7.2 Dry Formulations, Baits, Fumigants, and Packets

Dry products are not safer because they are not liquid

Rule 40-21-3-.01 still expects you to match formulation hazards to the site. Dry products remove some splash-and-runoff drama and create inhalation, drift of fines, pump abrasion, and bait-nontarget problems instead. National Core Chapter 4 groups these as dry or solid formulations plus a short list of other formulations that are not simple liquids: microencapsulated materials, water-soluble packets, attractants, impregnates, and fumigants.

The same brand-name decoding you used on liquids applies here. A name in the Sevin 5G pattern means 5 percent active ingredient as granules. A 50WP is half active ingredient by weight as a wettable powder. Do not confuse the number in the name with how many pounds of product per acre. That number is concentration, not rate.

Dusts (D) and tracking powders

Dusts are ready-to-use mixtures of a low percentage of active ingredient—National Core still teaches a working range of about 0.5 to 10 percent—plus a finely ground dry carrier such as talc, clay, chalk, nut hulls, or volcanic ash. You do not mix them with water. You apply them with a duster to foliage, cracks, or seed.

Seed-treatment dusts are a Georgia Category 25 Seed Treatment topic. Treating cotton or peanut seed in a hopper or drum produces a cloud of fines at the operator’s breathing zone. Advantages: no water, simple equipment, coverage of hidden surfaces and seed coats. Disadvantages: easy drift, inhalation during loading and application, visible residue, poor rainfastness, and high wastage if wind exceeds the label’s comfort zone. Dusts are the wrong choice on a windy pivot road next to a school, and they are a poor substitute for a labeled liquid seed treatment when the label offers one with less airborne dust.

Tracking powders are specialized dusts used so that a rodent or crawling pest picks up particles on fur or tarsi and ingests them while grooming. They are not a broadcast lawn product. Using a tracking powder where children, pets, or sanitation workers can contact it is a classic misuse. Many tracking-powder labels tightly limit placement to wall voids and inaccessible runs. Category 35 industrial work may see them; Category 24 turf work should not treat them as fertilizer-spreader material.

Baits (B), including pastes and gels

A bait combines active ingredient with a food or other attractant. Block baits, pellets, meal, liquid baits (covered in 7.1), and pastes, gels, and injectable baits for cracks and crevices all belong to this family.

Advantages: you can place the dose where the pest feeds; you often use less active ingredient than a broadcast spray; gels reduce airborne residue in a kitchen or hospital (Category 35) compared with a fog.

Disadvantages the exam will not let you skip: children, pets, livestock, and wildlife will eat a bait that tastes like grain, peanut oil, or sugar. Secondary poisoning can follow when a dog eats a poisoned rodent. Nontarget birds pick up pellet baits that look like seed. If competing food is abundant in a pecan orchard or a poultry house, the pest may ignore the bait and you get a control failure that looks like resistance. Tamper-resistant stations, bait security, and the label’s indoor/outdoor placement rules are part of formulation competence, not a courtesy.

Granules (G) versus pellets (P or PS)

Granules are coarse, irregular particles. The active ingredient is coated on or absorbed into a dry carrier. They are ready to use. Typical uses: soil insects, preemergence weed control, aquatic sites (Category 26), and turf (Category 24)—including Georgia lawn-care, sod farm, and golf applications where a rotary spreader is already on the truck.

Advantages: low drift compared with dusts and fine sprays; reduced dermal exposure versus mixing an EC; particles fall through a turf canopy to the thatch or soil. Disadvantages: they need moisture to release many active ingredients, so a dry week after a granular turf insecticide can look like a product failure; particles do not coat foliage well; calibration of a spreader on a slope is easy to get wrong; some granules are attractive to birds; you cannot spray around a flower bed with the same precision as a directed nozzle.

Pellets are extruded so that size and shape are uniform. That uniformity makes spreader calibration more repeatable than with irregular granules. The hazards are otherwise similar. Because pellets often look even more like feed pellets or seed, wildlife and livestock pickup is a standard warning. Do not tell an exam item that pellets dissolve into a true solution in the spray tank—they are generally applied dry.

Fertilizer–pesticide combination granules are common on Georgia turf. Convenience is the advantage: one pass for nitrogen and a preemergence herbicide. The hazard is agronomic as well as legal: you may apply a pesticide when the pest is not present because the lawn needed fertilizer, locking you into a pesticide rate you cannot separate from the nutrient rate. If the pesticide is not labeled for that site or that turf species, the combination bag does not create a new use.

Wettable powders, soluble powders, and dry flowables

Wettable powders (WP or W) look like dust. They contain a high percentage of active ingredient—often 50 percent or more, with a National Core range of about 5 to 95 percent—plus dry inert carrier and wetting and dispersing agents. You mix them with water. They do not dissolve. They form a suspension that will settle in minutes without agitation.

