CORE Ch11 Cheat Sheet: Pesticide Application Procedures

🎯 Top 5 Traps

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3 CALIBRATION VARIABLES affect boom sprayer rate: (1) NOZZLE FLOW RATE (orifice + pressure + spray liquid density), (2) GROUND SPEED, (3) WIDTH SPRAYED PER NOZZLE. Application rate varies INVERSELY with ground speed: DOUBLING the speed reduces gallons/acre by HALF. Likewise, doubling effective width per nozzle reduces gallons/acre by HALF. PRESSURE-FLOW relationship is COUNTERINTUITIVE: doubling the pressure does NOT double the flow rate. To DOUBLE flow rate, you must increase pressure 4 TIMES. Pressure can correct MINOR changes from nozzle wear, NOT major rate changes. Exceeding the recommended pressure range increases drift. Electronic rate controllers: doubling speed = fourfold pressure increase to maintain volume. NOZZLES control amount applied, droplet size, distribution, pattern. LARGER droplets minimize drift; SMALLER droplets maximize coverage.

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3 SAFETY SYSTEMS with different roles — and an ENCLOSED CAB is a SUPPLEMENT to PPE, NOT a replacement. CLOSED MIXING/LOADING SYSTEMS: increase handler safety, reduce PPE need, decrease spills, accurate measurement. Two types: MECHANICAL (gravity or suction; minibulks 40 to 330 gallons; available for containers as small as 2.5 gallons) + WATER-SOLUBLE PACKAGING. ENCLOSED CABS: SUPPLEMENT to PPE — must wear all label-specified PPE inside; outside surfaces of cab + equipment are CONTAMINATED, so wear appropriate PPE getting in/out and during maintenance; some labels allow PPE exceptions inside cab. PESTICIDE CONTAINMENT PADS: impermeable material, concave or curbed/bermed/walled, sized to hold the largest spill/leak/wash water expected, sump or pump system to recover material. Required where same site is used repeatedly to mix/load/clean equipment.

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CRITICAL CONVERSIONS + AREA FORMULAS: 1 ACRE = 43,560 SQUARE FEET. 1 GALLON = 128 FLUID OUNCES. RECTANGULAR area = LENGTH x WIDTH. TRIANGULAR area = (BASE x HEIGHT) / 2. CIRCULAR area = 3.14 x r2 (radius = HALF the diameter). RATE CALCULATION FLOW: (1) calibration test gives gallons over a known area; (2) scale up to total application area using cross-multiplication; (3) apply label rate to determine product needed; (4) convert ounces to gallons if needed using 128 oz/gal. Example: 10 gal water over 0.25 acre, 10-acre field, 4 oz product/gal label rate → 400 gallons spray needed → 1,600 oz product → 12.5 gallons of concentrated product.

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DRIFT REDUCTION operational rules — counterintuitive specifics. Use the LARGEST droplets that still provide adequate coverage. AIR-INDUCTION (VENTURI) NOZZLES form larger droplets + fewer fine particles BUT REQUIRE HIGHER PRESSURES (40 to 100 PSI) to be effective — even at higher pressure, dramatically reduce drift. Lower BOOM HEIGHT = less drift; maintain a 1:1 RATIO of boom height above target to nozzle spacing on boom for proper overlap. AVOID high winds, high ground speeds (cause unstable boom + droplet variability), and TEMPERATURE INVERSIONS (small droplets get trapped in stable air; can drift more than 1 mile). DRIFT CONTROL ADDITIVES: some reduce drift 50% to 80% — but some products INCREASE drift potential, and some may reduce coverage and pesticide effectiveness. Test additives before relying on them; never use as the only drift-reducing technique.

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NOZZLE MATERIALS + GRANULAR SPREADER TYPES — wear and precision rules. NOZZLE MATERIALS: brass, aluminum, plastic, stainless steel, hardened stainless steel, ceramic. NEVER use BRASS or ALUMINUM with abrasive materials (wettable powders, dry flowables) — they wear too fast. WEAR-RESISTANT options: PLASTIC, HARDENED STAINLESS STEEL, CERAMIC. Match nozzle screen size to nozzle. GRANULAR SPREADERS: ROTARY (spinning disk or fan throws granules to front and sides — broadcast, larger coverage) vs DROP (sliding gate opens holes in hopper bottom; gravity feed — SUPERIOR FOR PRECISE PLACEMENT). Granular application rate affected by: ground speed, granule SIZE/SHAPE/DENSITY, field terrain, RELATIVE HUMIDITY + AIR TEMPERATURE. When using multiple band applicators, EACH UNIT must be individually calibrated with the specific material to be applied.

