme in tissues.

• Systemic Effects - Headache, dizziness, weakness, shaking, nausea, stomach cramps, diarrhea, sweating.

• Irritation Effects - Minimal rashes, but readily absorbed through the skin.

• Delayed/Allergic Effects - Loss of appetite, weakness, weight loss, and general feeling of sickness.

When does a brain get scared?

When it loses its nerve

Insecticides that Affect the

Nervous System Nervous System

propoxurcarbaryl

permethrindeltamethrin

PyrethroidsDDT

Sodium Channel

CarbamatesPhosphates

Imidacloprid

Acetylcholine receptor

Cholinesterase

chlorpyrifosmalathiondiazinon

Acetylcholine

Acetylcholine Receptor• Nicotine

• Chloronicotinyls

• Fluoronicotinyls

ACh-receptors

ACh

MuscarinicReceptors

Nicotinic Receptors

Chloronicotinyls

• Imidacloprid– Advantage -- pet treatment– Merit -- turf ornamentals– Premise -- termites

Affects insects first by paralyzing mouthpartsWater solubleSystemic in plantsSlow action

Premise: Imidacloprid

• No odor • Not repellent to termites• Low risk to your family, your pets, your home• Premise causes a range of effects:

– Pests stop feeding

– Premise Plus Nature™. This phenomenon makes termites susceptible to infection by naturally occurring organisms.

• Lateral Soil Movement causes spread to ensure thorough soil coverage

Insecticides that Affect the

Nervous System Nervous System

propoxurcarbaryl

permethrindeltamethrin

PyrethroidsDDT

Sodium Channel

chlordaneheptachlor

Cyclodienes

fipronil

Phenyl pyrazoles

GABA Receptor

CarbamatesPhosphates

Imidacloprid

Acetylcholine Receptor

Cholinesterase

chlorpyrifosmalathiondiazinon

GABA

GABA receptor

GABA Receptor in Central Nervous System

• Phenyl pyrazoles

• or

• Fiproles

GABA-receptors

GABAChloride ions

Fipronil

If some of Fred Flintstone's neurotransmitters

could talk, what would they say?

GABA-daba-doo

Phenyl pyrazoles• Fipronil

– Chipco Choice -- mole crickets & grubs– Termidor -- termites– Regent -- corn– Frontline -- flea & tick– MaxForce FC -- cockroaches and ants

Most lipophilic insecticide ever discoveredPersistent in soilSpread among social insects on bodies4 months of residual on dogs (binds to oils

in sebaceous glands)cross-resistance from cyclodienes

MaxForce FC: Fipronil

• Unique mode of action:– long-term control

– faster results than other ant and cockroach bait products

• Fipronil is a highly active, broad-spectrum insecticide from the phenyl pyrazole family– discovered in 1987

– low doses

– highly effective against a broad range of insect pests, including ants and roaches

Insecticides that Affect the

Nervous System Nervous System

propoxurcarbaryl

permethrindeltamethrin

PyrethroidsDDT

Sodium Channel

abamectin

Avermectins

Glutamate Receptor

chlordaneheptachlor

Cyclodienes

fipronil

Fiproles

GABA Receptor

CarbamatesPhosphates

Imidacloprid

Acetylcholine Receptor

Cholinesterase

chlorpyrifosmalathiondiazinon

Glutamate Receptor in Central Nervous System

• Avermectins– Abamectin

Glutamate-receptors

Glutamate

Glutamate

GlutamateReceptors

Abamectin

Avermectins

• Abamectin– Avert -- cockroaches– Advance -- ants

Produced from soil microbials. Stomach poison for ants and cockroaches

slow actinglow toxicity to mammals

Avert and Advance

• Attractive, long-lasting bait formulations

• Highly effective active ingredient

Insecticides that Affect the

Nervous System Nervous System

propoxurcarbaryl

permethrindeltamethrin

PyrethroidsDDT

Sodium Channel

abamectin

Avermectins

Glutamate Receptor

chlordaneheptachlor

Cyclodienes

fipronil

Fiproles

GABA Receptor

CarbamatesPhosphates

Imidacloprid

Acetylcholine Receptor

Cholinesterase

chlorpyrifosmalathiondiazinon

Why was the brain sent to the principal's office?

It had trouble controlling its impulses

Mitochondrial Energy Disrupters

• Electron transport– Hydramethylnon

• Oxidative phosphorylation– Rotenone– Pyrroles

• chlorfenapyr

– Fluorinated sulfonamids• sulfluramid

Mitochondria

Mitochondria Structures

Energy Production in cells• The chief function of the mitochondria is to create energy by

aerobic respiration. – Glucose is broken down in the cell's cytoplasm to form pyruvic acid

• Krebs Cycle:– Pyruvic acid goes through the Krebs cycle in mitochondria

• Reacts with water to produce carbon dioxide and ten hydrogen atoms

• Electron transport:– Hydrogen atoms are transported on coenzymes to the cristae,

– Hydrogen atoms donated to the electron transport chain.