WP advantages: relatively inexpensive; often less phytotoxic than ECs because they lack a heavy petroleum solvent load; less dermal absorption than ECs during handling of the dilute spray; excellent residual on porous surfaces because particles stay on the surface.

WP disadvantages you must be able to list: inhalation of concentrate dust during opening, measuring, and dumping; abrasion of pumps, nozzles, and screens; clogging of fine screens; visible residue on waxed floors, cars, and ornamental foliage; constant agitation in the tank and in the boom. A Category 21 cotton applicator who treats a WP like an EC will cut the life of a centrifugal pump and will lay down a streaky rate when agitation fails at the far end of the boom.

Soluble powders (SP)—sometimes coded WSP when the powder itself is water-soluble, not to be confused with water-soluble packets—dissolve into a true solution. Once dissolved they need little agitation and they do not abrade equipment the way WPs do. Relatively few agricultural actives are truly soluble. Measuring still raises dust, so mix/load inhalation remains a concern.

Water-dispersible granules (WDG) or dry flowables (DF) are WP chemistry in granule form. You still mix them with water; they still become a suspension of fine particles; they still need agitation. The gain is less mixing dust and easier measuring. The percentage of active ingredient can be very high, sometimes approaching 90 percent by weight. Cold water and weak agitation are why WDGs sometimes sit on the tank bottom as swollen lumps—an incompatibility look-alike that is really a mixing-procedure failure.

Microencapsulated materials and water-soluble packets

Microencapsulated formulations (often M, ME, or CS for capsule suspension) put droplets or particles of active ingredient inside a polymer shell. The tank mix is typically a suspension of capsules. Advantages: timed or extended residual, reduced volatility and odor, sometimes reduced handler exposure to the concentrated active, and compatibility with some tank partners that would chew up an EC. Disadvantages: agitation required; capsules can settle; some capsules are about the size of pollen, so foraging bees may carry them to the hive and create a delayed kill that a contact EC would have shown at the flower; cleanup of dried capsules in a tank is messy. A Georgia pecan or peach applicator (still Category 21) who sprays a microencapsulated insecticide during bloom without reading the bee statement is not using a safer formulation. The formulation changed the exposure pattern; it did not repeal the label.

Water-soluble packets (WSB or WSP—water-soluble bags or packets) enclose a premeasured wettable or soluble powder in a film that dissolves in the tank. You do not open the packet. Dry gloves matter: wet hands can start the film dissolving in your palm. Advantages: reduced mix/load inhalation and dermal contact with concentrate, accurate dose, less container rinsing of the inner product. Disadvantages: you cannot split a packet for a small ornamental tank unless the label allows a specific method; unused packets must stay dry; once the film dissolves, the spray is as hazardous as any other dilute mix of that active. Drop packets into water with agitation running and allow them to dissolve before you stack on ECs or adjuvants that can coat a half-dissolved bag.

Fumigants and stored-product work

Fumigants are pesticides that are gases, or that become gases, after release. They penetrate commodity masses, burrows, and structures that a spray cannot reach. There is usually little residual after aeration—control happens during the exposure period. Hazards are extreme: inhalation toxicity, lack of warning odor in some products unless an odorant is added, and the need for respiratory protection and clearance devices the label specifies.

Georgia Category 38 Agricultural Commodity Fumigation is the commercial category for fumigating stored grain, oilseeds, and similar agricultural commodities. That is not the Structural Pest Control Commission fumigation credential used for houses. Do not study the wrong exam. Phosphine-generating products, sulfuryl fluoride where labeled, and other commodity fumigants belong on the Category 38 side after you pass General Standards. A peanut buying point in southwest Georgia, a cottonseed store, or a grain bin in the Piedmont is a Category 38 site, not a place to just throw a canister in and shut the door under a plant-agriculture license that does not include 38.

Georgia scenarios

A Category 24 technician spreading a granular preemergence herbicide on a Marietta lawn is using low-drift particles that still need irrigation or rainfall to activate. Telling the homeowner it works dry contradicts both the formulation and many labels. If the bag is a fertilizer combination, the technician must still confirm the pesticide is labeled for that turf species and that the pest justifies a pesticide pass, not only a nitrogen pass.

A Category 25 seed conditioner dusting peanut seed should wear the PPE the dust label requires, including a respirator if listed, because the mixing hazard for dusts is inhalation, not splash.

A Category 38 applicator sealing a grain bin is not choosing between EC and WP. The formulation class is fumigant, the competency is Category 38, and General Standards still test whether you know that fumigants have little residual and high inhalation hazard.