CORE Ch10 Study Guide: Planning the Pesticide Application

Learning Objectives

After studying this chapter, you should be able to:

Select appropriate pesticides and additives.
Follow label instructions and legal restrictions.
Determine whether two or more pesticides can be tank-mixed.
Follow label directions for safe mixing and loading.
Prevent water source contamination during mixing, loading, and cleaning.
Select appropriate PPE for mixing, loading, cleaning.
Open containers and transfer contents safely.
Measure pesticides accurately.
Rinse and dispose of pesticide containers properly.
Apply pesticides correctly.
Clean and store equipment.
Demonstrate professionalism.

Selecting the Pesticide & Reviewing the Label

Before buying or applying, read the label to determine:

Safety measures to follow.
Where it can legally be used (target sites).
When to apply it — life cycle of pest, weather, preharvest/grazing interval, rotational/replanting interval.
How to apply it — equipment setup, label directions.
Special use restrictions (REI, prohibited methods).
Environmental restrictions, setbacks, drift warnings.

The "Directions for Use" section lists crops/animals/sites, target pests, application rates, spray quality (droplet size) specs, and application methods. Also consult sprayer cleanout, storage, and disposal directions.

Pesticide Compatibility

Compatible = two or more pesticides can be mixed and applied together without reducing effectiveness or changing physical/chemical properties of the mixture.

Two Types of Incompatibility

Physical Incompatibility

Chemical Incompatibility

Products don't stay uniformly mixed. Signs: putty/paste formation, separation into layers, cottage-cheese appearance (precipitates). Clogs screens and nozzles.

A chemical reaction occurs that produces new substances. Signs: heat, color change, gas or precipitate formation, surface scum or foam, gel or "sludge."

Causes of Physical Incompatibility

Improper mixing procedures.
Inadequate agitation.
Lack of stable emulsifiers in some ECs.
Mixing with liquid fertilizers.
Mixing with hard water (pH > 7).

🎯 Trick Spot: Cottage cheese appearance = physical incompatibility (precipitates). Heat, gas, color change = chemical incompatibility (a reaction is happening).

Chemical Incompatibility — Two Kinds

Activity of one or more components is reduced when mixed.
Combined activity is greater than either product alone — may damage target plants because selectivity is weakened.

Signal-Word Rule for Mixes

If a tank mix contains a pesticide with a higher toxicity level (DANGER) than the others (WARNING or CAUTION), treat the entire mixture according to the more restrictive signal word (as a DANGER pesticide). Use the required safety equipment and follow all label requirements of the most restrictive product.

⚠️ Exam Tip: It is illegal to mix pesticides with other products when the label expressly prohibits such mixtures.

Conducting a Jar (Compatibility) Test

If unsure whether products can be tank-mixed, do a jar test with a small amount first:

Fill jar one-fifth to one-half full with the carrier (water or liquid fertilizer).
Add proportionate amounts of each product, one at a time, in the recommended tank mix order.
Shake thoroughly after each addition.
Let stand for 10 to 15 minutes.
Look for problems.

🎯 Trick Spot: Fail signs include flakes, sludge, gel, precipitates, other solids, layer separation, OR heat being given off. If you see any of these, the products cannot be safely tank-mixed. Compatibility agents may help in some cases.

Tank Mixing Order

Always follow this sequence:

Fill tank one-fifth to one-half full with carrier (water or liquid fertilizer). Start agitation.
Add compatibility agent (if needed).
Add suspension products: dry first (WP, DF, WDG as preslurry if needed), then liquids (F, L, ME).
Add solution products (S, SP).
Add surfactants or other adjuvants (if needed).
Last: add emulsion products (EC).

For dry formulations, make a preslurry — mix with a little water to form a paste — before adding. Keep agitation running through the entire application until the tank is empty.

Safe Mixing & Loading Practices

Mixers and loaders have an especially high risk of accidental exposure and poisoning.

Location

Well-ventilated (if indoors), well-lit, away from people, animals, food, and items that might be contaminated.

Protect Water Sources

Keep the water pipe/hose end well above the pesticide mixture surface — maintain an air gap.
If pumping water directly from a source: use a check valve, anti-siphoning device, or backflow preventer.
Check valves are crucial for chemigation — pesticide injected into irrigation water.
Mix in areas where spills/leaks/overflows cannot flow into drains or water.
Use a containment pad for permanent mix/load sites.
When possible, mix/load at the application site. Don't use the same site repeatedly.

