12.2 Formulations, Adjuvants, Compatibility, and Persistence

Quick Answer: 40 CFR 171.103(c)(5)(ii) is types of formulations. (c)(5)(iii) is compatibility, synergism, persistence, and animal and plant toxicity. (c)(5)(iv) is hazards and residues. On the New Jersey Core, that cluster means: pick a formulation the label and the site can support, add an adjuvant only if the label allows it, jar-test tank mixes, and treat leftover activity as residue you must still control.

A formulation is the whole packaged product: active ingredient plus inerts, solvents, carriers, emulsifiers, and sometimes a synergist. Two products with the same active ingredient are not interchangeable if one is an emulsifiable concentrate (EC) and the other is a granule (G). The Core will test the letters because the letters change how you mix, what you wear, what you injure, and what you leave behind.

Common formulation codes

Dusts (D), pellets (P), microencapsulated (ME/CS), and ultra-low volume (ULV) concentrates also appear on New Jersey labels, especially in 8B mosquito and some 7A work. Microencapsulated products can leave a longer residual with a different dermal feel; they are not “safer than the label.” RTU is still a pesticide: N.J.A.C. 7:30-9.6(c) still forbids pouring it into a food or drink bottle “because it is already dilute.”

Why the letters change toxicity and phytotoxicity

40 CFR 171.103(c)(5)(iii) names animal and plant toxicity of the formulations, not only of the active ingredient. An EC solvent can burn foliage on a 3A ornamental that would have tolerated a WP or DF of the same active. The same EC can defat skin and move through gloves faster than a dry granule. WP dust is an inhalation formulation hazard at the bag even when the dilute spray is a low dermal risk. Granules cut spray drift and then create a new hazard: a child, a goose, or a dog on a treated 3B lawn. Baits shift the hazard toward secondary poisoning and non-target feeding, which is why New Jersey wrote 7:30-10.3 instead of hoping the formulation would take care of itself.

Fumigants are a formulation and a method. 40 CFR 171.103(c)(7)(ii) requires additional certification for fumigant use. A 7A aerosol is not a 7C fumigant. Sealing a structure and releasing a gas is a different formulation risk: inhalation, aeration, and equipment compatibility with hoses and tanks.

Choose formulation to match the site. A restaurant kitchen may need a crack-and-crevice RTU or bait, not an EC space spray. A windy right-of-way may need a granule or a coarse spray the label allows, not an aerosol. A greenhouse with sensitive blooms may forbid ECs that a field crop will tolerate.

Adjuvants only when the label allows

An adjuvant is a substance added to the tank to improve mixing, spreading, sticking, buffering, or drift control. Working types:

• Spreaders (surfactants, wetters) reduce surface tension so spray films a waxy leaf.
• Stickers help the deposit resist rain and wash-off.
• Drift retardants thicken or otherwise shift droplet size.
• Buffers and acidifiers adjust pH or hardness.
• Anti-foaming agents, compatibility agents, and crop oils / methylated seed oils.

The pesticide label is still the law. If the label says “do not add surfactants,” adding a spreader is use inconsistent with labeling — FIFRA and N.J.A.C. 7:30-10.2(a). If the label is silent, many products still allow adjuvants that do not themselves change the rate or the site, but you do not get to invent a tank mix that the label forbids, and you do not use an adjuvant to justify a higher rate or an unlabeled site. Some labels require a specified surfactant for the product to work; skipping a required adjuvant is also a label violation and an effectiveness failure under (c)(5)(v).

Adjuvants have their own labels. A drift retardant that is itself a pesticide or that changes droplet size into a range the pesticide label forbids is not a free extra. On New Jersey turf and ornamental routes, an extra sticker that leaves visible residue on a school playground or a patio is a hazard and residue problem under (c)(5)(iv) even if the herbicide rate was legal.

Compatibility, synergism, and the jar test

Compatibility means products can be mixed and applied together without physical or chemical failure.

Physical incompatibility is what you can see: heat, curds, sludge, oil layers, gel, or grit that clogs screens. Chemical incompatibility is what you may not see: one product inactivates another (alkaline hydrolysis of some insecticides in high-pH water; certain herbicides antagonizing glyphosate; mixing an oxidizer with an organophosphate). Synergism is a greater-than-additive effect. Some labels build in a synergist (PBO with pyrethrins). Tank-mix synergism you hope for, without a label statement, is not a legal theory — it is a compatibility and labeling gamble.

Never mix products whose labels prohibit tank mixing. Never mix with a fertilizer, a micronutrient, or a soap “because we always have.” If the label allows a tank mix or is silent and the combination stays inside each product’s directions, jar-test first.

