Formulations
A formulation is an agrichemical preparation supplied by the manufacturer. The formulation includes all contents inside the container—the active ingredient (that controls the target pest, disease or weed) plus inert ingredients (such as solvents, diluents, and various adjuvants).
Formulations serve one or more purposes:
- Ease of application, as they allow a small quantity to be mixed with a larger quantity of carrier so that the pesticide can be applied more uniformly to a large area.
- Improved pesticide performance through better application, mixing, coverage and uptake.
- Stability of product due to better stability in shipping and a longer shelf life.
- Safety as formulating dilutes the active ingredient and its acute toxic effect, resulting in the user being exposed to lower concentrations.
- Compatibility as formulating an agrichemical aids mixing with carriers.
There are two main groups of formulations:
1. Dry
- wettable powders
- water soluble powders
- water dispersable granules
- granules
| Formulation |
Description |
Advantages |
Disadvantages |
Wettable powders
(WP) |
Finely ground solids consisting of a dry carrier (a finely ground hydrophilic clay), pesticide, and dispersing agents
Does not dissolve but is suspended in the tank |
Low phytotoxity, low absorption through the skin of the applicator |
Form an unstable suspension when mixed with water, and require continuous vigorous agitation. Without agitation, a solid precipitate forms at the bottom of the tank
Must be made into a slurry before they are added to a spray tank
More wear on equipment and nozzles
Leave visible residues |
Water soluble powders
(WSP or SP) |
Finely divided solids that dissolve completely in water, forming true solutions when mixed with water |
Low phytotoxicity
Low absorption through the skin of the applicator
Will not separate or settle out upon standing and require no agitation once initially mixed. |
Require agitation for mixing |
Water dispersible liquids
(WDL, L, F, AS) |
Are finely ground solids suspended in a liquid system, forming a suspension when added to water in spray tank.
Consist of particles smaller than a WP, with an agitation requirement intermediate between that for WP and EC |
|
Cause nozzle wear intermediate between WP and EC, more similar to WP
Tend to settle out in storage; container must be vigorously shaken before use. |
Water dispersible granules (dry flowables)
(WG Flowable or WDG or DF) |
Are dry formulations of granular dimensions.
Contain granules made up of finely divided solids (a size similar to that in flowables) that combine with suspending and dispersing agents |
Similar to wettable powder but are easier to handle and mix |
Must have high agitation
More wear on equipment
Leave visible residues |
Granule
(GR, G) |
Consist of dry material in which small, dry carrier particles of uniform size are impregnated with the active ingredient. The carrier can be clay, sand, vermiculite, or corn cob. |
Applied with granular applicators
No mixing
No dust
No drift |
In general, they are more difficult to apply uniformly than a sprayed material. May be moved from applied area by wind or rain (for example, a banded application can be blown or washed off the top of the bed)
In general, require slightly more rainfall for activation than a sprayable formulation. On the other hand, rate of pesticide loss by volatilization is somewhat slower. |
2. Liquid
- suspension concentrate
- soluble concentrate
- emulsifiable concentrate
| Formulation |
Description |
Advantages |
Disadvantages |
Suspension concentrate
(SC) |
Form true solutions when mixed with water |
Smaller particles than WP
Require less agitation
Non abrasive. |
Settlement in storage and spray tanks |
Soluble (aqueous) concentrate
(SL) |
Form true solutions when mixed with water |
Easy to mix in the tank
Will not separate or settle out upon standing and requires no agitation once initially mixed. |
Some water conditions can cause precipitation |
Emulsifiable concentrate
(EC) |
Active ingredient dissolved in organic solvent, which forms an emulsion when mixed with water. |
Low abrasion and wear on equipment
Can be more effective than dry formulations
No visual deposits |
More likely to be phytotoxic, especially with mixtures
Solvents can enhance penetration into human skin
Require mild agitation to keep properly mixed in spray tank |