PPE for Mixing and Loading

Body: bib-top apron (butyl, nitrile, or foil-laminate) for splash protection. Built-in gloves/sleeves are even better.
Face: face shield against splashes and dusts.
Respiratory: label-specified NIOSH respirator.
Eyes: shielded safety glasses, goggles, or face shield.

Opening Containers & Measuring

Opening

Do not tear open paper or cardboard containers — use a sharp knife or scissors.
Clean the knife/scissors after use. Don't use them for other purposes.
Close containers after each use, even if you'll add more of the same product.

Measuring Accurately

Liquids and some granulars = measured by volume (fluid ounces, pints, quarts, gallons).
Dusts, powders, and most dry formulations = measured by weight (pounds, ounces).
Use glass or plastic measuring utensils. Pesticide labels use the English measurement system.

🎯 Trick Spot: Some pesticides react with metal — especially aluminum and iron. Avoid metal measuring utensils; use glass or plastic instead.

Mark each measuring item clearly (bright waterproof paint or labels).
Clean utensils after each use.
Keep measuring equipment locked in the pesticide storage area when not in use.

Transferring Pesticides

Keep the container and pesticide below face level when pouring.
Stand so wind/air currents won't blow pesticide back on you.
Rinse the measuring container and pour the rinsate into the spray tank.
Never leave the spray tank unattended while filling.

Cleaning & Disposing of Containers

Follow the container-handling instructions on the label. Not all containers must be triple-rinsed or pressure-rinsed — but if rinsing is required, rinse immediately after emptying (residues dry and become hard to remove). Add rinsate to the next application when possible.

Refillable Container

Nonrefillable Container

Label tells you to return to the dealer/manufacturer for refilling. Never tamper with these.

Label will tell you whether to recycle, recondition, or dispose of it. Never reuse pesticide containers.

Triple-Rinsing Small Containers (≤5 gallons)

Empty contents into application equipment or mix tank — drain 10 seconds after flow begins to drip.
Fill container one-quarter full with water. Recap.
Shake for 10 seconds.
Pour rinsate into equipment or store for later. Drain 10 seconds.
Repeat two more times.

Larger Containers (>5 gallons or >50 pounds)

Empty contents.
Fill one-quarter full with water and tighten closures.
Tip on side; roll back and forth at least one complete revolution for 30 seconds.
Stand on end; tip back and forth several times. Flip and repeat on other end.
Empty rinsate. Repeat twice more.

Pressure Rinsing

Hold container upside down; insert pressure-rinsing nozzle in the side; rinse at about 40 psi for at least 30 seconds. Drain 10 seconds.

⚠️ Exam Tip: Triple-rinsing and pressure-rinsing are both acceptable. Rinsate from either method may be stored for later use or added to application equipment.

Recycle empty containers through the Ag Container Recycling Council or your state program where available.

Applying Pesticides Correctly

Hand-Carried & Backpack

Dripping or clogged nozzles, leaky hoses, loose connections are common exposure sources.
Whenever possible, apply so you are backing out of the treated area.
Consider shin-high or knee-high rubber boots with spray-resistant pants when walking into spray paths.

High-Exposure Applications

Especially risky — wear gloves, protective coveralls with hood, footwear with sealed cuffs, and a full-face or half-face respirator with sealed goggles:

Mist blower or air-blast sprayers.
Aerosol and fog generators.
High-pressure sprayers and power dusters.
Overhead applications (tree canopies, roof eaves).
Enclosed spaces (warehouses, factories, railcars, silos, greenhouses) — wear respirator and extra clothing even if you wouldn't need them outdoors.

Application Procedure

Clear all people and pets. Remove toys, pet dishes. Cover garden furniture, pools, birdbaths.
Ensure the pesticide is reaching the target (sweep granules from sidewalks and nontarget areas).
Apply evenly, in correct amounts — no puddling or piling. Careful at turns/pauses; shut off equipment when you pause.
Maintain uniform mix — agitation for suspensions.
Check hoses, valves, nozzles, hoppers often.
When pausing, depressurize spray tanks: turn off main pressure valve and release pressure at nozzles.
Check label for post-application requirements (e.g., soil incorporation).

🎯 Trick Spot: Even for narrow applications like crack-and-crevice treatments, keep people and animals out of the immediate area during the application. If the label doesn't give a specific REI, wait until spray has dried or dust has settled.

