CORE Ch4 Cheat Sheet: Pesticide Formulations

🎯 Top 5 Traps

1

BRAND NAME NUMBERS often indicate active ingredient content. ACTIVE ingredient controls the pest; INERT ingredient has NO pesticidal activity (carriers, surfactants, stabilizers, dyes). Examples: 80WDG = 80% a.i. by weight (a 10-lb bag = 8 lb a.i. + 2 lb inert); 4F = 4 pounds of a.i. per gallon in a flowable. Active ingredients must be listed by chemical and/or common name with percentage. Inert ingredients are usually NOT named, but the label must show the percentage they make up.

2

Liquid pesticides come as 3 mixture types — and they behave very differently: SOLUTION (true mixture; dissolves; transparent; NO agitation needed; sweetened tea), SUSPENSION (solid particles dispersed in liquid; cloudy/opaque; requires CONSTANT mechanical agitation; flour and water), EMULSION (oil droplets in water OR vice versa; "milky" appearance; emulsifiers prevent separation; homogenized milk). Emulsifiable Concentrate (EC) becomes an emulsion when mixed with water. Most ECs contain 2-6 pounds a.i. per gallon.

3

WETTABLE POWDERS (WP) form SUSPENSIONS — require CONSTANT MECHANICAL agitation and settle out quickly without it. SOLUBLE POWDERS (SP) form true SOLUTIONS — only inhalation hazard during mixing. WATER-DISPERSIBLE GRANULES (WDG) / DRY FLOWABLES (DF) = wettable powder compressed into dust-free granule-sized particles for REDUCED HANDLER EXPOSURE. Both WP (5-95% a.i., usually 50%+) and SP (15-95% a.i., usually 50%+) carry the inhalation risk during mixing. WP particles do NOT dissolve in water — they remain on the treated surface even on porous materials like concrete. Few active ingredients dissolve in water, so SP is uncommon.

4

EMULSIFIABLE CONCENTRATES (EC) and ULTRA-LOW VOLUME (ULV) are HIGH-EXPOSURE concentrated formulations. EC: 2-6 lbs a.i./gal; petroleum solvents cause rubber/plastic deterioration; EASILY ABSORBED THROUGH SKIN; flammable; strong odor; may cause phytotoxicity. ULV: ALMOST 100% a.i.; very fine droplet drift hazard; HIGH dermal AND inhalation exposure risk; specialized equipment required; calibration must be performed with special care. Both share solvent-based equipment damage. INVERT EMULSIONS reverse the chemistry (water-soluble pesticide in oil carrier; mayonnaise consistency) for LOW DRIFT — used mostly for rights-of-way weed control.

5

SURFACTANTS come in 3 types — choose by pesticide mechanism: ANIONIC (negative charge — for CONTACT pesticides); CATIONIC (positive charge — DO NOT use as stand-alone, often PHYTOTOXIC); NONIONIC (no charge — for SYSTEMIC pesticides; helps penetrate plant cuticles; most compatible). Wrong surfactant = reduced efficacy + damaged plants/surfaces. ALL surfactants are adjuvants, but NOT all adjuvants are surfactants (drift control additives + safeners are adjuvants but not surfactants). EPA does NOT register adjuvants — there are NO standards for composition, quality, or performance. Use only adjuvants made for agricultural/horticultural use; never industrial products or household detergents.

🔢 Numbers You Must Know

Number

What It Represents

3 liquid mixture types

Solution (transparent, no agitation, dissolves); Suspension (cloudy, constant agitation, particles dispersed); Emulsion (milky, droplets of one liquid in another)

3 surfactant types

Anionic (negative charge — contact pesticides); Cationic (positive charge — DO NOT use stand-alone, phytotoxic); Nonionic (no charge — systemic pesticides, most compatible)

2 to 6 lbs a.i./gallon

Typical Emulsifiable Concentrate (EC) active ingredient content

Almost 100% a.i.

Ultra-Low Volume (ULV) concentrate — designed to be used as-is or diluted with small quantities of specified solvents; very fine droplets at very low rates

1% or less per unit volume

Typical RTU (ready-to-use) low-concentrate solutions — often packaged with application device

5% to 95% a.i. (usually 50%+)

Wettable Powder (WP) active ingredient range

15% to 95% a.i. (usually 50%+)

Soluble Powder (SP) active ingredient range

1% to 15% a.i.

Granule (G) active ingredient range

10% or less a.i.

Typical Dust (D) active ingredient (some concentrate dusts higher and must be mixed with dry inert carriers before application)

Less than 5% a.i.

Typical Bait (B) active ingredient — pest goes to bait, so entire area need not be covered

5 to 10 lbs

Capacity of refillable commercial RTU aerosol units

pH 5.5 to 7.0

Range in which most pesticide solutions/suspensions are stable; outside this range, water may cause rapid pesticide degradation. Add buffers FIRST.