• Oxidative Phosphorylation -- ADP to ATP

Uh, yeah, Homework Help Line?I need to have you explain the Krebs cycle in roughly the amount of time it takes to get a cup of coffee.

Blockers of Electron Transport

Hydramethylnon

Hydramethylnon• MaxForce -- cockroaches and ants

• Siege -- cockroaches

• Combat -- cockroaches and ants

• Amdro -- fire ants

Yellowish active ingredient that stains. Therefore, it is formulated as bait rather than a spray.

Delayed actionInsects come to a stopUnstable in sunlight

MaxForce: Hydramethylnon

• Powerful delayed-action makes it an ideal active ingredient for bait products. – traditional insecticides affect the nervous system and quickly

produce hyperexcitation and convulsions, – hydramethylnon works gradually as a metabolic poison.

• After a single feeding, no immediate symptoms of poisoning– Within hours, the insects become lethargic and stop eating. – Insects die within 24 to 72 hours. Death caused by inhibiting the

formation of ATP.– Without the formation of ATP, insects simply run out of gas.

Uncouplers of Oxidative Phosphorylation

RotenoneSulfluramidChlorfenapyr

Uncouplers of Oxidative Phosphorylation

• Rotenone -- botanical

• Sulfluramid -- surfactant used originally in floor cleaning compounds

• Pyrroles: chlorfenapyr– new class of insecticides– Trade name: Phantom

FluorGuard: Sulfluramid

• FluorGuard™ Ant Control Baits are effective against a broad spectrum of ants, including:– Argentine Ants – Pharaoh Ants– Pavement Ants – Various Household Ants

Cellular Toxins

• Inorganics– Copper

– Boric acid

– Borax

– Disodium octaborate tetrahydrate

• Fumigants– Sulfuryl fluoride

– Methyl bromide

– Phosphine (aluminum or magnesium phosphide)

– Naphthalene

– Paradichlorobenzene

BORA-CARE or Tim-bor

• Disodium octaborate tetrahydrate – Excellent kill and preventative for wood

destroying organisms

– Applied to bare wood to prevent the home from being a food source for termites.

– Wood treatment eliminates potential soil or water contamination.

Boric Acid Effects

• Action on Human System - Irritant; harms stomach, intestines, blood system, and brain.

• Systemic Effects - Nausea, vomiting, abdominal pain, diarrhea, blood in vomit and feces, headache, weakness, tremors, restlessness.

• Irritation Effects - Irritates and burns skin and respiratory tract.

Vikane: Sulfuryl fluoride

• Proven Effectiveness– More than 30 years of university research, practical use

and published reports.

• Peace-of-Mind Control– Only treatment for drywood termites that effectively

penetrates the entire structure.

• Cost-Effective Option– Fumigation eliminates all existing infestations throughout

the entire structure in one application.

Phostoxin: phosphine

• Used to fumigate– stored food– seed– grain

• DEGESCH operates a manufacturing facility in the beautiful Shenandoah Valley that produces the aluminum phosphide product, Phostoxin.

Cuticular Disrupters

• Silica gel– Amorphous, nonabrasive– Absorbs 3 times its weight in oils and waxes– Insect dehydrates and dies

• Diatomaceous earth– It is fossilized silica remains of diatoms – Both abrasive and absorptive– Absorbs wax layer of insect cuticle, but also works by abrading

the cuticle

Wax Layer

Tri-Die: Silica Gel

• Naturally derived repellent residual dust with contact kill.

• It contains 1% pyrethrum, 10% piperonyl butoxide, and 40% amorphous silica.

Insect Growth Regulators

• Juvenile hormone analogs or mimics

• Chitin inhibitors (benzoylphenyl ureas)

Juvenile Hormone Products

• Methoprene -- not stable in sunlight– Altosid

– PharaohRid

– Extinguish Fire Ant Bait

• Hydroprene -- not stable in sunlight– Gencor

• Pyriproxyfen -- stable in sunlight– Archer

• Neem (azodiractin) -- no good formulations

Cockroach affected by hydroprene

Archer: Pyriproxyfen

• Target Both Cockroaches and Fleas with one IGR – Unique mode of action – Low use rates – Lasting residual activity – Photostable for long-term control

Juvenile Hormone Analog Effects

• Action on Human System - Very low systemic toxicity.

• Systemic Effects - Minimal

Chitin Synthesis Inhibitors (CSI)

• Diflubenzuron (Dimilin)• Hexaflumuron (Recruit bait used in

Sentricon)• Lufenuron (Program)• Affect insect’s ability to molt by

shutting off synthesis of chitin

Normal

CSI affected

Termite workers

Sentricon with Recruit II Bait

• First product approved under the EPA's new Reduced Risk Pesticide Initiative.

• Workers ingest bait and pass it along to other members of the termite colony.

• Impacts termites by inhibiting their molting process

Chitin Synthesis Inhibitor Effects

• Action on Human System - Low systemic toxicity.

• Systemic Effects - Minimal

Modes of Action of Insecticides

Nervous System Energy Production

Cellular Toxins

Cuticular Disrupters

Growth and Metamorphosis

What did the brain say during its retirement speech?

Thanks for the memories