🔢 Numbers You Must Know

Number

What It Represents

1 acre = 43,560 sq ft

Critical area conversion. Used to convert field measurements to acres for label-rate application.

1 gallon = 128 fluid oz

Critical volume conversion. Used to convert label rates expressed in ounces per gallon to total product needed.

3 calibration variables

For boom sprayers: (1) nozzle flow rate, (2) ground speed, (3) width sprayed per nozzle. Doubling either ground speed or width per nozzle reduces gallons/acre by HALF.

4x pressure = 2x flow

Pressure-flow relationship: to DOUBLE the flow rate, you must INCREASE pressure 4 times. Doubling pressure does NOT double flow.

About 90 percent

Share of pesticides formulated for SPRAYING. Sprayers are the most common type of pesticide application equipment.

40 to 100 PSI

Pressure range required for AIR-INDUCTION (VENTURI) NOZZLES to be effective. Even at these higher pressures, venturi nozzles dramatically reduce drift compared to standard nozzles at lower pressures.

50 to 80 percent

Drift reduction achievable with some drift control additives — though some products INCREASE drift, and some reduce coverage. Test before relying.

2.5 gallons / 40 to 330 gallons

2.5 gallons = smallest containers compatible with mechanical closed mixing/loading systems. 40 to 330 gallons = minibulk container range (typically returned to dealer for refilling).

6 nozzle materials

Brass, aluminum, plastic, stainless steel, hardened stainless steel, ceramic. NEVER use brass or aluminum with abrasive materials (wettable powders, dry flowables).

13 application methods

Band, basal, broadcast, crack-and-crevice, directed-spray, foliar, rope-wick/wiper, soil application, soil incorporation, soil injection, space treatment, spot treatment, tree injection.

1:1 boom height to nozzle spacing

Recommended ratio for proper spray pattern overlap. Maintains uniformity for most nozzle types.

3.14 (π)

Constant for circular area calculation: Area = 3.14 x r2. Radius = 12 the diameter.

Rectangular area

Length x width. To convert to acres: divide by 43,560.

Triangular area

(Base x height) / 2. To convert to acres: divide by 43,560.

🧮 Critical Formulas + Conversions

1 acre = 43,560 square feet
1 gallon = 128 fluid ounces

Rectangular area: A = length x width
Triangular area: A = (base x height)2
Circular area: A = 3.14 x r2 (radius = 12 diameter)

Application rate flow:
Step 1: From calibration test → gallons per area unit
Step 2: Cross-multiply to scale to total application area
Step 3: Apply label rate to determine product needed
Step 4: Convert ounces to gallons (if needed) using 128 oz/gal

Speed/width effect on rate:
Double the GROUND SPEED → HALF the gallons per acre
Double the WIDTH per nozzle → HALF the gallons per acre
Double the FLOW rate → 4x the pressure required

🔀 Easily Confused

Pair / Group

Distinguishing Feature

Application methods

BAND (parallel strips between/over rows); BROADCAST (uniform across entire area); SPOT (small distinct areas); CRACK-AND-CREVICE (small amounts in cracks — baseboards, cabinets); FOLIAR (leafy parts); BASAL (lower portions of brush/trees); DIRECTED-SPRAY (specifically targeting pests); ROPE-WICK/WIPER (wiped onto weeds); SOIL APPLICATION (on/in soil); SOIL INCORPORATION (tillage/rainfall/irrigation moves it in); SOIL INJECTION (pressure beneath surface); SPACE TREATMENT (enclosed area); TREE INJECTION (under bark).

Closed system vs Enclosed cab vs Containment pad

Closed system: prevents pesticides from contacting handlers during MIXING/LOADING — reduces PPE need. Enclosed cab: surrounds operator during APPLICATION; SUPPLEMENT to PPE, NOT replacement. Containment pad: contains spills/leaks/overflows/wash water at MIX/LOAD/CLEANUP sites.