Brand name decoders

80WDG = 80% a.i. as water-dispersible granule (10-lb bag = 8 lb a.i. + 2 lb inert). 4F = 4 lbs a.i./gallon flowable. 5G = 5% a.i. granule.

🔀 Easily Confused

Pair / Group

Distinguishing Feature

Active vs Inert ingredients

Active: chemical(s) responsible for the pesticidal activity — must be listed with chemical/common name + percentage. Inert: NO pesticidal activity — usually NOT named on label, but percentage must be shown. Includes carriers/diluents (clay, talc), surface-active ingredients (stickers, spreaders), stabilizers, dyes.

Solution vs Suspension vs Emulsion

Solution: substance dissolves in liquid; transparent; NO settling/agitation needed (sweetened tea). Suspension: fine solid particles dispersed in liquid; cloudy/opaque; CONSTANT agitation required (flour and water). Emulsion: droplets of one liquid suspended in another; "milky" appearance; emulsifiers prevent separation; EC becomes emulsion when mixed with water (homogenized milk).

Concentrate vs Ready-to-Use

Concentrate: must be mixed/diluted before use. Less expensive per treatment, but MORE TOXIC, more handling required, HIGHER EXPOSURE RISK. Ready-to-use: applied with no further dilution. Convenient, less personal exposure, but limited availability and high cost per unit a.i.

Wettable Powder (WP) vs Soluble Powder (SP)

WP: particles do NOT dissolve in water — form a SUSPENSION; require CONSTANT MECHANICAL agitation; settle out quickly; particles remain on treated surface (even on porous concrete/plaster/wood). SP: particles DISSOLVE in water — form true SOLUTION; only inhalation hazard during mixing; few active ingredients dissolve in water, so SP is uncommon.

Wettable Powder (WP) vs Water-Dispersible Granule (WDG/DF)

WDG/DF is wettable powder COMPRESSED into dust-free granule-sized particles. Same advantages and disadvantages of WP, plus REDUCED HANDLER EXPOSURE because they are larger, less dusty particles, and easier to remove from container and measure. Both require constant agitation in spray tank.

Granules (G) vs Pellets (P/PS)

Granules: irregular sizes/shapes and density; absorbed onto carriers like clay or ground corncobs; humidity affects flow; CALIBRATE OFTEN. Pellets: all particles MORE OR LESS THE SAME WEIGHT AND SHAPE (extruded under pressure, cut to length); apply with PRECISION; often used for spot treatments. Some fumigants are pellets.

Dust (D) vs Granule (G)

Dust: very fine inert carrier (talc, chalk, clay, nut hulls, volcanic ash); high drift; high inhalation hazard. Granule: larger, heavier particles; LOW drift; particles settle quickly; weight carries the formulation through foliage to soil/water target.

Tracking powders (toxic) vs Tracking patches (nontoxic)

Tracking POWDERS: finely ground dusts with adsorbed STOMACH POISON — insect/rodent picks up and ingests when grooming; effective when bait acceptance is poor (food abundant). Tracking PATCHES: NONTOXIC dust like talc/flour/limestone — used to monitor and track activity (not kill). Don't confuse the two.

Emulsifiable Concentrate (EC) vs Invert Emulsion

EC: oil-soluble a.i. in petroleum solvent + mixing agent — emulsifies in water. Versatile but flammable, easily absorbed through skin, equipment damage, possible phytotoxicity. Invert Emulsion: WATER-SOLUBLE pesticide dispersed in OIL carrier (usually fuel oil); thick mayonnaise consistency; LOW DRIFT (oil evaporates slowly); large droplets; rights-of-way weed control.

ULV vs RTU low-concentrate

ULV (Ultra-Low Volume): ALMOST 100% a.i.; concentrated; HIGH drift hazard; specialized equipment; high dermal/inhalation exposure. RTU low-concentrate: 1% or less a.i.; NO mixing; convenient; reduced exposure; limited availability; high cost per unit a.i.

RTU Aerosol vs Smoke/Fog Generator formulations

RTU aerosol: pressurized sealed container; inert pressurized gas pushes pesticide through fine opening; small contained spaces. Smoke/fog generator: NOT under pressure; placed in machines with rapidly whirling disk or heated surface; very fine droplets/fog; greenhouses, barns, warehouses, outdoor mosquito control.

Adjuvant vs Surfactant

Adjuvant: ANY substance added to modify properties of pesticide formulation or finished spray. Surfactant: SPECIFIC kind of adjuvant — alters dispersing/spreading/wetting properties (changes surface tension of spray droplets). All surfactants are adjuvants, but drift control additives + safeners + buffers are adjuvants that are NOT surfactants.