A workable jar test

1. Put on the mix/load PPE each concentrate requires.
2. Use the same water you will spray — municipal hardness in Essex is not pond water in Cumberland.
3. Mix a small batch in a clean glass jar in the same order you will fill the tank. A common order when the labels do not specify one is W-A-L-E-S: wettable powders and dry flowables, agitation, liquids/flowables, emulsifiable concentrates, surfactants last. The pesticide labels win if they give an order.
4. Shake, then let the jar stand 10 to 15 minutes.
5. Fail signs: precipitate that will not resuspend, oil slick, rubbery curd, unexpected heat, or a color change the labels do not describe.
6. Pass: the mix resuspends with gentle shaking and stays usable.
7. Dispose of the test mix as a pesticide mixture on a labeled site at a labeled rate, or as the label and New Jersey disposal rules require. Do not dump it in a storm drain.

Incompatible mix in a 300-gallon turf tank is a N.J.A.C. 7:30-10.2(b) handling event: harm or a significant risk of harm, plus a ruined load you still have to store and record.

Persistence, residues, plant and animal toxicity

Persistence is how long the pesticide remains in the environment in a form that can still act. Sunlight (photodegradation), water (hydrolysis), microbes, temperature, soil binding, and the formulation all change persistence. A residual insecticide is persistent on purpose on a baseboard. A soil-applied herbicide that is still active when the next ornamental is planted is persistence you did not want.

Residue is what remains on or in the treated surface, crop, animal, or soil. 40 CFR 171.103(c)(5)(iv) pairs hazards and residues. The Core expects you to connect:

• Restricted-entry interval (REI) and PHI as residue clocks, not customer-service suggestions.
• Food-handling establishments: residues on food, utensils, or food-contact surfaces from the wrong formulation (an EC space spray versus a bait in a tamper-resistant station).
• Tracking of granules or wet residues onto untreated carpet, school desks, or a hive.
• Livestock, pets, and pollinators taking systemic residues in pollen, nectar, forage, or water.
• Persistent products moving with soil or leachate toward groundwater (Chapter 10 develops the hydrology; this chapter names persistence as a product characteristic you chose at the shop).

Short-lived botanicals and some soaps have little residual — useful around people, weak if the pest will reinvade the same night. Long-residual products cut callbacks and raise non-target and take-home risk. Microencapsulated and some bait formulations can persist where a child or a pet can still reach them; formulation persistence does not override 7:30-10.3 or child-access duties.

Plant toxicity of a formulation shows up as burn, spotting, or growth distortion on non-target ornamentals and turf. Animal toxicity of a formulation shows up as higher dermal or inhalation dose from solvents and dusts, and as secondary poisoning from baits. Those are formulation facts, not a reason to skip labeled PPE.

Worked New Jersey scenarios

Scenario F — EC on a 3A nursery. A Mercer County greenhouse uses an insecticide EC on blooming hanging baskets. The active ingredient is labeled, but the solvent burns petals. A labeled WP, DF, or RTU of a compatible product would have been the formulation match. Phytotoxicity here is a (c)(5)(iii) formulation problem, not “the plant was sick anyway.”

Scenario G — unlabeled drift retardant. A 3B label is silent on adjuvants except “do not use spray adjuvants.” The operator adds a drift retardant because the park is next to a parking lot. That addition is inconsistent with labeling.

Scenario H — skipped jar test. A 6B crew tank-mixes a WP herbicide with an EC insecticide in hard water. The tank fills with sludge, nozzles plug on Route 295, and mix spills during clearing. A 15-minute jar test would have shown the curd. The leftover sludge is still a pesticide mixture for records and disposal.

Scenario I — persistent bait left behind. A 7A contract ends. Accessible rodent bait stays in the ceiling. N.J.A.C. 7:30-10.3(d) requires the applicator or applicator business to remove all accessible bait after the application is completed or the contract is terminated. Persistence of the bait is not permission to abandon it.

High-yield traps

• Same active ingredient, different formulation: not interchangeable.
• EC = solvent phytotoxicity and equipment-seal risk; WP = dust and agitation; G = tracking and wildlife; RTU is still a pesticide.
• Adjuvants only if the pesticide label allows them; required adjuvants must be used.
• Jar test in the same water and same order; chemical incompatibility can be invisible.
• Residual control is also a residue hazard (REI, PHI, tracking, non-targets).
• Fumigants and rodent baits bring extra New Jersey and federal duties the formulation letters do not erase.

Official resources

• 40 CFR 171.103(c)(5) pesticide characteristics
• N.J.A.C. 7:30-10.2 pesticide use
• N.J.A.C. 7:30-10.3 rodent baiting
• N.J.A.C. 7:30-9.6 containers and container labeling