Closed system: Mechanical vs Water-soluble packaging

Mechanical: interconnected equipment for safe gravity/suction transfer; minibulks 40-330 gal; available for containers as small as 2.5 gal. Water-soluble bags/packaging: premeasured pesticide in dissolvable bag; placed unopened into mix tank; needs adequate dissolution time during mixing.

Hydraulic vs Air-blast vs ULV sprayer

Hydraulic (liquid) sprayer: water/liquid carrier; pressure atomizes spray at nozzle. Air-blast (mist) sprayer: water + AIR as carriers; airstream delivers droplets — fruit trees, vineyards, vegetables, Christmas trees. ULV (ultra-low volume): pesticide direct or with very small carrier volume.

Larger droplets vs Smaller droplets

LARGER droplets: minimize OFF-TARGET DRIFT; preferred for drift reduction. SMALLER droplets: maximize SURFACE COVERAGE of target. Use the LARGEST droplet that provides adequate coverage. Affected by orifice size, pressure, and viscosity.

Rotary vs Drop spreader

Rotary spreader: spinning disk or fan distributes granules to FRONT and SIDES — covers larger area faster. Drop spreader: adjustable sliding gate opens holes in hopper bottom; granules drop by gravity — SUPERIOR for PRECISE PLACEMENT.

Brass/aluminum vs Wear-resistant nozzles

Brass + aluminum: NOT for abrasive materials (wettable powders, dry flowables) — wear too fast. Wear-resistant: plastic, hardened stainless steel, ceramic. Match nozzle material to formulation. Replace worn nozzles.

Doubling speed vs Doubling pressure

Doubling ground speed: halves gallons/acre (inverse linear relationship). Doubling pressure: does NOT double flow rate. To double flow rate, you must increase pressure 4 TIMES.

Pressure: minor wear vs major rate changes

Pressure can be used to CORRECT MINOR changes from nozzle wear. Pressure CANNOT be used to make major changes in application rate. For major rate changes, change nozzle size or ground speed.

Standard nozzles vs Air-induction (venturi) nozzles

Air-induction (venturi) nozzles incorporate AIR into the spray to form an air-fluid mix — larger spray droplets, fewer fine particles, energy to transport droplets. REQUIRE HIGHER pressures: 40 to 100 PSI. Dramatically reduce drift even at higher pressures.

Granular application rate factors

Affected by: ground speed; granule SIZE, SHAPE, and DENSITY; field terrain; relative HUMIDITY; air TEMPERATURE. Each band applicator unit calibrated individually with specific material.

Why calibrate

TOO LITTLE pesticide may fail to control the target pest. TOO MUCH pesticide is ILLEGAL — can damage the treated plant/animal/surface, produce illegal residues, and cause adverse environmental/nontarget effects.

1:1 boom height to nozzle spacing

Maintaining a 1:1 ratio of boom height above target to nozzle spacing on the boom satisfies most overlap requirements. For air-blast sprayers: minimize spraying over canopy top; use minimum airspeed; consider tower sprayers.

Drift control additives caution

Some additives reduce drift 50 to 80 percent. BUT: some products may INCREASE drift potential; some may reduce coverage and pesticide effectiveness. Test thoroughly before relying. NEVER make additives your only drift-reducing technique.

Temperature inversion + spray

Do NOT spray during a temperature inversion. Inversion = stable air (cool air below warm air); small droplets get trapped in cool ground layer and can drift more than 1 mile (see Ch.7). Detection: smoke/dust hangs in air.

⚙️ Application Equipment + Safety Systems Quick Reference

Topic

Description

Key Specifics

Hydraulic sprayer

Water or other liquid carrier for pesticide. Pressure atomizes spray at nozzle. Most common pesticide application equipment.

Range from large agricultural multi-nozzle boom sprayers + power sprayers to manual backpack and hand-held compressed-air sprayers. Nearly 90% of pesticides formulated for spraying.

Air-blast (mist) sprayer

Water + AIR as carriers. Spray droplets formed by nozzles + delivered by airstream.