Anionic vs Cationic vs Nonionic surfactants

Anionic: negative charge — for CONTACT pesticides. Cationic: positive charge — DO NOT use stand-alone (often phytotoxic). Nonionic: no electrical charge — for SYSTEMIC products; helps penetrate plant cuticles; compatible with most pesticide products.

EPA registration: Pesticides vs Adjuvants

Pesticides MUST be registered. Adjuvants are NOT registered — there are NO standards for composition, quality, or performance. Only use adjuvants made for agricultural/horticultural use; never substitute industrial products or household detergents in pesticide spray mixes.

Tank mixing rules

Federal law allows applicators to combine pesticides UNLESS the labeling of one or more components specifically prohibits it. When mixed, ALL DOSAGES must be at or BELOW the label rate for each separate component. Pesticide-fertilizer combinations also allowed (often premixed in granule/pellet formulations).

🧪 Common Pesticide Formulations Quick Reference

Formulation (Abbrev.)

Properties / a.i.

Key Pros / Cons

Emulsifiable Concentrate (E or EC)

2-6 lbs a.i./gal in petroleum solvent + mixing agent. Becomes emulsion in water. Versatile.

+ Easy to handle/measure; little agitation; not abrasive. - Easily ABSORBED THROUGH SKIN; flammable; equipment damage from solvents; possible phytotoxicity; strong odor.

Solution (S, C, LC, WSC, WSL)

True solution in solvent (water, oil). RTU = 1% or less a.i. Concentrate = label-specified dilution.

+ No agitation; not abrasive; no clogged nozzles. - Some easily absorbed through skin; spills hard to clean.

Ultra-Low Volume (ULV)

ALMOST 100% a.i. Very fine droplets at very low rates per unit area.

+ Easy storage; not abrasive. - HIGH DRIFT HAZARD; specialized equipment; high dermal + inhalation exposure; equipment damage from solvents.

Invert Emulsion

Water-soluble pesticide in OIL carrier. Mayonnaise consistency. Large droplets. Mostly for rights-of-way weed control.

+ LOW DRIFT (oil evaporates slowly); good rainfastness; reduced runoff. - Large droplets hard to direct under foliage; limited availability.

Flowable (F or AF)

Insoluble solids ground fine, suspended in liquid. Thick liquid suspension. Often used like ECs.

+ Easy to apply; low exposure risk; not phytotoxic; rarely clog nozzles. - Need shaking; abrasive; difficult to rinse container.

RTU Aerosol (A)

Pressurized sealed container. Pressurized gas pushes pesticide through nozzle. Commercial models 5-10 lbs.

+ Convenient; portable; retains potency. - Inhalation risk; hazardous if punctured/overheated; difficult to direct.

Dust (D)

Usually 10% or less a.i. on fine inert carrier (talc, chalk, clay, nut hulls, volcanic ash). Always used dry.

+ No mixing; good for cracks/crevices, ectoparasites; no moisture damage. - HIGH drift; HIGH inhalation hazard; eye/nose/throat irritation; uneven distribution.

Granule (G)

1-15% a.i. on coarse adsorptive/absorptive carrier (clay, ground corncobs, walnut shells). Slow release. Mostly soil applications.

+ LOW drift; particles settle quickly; carries through foliage. - Needs frequent calibration; doesn't stick to foliage; may need moisture; HAZARDOUS to BIRDS (mistake for grit).

Pellet (P or PS)

Like granules, but UNIFORM weight/shape (extruded). Apply with precision. Often spot treatments. Some fumigants.

+ Precise application. - Bulky; low % a.i. per unit volume; limited foliar adhesion.

Wettable Powder (WP or W)

5-95% a.i. (usually 50%+). Forms SUSPENSION in water; particles do NOT dissolve. Constant mechanical agitation required.

+ Less skin absorption than EC; not phytotoxic; remains on porous surfaces. - INHALATION hazard during mixing; abrasive; clogs nozzles; visible residue; settles quickly.

Water-Dispersible Granule / Dry Flowable (WDG/DF)

WP compressed into dust-free granule-sized particles. Same as WP but reduced exposure risk.

+ Less dusty + easier to measure than WP; constant agitation in tank still required.

Soluble Powder (SP or WSP)

15-95% a.i. (usually 50%+). DISSOLVES in water — true solution. Few active ingredients dissolve so SP uncommon.

+ All advantages of WP; only inhalation hazard during mixing; no agitation after dissolved.

Bait (B) — Solid + Pastes/Gels

Less than 5% a.i. mixed with attractant. Solid (blocks/granules/pellets), liquid, paste, or gel. Pastes/gels primary cockroach control.

+ RTU; pest goes to bait; controls moving pests. - Attractive to children/pets; require careful placement; nontarget hazards; dead vertebrate odor.

Microencapsulated (M)

Coated dry particles or droplets. Mix with water and spray. Coating provides timed release. May be weather-dependent.