Cleaning Equipment & Handling Rinsates

PPE for Cleanup

Wear the same PPE the label requires for applications, plus a chemical-resistant apron or other protection. Equipment cleaning is as risky as other handling tasks.

Rinsate Rules

Equipment rinsate may be used as diluent for future mixes only if:

Pesticide in rinsate is labeled for the new target site.
Combined rinsate + new product does not exceed label rate.
Mixing the rinsate with the new pesticide is compatible.

🎯 Trick Spot: Rinsate may not be added to a pesticide mixture if it contains strong cleaning agents (bleach, ammonia) or if it would make the mix unusable (physically or chemically incompatible). If rinsate can't be reused, dispose per label (treat as waste pesticide).

Equipment Cleanup Procedure

Clean after each use or when changing chemicals.
Clean entire spray system, not just the tank — including eductor, plumbing, valves, hoses, filters, screens, boom segments, nozzle bodies, and nozzles.
Water-detergent rinse: 8–16 oz detergent in 30–40 gal water; circulate for several minutes.
Remove nozzles and screens; flush sprayer twice with clean water.
Some labels require triple rinsing of the spray system.
Remove all visible deposits.

Storage Prep

Before storage, add 1–5 gallons of lightweight oil before final flushing. Oil coats interior of tank, pump, and plumbing.
Remove nozzle tips and screens; store in a can of diesel or kerosene.
Rotate pump four or five revolutions by hand with a small amount of oil.
Winterize: drain all water or replace with antifreeze (RV antifreeze is common).
Store equipment in a dry, clean building. Replace worn parts.
After cleaning equipment, remove contaminated clothes and shower immediately — waiting lets more pesticide absorb through skin.

Professionalism

Professionalism = "the skill, good judgment, and polite behavior expected from a person trained to do a job well." Core elements:

Fair treatment of customers.
Respect for others.
Being an asset to your community.
Ethical behavior — no shortcuts that harm people or the environment.
IPM thinking — apply only when needed, protect sensitive sites.
Use clear language, not jargon, when talking to customers and the public.
Know your company's media/customer communication policies.
Keep accurate records — your best defense against complaints or legal action.

Key Terms Cheat Sheet

Compatibility: Can be mixed and applied without losing effectiveness or changing properties.

Physical incompatibility: Won't stay mixed — paste, layers, cottage cheese. Causes: bad mixing, low agitation, weak emulsifiers, liquid fertilizers, hard water (pH > 7).

Chemical incompatibility: Reaction — heat, color change, gas, precipitate, scum, foam, gel, sludge.

Jar (Compatibility) Test: 1/5–1/2 full jar with carrier; add in tank-mix order; shake; let stand 10–15 min; look for problems.

Tank Mixing Order: Carrier → compatibility agent → suspensions (dry WP/DF/WDG first, then liquids F/L/ME) → solutions (S, SP) → surfactants/adjuvants → emulsions (EC LAST).

Preslurry: Dry formulation mixed with small amount of water into a paste before adding to tank.

Signal Word Rule: Tank mix takes on the most restrictive signal word in the mix (DANGER beats WARNING beats CAUTION).

Air gap: Space between water discharge and pesticide surface — prevents back-siphoning.

Check valve / Backflow preventer: Mechanical device that closes if water pressure drops.

Chemigation: Pesticide injected into irrigation water — check valves are crucial.

Metal utensils: Avoid (especially aluminum and iron) — many pesticides react with them. Use glass or plastic.

Liquids/granules: measured by volume. Dusts/powders/dry: measured by weight.

Triple-rinsing small containers: empty + 10 sec drain; 1/4 full water; shake 10 sec; pour out; repeat 2× more.

Larger containers: roll on side 1 full revolution for 30 seconds, tip on ends, repeat 3× total.

Pressure rinsing: 40 psi for 30 seconds. Rinsate may be stored or used in next batch.

Refillable container: return to dealer; never tamper. Nonrefillable: follow label for recycle/dispose; never reuse.

Ag Container Recycling Council: Recycling program for pesticide containers.

Rinsate reuse rules: same labeled site, doesn''t exceed label rate, compatible with new product, no strong cleaners.

Lightweight oil (1–5 gal): Added before final flush to coat sprayer interior for storage.

After cleanup: remove contaminated clothes and shower immediately, not at day''s end.

Chapter 10 — Planning the Pesticide Application