Used for disease/insect control on fruit trees, vineyards, vegetables, Christmas trees. Minimize spraying over canopy top; use minimum airspeed for canopy penetration; consider tower sprayers.

ULV sprayer

Pesticide applied direct as formulated OR with dramatically reduced carrier volumes.

For specialized concentrated applications. High dermal + inhalation exposure risk (concentrated product applied as fine droplets).

Sprayer tank

Material that does not corrode and is easily cleaned. Watertight cover. Bottom opening for cleaning/draining; large top opening for filling/cleaning.

Agitation system useful for most sprayable formulations — especially wettable powders + dry flowables. Constant mixing produces uniform spray mixture.

Sprayer pump

Produces flow to nozzles + agitation. Corrosion + abrasion resistant.

NEVER operate above manufacturer's pressure or speed. Don't operate dry. Don't restrict flow at inlet/outlet. Pumps depend on spray liquid for lubrication + cooling.

Sprayer nozzles

Control amount applied, droplet formation/size (coverage + drift), distribution, pattern. Orifice size affects droplet size + flow rate.

LARGER droplets minimize drift; SMALLER droplets maximize coverage. Materials: brass, aluminum, plastic, stainless steel, hardened stainless steel, ceramic. Brass + aluminum NOT for abrasives.

Granular: Rotary vs Drop spreader

ROTARY: spinning disk or fan distributes granules to front and sides. DROP: adjustable sliding gate opens holes in hopper bottom; gravity feed.

Drop spreaders SUPERIOR for precise placement. Rate affected by ground speed, granule size/shape/density, terrain, humidity, temperature.

Other application equipment

Rubs, walk-through sprayers, dipping vats (animals); bait dispensers (rodents, insects, predators); foggers (indoor + some outdoor); chemigation (greenhouses + field crops); dusters (small-scale).

Match equipment to pesticide and target pest. Read label first.

Closed mixing/loading: Mechanical

Interconnected equipment for safe gravity/suction transfer of pesticide concentrate from container to application equipment.

Available for containers as small as 2.5 GALLONS. Often used with MINIBULKS (40 to 330 GALLONS) — typically returned to dealer for refilling. Pump-and-drive units with meter for accurate measurement.

Closed mixing/loading: Water-soluble packaging

Premeasured pesticide in water-soluble bag/packet placed unopened into water or fertilizer in mixing tank.

Few manufacturers provide water-soluble bags for small-volume applications. Need ample mixing time for bags to dissolve.

Enclosed cab

Tractor cab, cockpit, or truck/vehicle cab. Surrounds operator and may prevent exposure if doors/hatches/windows kept closed at all times.

SUPPLEMENT to PPE, NOT replacement. Wear all label-specified PPE inside. Outside surfaces of equipment + cab are CONTAMINATED — wear PPE getting in/out and during maintenance. Some labels allow PPE exceptions inside cab.

Pesticide containment pad

Contains spills, leaks, overflows, wash water at mix/load/cleanup sites for reuse or commercial waste disposal.

Impermeable material; concave or curbs/berms/walls high enough to hold largest spill; sump or pump system to recover material. Permanent installation for repeated use; portable/lightweight plastic trays for application sites.

📐 Calibration + Calculations + Drift Reduction Quick Reference

Topic

Rule

Key Specifics

Calibration purpose

Ensure equipment applies the correct amount of pesticide UNIFORMLY over a given area.

Too little = fails to control pest. Too much = ILLEGAL + damage + illegal residues + environmental harm. Make trial run on premeasured area with WATER (same pressure + technique as actual application).

3 calibration variables (boom sprayer)

(1) Nozzle flow rate — varies with orifice size, pressure, density of spray liquid. (2) Ground speed. (3) Width sprayed per nozzle.

Application rate varies INVERSELY with ground speed: doubling speed = HALF the gallons/acre. Same for width per nozzle. Calibration affects cost, efficiency, safety.

Pressure-flow relationship

Doubling pressure does NOT double flow rate. To DOUBLE flow rate, must INCREASE pressure 4 TIMES.

Pressure can correct MINOR changes from nozzle wear, NOT major rate changes. Exceeding recommended pressure increases drift. Adjust nozzles per manufacturer for nozzle spacing + spray angle.

Electronic rate controllers

Designed to make application volumes more uniform as sprayer speed changes.