+ Coatings protect applicator; timed release prolongs effectiveness; reduced volatility/odor/staining. - Bee hazard if particle size matches pollen; LONG REI/PHI for highly toxic products; agitation may be needed.

Fumigant

Active ingredient delivered as a GAS. Liquids under pressure, volatile liquids, or solids releasing gas in humidity/water. Structural, food storage, soil, regulatory.

+ Penetrates cracks/crevices/wood/soil; single treatment kills most pests. - Target site must be ENCLOSED; nonspecific + highly toxic to ALL organisms; HIGH inhalation risk; specialized PPE + equipment.

Water-Soluble Packaging (WSB or WSP)

Special film bag dissolves in spray tank water releasing pesticide. Premeasured doses.

+ ACCURATE PREMEASURED unit doses; greatly reduced handler exposure; lower spill risk. - Won't dissolve in organic solvents/undiluted ECs; must be kept DRY (don't handle with damp gloves).

🧴 Adjuvants + Surfactants Quick Reference

Type

Function

Notes

Antifoaming agent

Reduces foaming of spray mixtures from surfactants and/or vigorous agitation.

Useful when other adjuvants cause foaming.

Buffer / pH modifier

Allows pesticides to be mixed with diluents or other pesticides of different acidity/alkalinity.

Most pesticide solutions stable pH 5.5-7.0 (slightly acidic to neutral). Add buffer to spray tank water FIRST and mix well — water must be neutral or slightly acidic before adding pesticides.

Compatibility agent

Helps combine pesticides (or pesticides and fertilizers) effectively; reduces incompatibility.

Used for tank mixes that would otherwise separate.

Drift control additive (deposition aid)

Reduces drift; increases average droplet size and/or lowers number of "fines" (very small droplets).

Adjuvant but NOT a surfactant.

Emulsifier

Allows petroleum-based pesticides (ECs) to mix with water.

Often built into EC formulations.

Extender / Sticker

Keep pesticides active on a target for an extended period. Stickers increase adhesion to treated surface. Some reduce evaporation or slow photodegradation.

Reduces wash-off due to rain or irrigation. Some manufacturers use "extender" and "sticker" interchangeably.

Invert emulsifier

Allows water-based pesticides to mix with petroleum carrier.

Used for invert emulsions (mayonnaise consistency, low drift).

Plant penetrant

Allows pesticide to pass through outer surface to inside of treated foliage.

May increase penetration on some plant species but not all.

Safener

Reduces toxicity of pesticide formulation to the handler or to the treated surface.

Adjuvant but NOT a surfactant.

Spreader

Allows pesticide to form uniform coating layer over treated surface.

A type of surfactant.

Thickener

Increases viscosity (thickness) of spray mixtures.

Reduces drift and/or slows evaporation. Useful with systemic pesticides — gives more time for absorption.

Wetting agent

Allows wettable powders to mix with water.

A type of surfactant.

Surfactant: ANIONIC

Negative charge.

Most often used with CONTACT pesticides (work by direct contact, not absorbed systemically).

Surfactant: CATIONIC

Positive charge.

DO NOT use as stand-alone — often PHYTOTOXIC.

Surfactant: NONIONIC

No electrical charge.

Often used with SYSTEMIC products; helps sprays penetrate plant cuticles; compatible with MOST pesticide products.

💡 Memory Hooks

Active vs inert: "Active controls; inert carries." Active controls the pest; inert serves as carrier, surfactant, or stabilizer.

Three liquid types: "Solution dissolves; suspension settles; emulsion looks milky." The three liquid mixture forms.

Brand-name math: "80WDG = 80% a.i. by weight; 4F = 4 lbs a.i./gallon." Numbers in product names tell you the active content.

WP vs SP: "WP needs constant agitation; SP dissolves once mixed." Two powders, one suspension and one solution.

WDG benefit: "WDG is WP without the dust." Reduced handler exposure from compressed dust-free particles.

EC trade-off: "Easy to use, hard on equipment." Convenient mixing, but solvents damage rubber/plastic and absorb through skin.

ULV warning: "Almost 100% a.i. — drift hazard high." Concentrated formulation requires special equipment and special care.

Surfactant rule of thumb: "Anionic for contact; nonionic for systemic; cationic never alone." Three surfactant types and their uses.

EPA + adjuvants: "EPA does not register adjuvants." No standards for composition, quality, or performance.

Buffer order: "Buffer first, pesticide second." Water must be pH neutral or slightly acidic before adding pesticide.

Granules vs pellets: "Granules vary; pellets are uniform." Pellets are extruded to consistent shape and weight.

Tank mix rule: "Legal unless prohibited; all dosages at or below label rate." Federal default.

Tracking distinction: "Tracking POWDER kills; tracking PATCH detects." Toxic vs nontoxic dust.