1. Pesticide Formulations
Stephen J. Toth, Jr. Wayne G. Buhler
Department of Entomology Department of Horticultural Science
North Carolina State University North Carolina State University
Photograph from U. S. Department of Agriculture

2. Pesticide Formulations
A pesticide formulation is a mixture of active and inert (inactive) ingredients
Some formulations are ready-to-use; others must be further diluted with water, a petroleum based solvent, or air before they are applied
Tim McCabe

3. Purpose of Formulations
Increase pesticide effectiveness in the field (availability to pests, persistence)
Improve safety features of pesticide (diminish the hazards to user or environment)
Enhance the handling qualities of pesticide (equipment, storage)
Tim McCabe

4. Considerations for Choosing a Pesticide Formulation
Do you have the necessary equipment to apply the formulation properly?
Can the formulation be applied safely in the area and under the conditions of application?
Will the formulation reach the target and stay in place long enough to control the pest?
Will the formulation harm the surface on which it is applied?

5. Types of Pesticide Formulations
Liquid Formulations Emulsifiable Concentrates Solutions Liquid Flowables Aerosols
Dry Formulations Dusts Baits Granules or Pellets Wettable Powders Soluble Powders Microencapsulated Dry Flowables
Fumigants
Adjuvants

6. Emulsifiable Concentrate (EC or E)
Contains a liquid active ingredient, solvent and agent to allow formulation to mix with water to form an emulsion
Product
Diluted
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7. Emulsifiable Concentrate (EC or E)
Used: in agriculture, ornamentals, turf and forestry, and for livestock, structural and public health pests
Advantages: easy to handle, transport and store; little agitation required; not abrasive; doesn’t clog nozzles; and leaves little residue on treated surfaces
Disadvantages: mixing and calibration required; toxic to plants and humans (easily absorbed through the skin); can deteriorate metal and rubber; and is flammable

8. Solution (S)
Contains an active ingredient dissolved in a liquid solvent (water or petroleum-based); either a concentrate (must be further diluted) or ready-to-use formulation
Product
Diluted
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9. Solution (S)
Used: for structural pests, livestock and poultry pests, space sprays, shade tree pests, and mosquito control
Advantages: no agitation needed
Disadvantages: a limited number of formulations of this type available
Dana Downey

10. Liquid Flowable (F or L)
Contains insoluble, finely-ground solid active ingredient mixed with a liquid (and inert ingredient) to form a suspension
Product
Diluted
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11. Liquid Flowable (F or L)
Used: same pest control operations as emulsifiable concentrates
Advantages: easy to handle and apply; seldom clogs nozzles
Disadvantages: require moderate agitation and may leave a viable residue on surfaces
Bill Tarpenning

12. Aerosol (A)
Contains one or more active ingredients and solvent (usually petroleum distillate); packaged in a ready-to-use pressurized container, or applied in a smoke or fog generator
Used: space spraying, crack and crevice treatments for structural and household pest control
Advantages: convenient; the user can purchase small quantities of pesticide; easily stored; and does not lose activity
Disadvantages: limited uses; difficult to confine to target site or pest; and risk of inhalation injury

13. Dust (D)
Ready-to-use dry formulation that contains a low percentage of the active ingredient plus a dry, inert carrier (talc, chalk, clay, ash, etc.); used dry
Used: to treat seed, control indoor pests (crack and crevice and spot treatments) and parasites on pets and livestock, and used for pests in home gardens
Advantages: usually ready-to-use, no mixing; requires simple equipment; effective in hard-to-reach areas
Disadvantages: drifts off-target; residues easily moved off target by air and water (rain); doesn’t stick as well as liquids; uneven distribution; irritates eyes, nose, throat

14. Bait (B)
Contains a small amount of dry active ingredient mixed with food or some other attractant; pests ingest pesticide
Product
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15. Bait (B)
Used: inside buildings for control of ants, roaches, flies, rodents; outdoors for control of rodents, other mammals, birds, slugs, snails and insects
Advantages: ready-to-use with no mixing; little hazard to applicator; even distribution not necessary; controls mobile pests; can be removed when pests not present
Disadvantages: can be attractive to children, pets and wildlife; pests may prefer crop to bait; dead pests may cause odor problem or secondary poisoning of wildlife

16. Granule (G) or Pellet (P)
Ready-to-use, dry formulations prepared by applying liquid active ingredient to coarse, absorptive material such as clay; pellets are larger, more uniform in shape
Used: granular formulations used for soil pests, larval mosquitoes, aquatic pests, and for aerial application to avoid drift; pellets used as pelleted seed, fumigants
Advantages: particles settle quickly (low drift); little hazard to applicator; simple application equipment (e.g., spreaders); slow release of pesticide
Disadvantages: do not stick to foliage or surfaces; may need to incorporate in soil; may require moisture to activate pesticide; non-target wildlife may use as feed

17. Wettable Powder (WP or W)
Dry, finely-ground formulation with active ingredient mixed with clay or talc; formulation mixed with water to form a suspension for application
Product
Diluted
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18. Wettable Powder (WP or W)
Used: widely used, commercial applications for most pest problems
Advantages: easy to store, transport and handle; less likely than EC formulation to harm plants, animals and surfaces; less skin and eye absorption than EC
Disadvantages: inhalation hazard to mixers; requires good agitation, will settle out of solution; abrasive to pumps and nozzles; leaves visible residues on surfaces

19. Soluble Powder (SP)
Similar to wettable powder, but dissolves readily and forms a true solution; few pesticides available in this formulation
Advantages: has all of the advantages of the wettable powders; non-abrasive to pumps and nozzles; constant agitation not required
Disadvantages: inhalation hazard during mixing

20. Microencapsulated Pesticide (M)
Particles of pesticide active ingredient (liquid or dry) surrounded in a plastic coating; formulated product mixed with water and applied as spray; following application the capsule slowly releases the pesticide
Advantages: increased safety to applicator; easy to mix, handle and apply; slow release of pesticide
Disadvantages: constant agitation required; bees may pick capsules and take back to their hive

21. Dry Flowable (DF)
Active ingredient is prepared as dry, granular-sized particles; granules mixed with water, where they break into fine particles and form a suspension for application
Product
Diluted
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22. Dry Flowable (DF)
Advantages: more easily measured and mixed than wettable powders; less inhalation hazard to mixers
Disadvantages: requires constant agitation to keep the formulation in solution

23. Fumigant (F)
Pesticides that form poisonous gases when applied; formulated as liquids or solids; can be released under pressure, high humidity or water vapor
Used: agriculture (soil, greenhouses, bins); structural pest control; regulatory pest control (ports, borders)
Advantages: toxic to wide range of pests; can penetrate very small areas; usually requires a single treatment
Disadvantages: highly toxic to humans and non-target organisms; requires use of specialized application equipment and protective equipment (respirator); the treatment area must be enclosed or covered

24. Adjuvant
Chemical (inert) added to a pesticide formulation or tank mix to increase the effectiveness or safety
Includes wetting agents, emulsifiers, spreaders, stickers, foaming agents, thickeners, safeners, compatibility agents, buffers, and anti-foaming agents
North Carolina Pesticide
Applicator Training Program

25. Reference
Applying Pesticides Correctly: A Guide for Private and Commercial Applicators. Unit 3: Formulations. pp