Major speed changes affect pressure: doubling speed = fourfold pressure increase to maintain volume. Increased pressure without changing nozzle orifice size dramatically increases drift potential.

1 acre = 43,560 sq ft

Critical conversion. Use to convert area in square feet to acres.

Used in all label rate calculations involving "per acre" rates.

1 gallon = 128 fl oz

Critical conversion. Use to convert ounces of product to gallons.

Used to calculate amount of concentrate needed when label rate is in oz/gal.

Rectangular area

A = length x width

1,320 ft x 120 ft = 158,400 sq ft = 3.6 acres (158,400 / 43,560)

Triangular area

A = (base x height)2

325 ft x 150 ft / 2 = 24,375 sq ft = 0.6 acres

Circular area

A = 3.14 x r2 (radius = 12 diameter)

90 ft diameter → r = 45 ft. 3.14 x 452 = 6,358.5 sq ft = 0.15 acres

Application rate calculation

(1) Use calibration test data; (2) cross-multiply to scale to total application area; (3) apply label rate; (4) convert oz to gal if needed.

Example: 10 gal/0.25 acre x 10 acres = 400 gallons spray needed. 400 gal x 4 oz/gal label = 1,600 oz product. 1,600/128 = 12.5 gallons concentrate.

Drift reduction: Larger droplets

Use the LARGEST droplet size that still provides adequate coverage at intended application volume + pressure.

Air-induction (venturi) nozzles form larger droplets + fewer fine particles. Require 40 to 100 PSI to be effective.

Drift reduction: Boom height

Lower boom = less drift. Maintain 1:1 ratio of boom height above target to nozzle spacing on boom for proper overlap.

Lowering boom a few inches can reduce drift. Air-blast: minimize spraying over canopy top; use minimum airspeed; consider tower sprayers.

Drift reduction: Ground speed

Maintain appropriate travel speed. Avoid high speeds + major speed changes.

High speeds: unstable boom, high boom positions, increased drift. Speed changes cause pressure adjustments → droplet size variability.

Drift reduction: Weather

Avoid high winds. Do NOT spray during temperature inversions.

Inversions trap small droplets in stable air; can drift more than 1 mile (see Ch.7). High winds move spray volume off-target.

Drift reduction: Buffers + additives

Buffer/no-spray zones if sensitive areas downwind. Drift control additives only as one tool among many.

Some additives reduce drift 50 to 80 percent — but some INCREASE drift potential and some reduce coverage. Test before relying. Never the only drift-reducing technique.

💡 Memory Hooks

Critical area conversion: "1 acre equals 43,560 square feet." The most-used number in application math.

Critical volume conversion: "1 gallon equals 128 fluid ounces." The second-most-used number.

3 calibration variables: "Nozzle flow rate, ground speed, width per nozzle." For boom sprayers.

Speed-rate inverse: "Double the speed, half the rate." Doubling either ground speed or width halves gallons/acre.

Pressure-flow trap: "Four times the pressure to double the flow." Counterintuitive math.

Pressure use limit: "Pressure can fix minor wear, not major rate changes." Use ground speed or nozzle changes for major adjustments.

Larger droplets win: "Larger droplets drift less." But too large reduces coverage.

Spray dominance: "About 90 percent of pesticides are sprayed." Why sprayer knowledge matters.

Spreader rule: "Drop spreaders for precision; rotary for area." Choose by placement need.

Nozzle materials: "Brass and aluminum — never with abrasives." Wettable powders + dry flowables wear them too fast.

Venturi pressure: "Air-induction nozzles need 40 to 100 PSI." Higher pressure required for effectiveness.

Closed system vs cab: "Closed system reduces PPE need; enclosed cab does not replace it." Different roles.

Cab-exterior contamination: "Outside of the cab is contaminated." PPE still required getting in/out and for maintenance.

Boom overlap: "1:1 ratio of boom height to nozzle spacing." Standard overlap for most nozzle types.

Drift additive caution: "Some reduce drift 50 to 80 percent — but some increase it." Test before relying.

Granular variables: "Granules: speed, size, shape, density, terrain, humidity, temperature." Many factors affect rate.

Ch.11: Pesticide Application Procedures