Lecture 12: Herbicide Formulations

What is a formulation?

A combination of Active and inert ingredients

Active Ingredient?

Pure technical grade chemical that does the killing

Inert ingredients

• No pesticidal characteristics

• Dilute

• Carrier

Name some Dilutantas and carriers

Organic solvent

• Mineral clay

• Surfactant

• Stabilizers

• Dyes

• Chemicals to enhance activity

What are the 3 mixtures of pesticides?

Solution, Suspension, and emusification

A Solution-

A mixture of one or more substances in another

substance (usually a liquid) in which all the ingredients are

completely dissolved. An example is sugar in water

A Suspension

- A pesticide mixture consisting of fine particles

dispersed or floating in a liquid, usually water or oil.

Examples include wettable powders or flowables in water

An emulsion-

A mixture of two liquids that are not soluble in

each other. One is suspended as very small droplets in the

other with the aid of an emulsifying agent. An example is

emulsifiable concentrate in water.

Why do we formulate pesticides?

1. poor activity unless formulated

2. needs to be diluted/concentrated

3. can improve safetey (microencapsulation, grannular vs powder)

What are the 2 purchase types for herbicides?

1. Ready to use (not worth buying)

2. Concentrates

What are the 2 formulation types for application?

1. granular/powders

2. sprayable formulations

Water soluble liquids

S

• SC

• WSC

Characteristics of water soluable

Form True solutions

• Typically transparent

• Not abrasive on equipmen

Advantages

Readily mix with water

• Equipment easy to clean

• Non-abrasive

• Typically non-volatile

• No agitation needed

• Doesn’t clog strainers

Water Soluble Powders

SP

• WSP

Characteristics of Water Soluble Powders

Water Soluble ai’s

• Form true solutions (like sugar/salt)

Advantages

• Form true solutions

• Doesn’t separate

• Non-abrasive to equipment

• Can be premeasured (WSB)

Disadvantages

• Inhalation hazards

• Have to keep dry

• Has to be weighed

Emulsifiable Concentrates

• E

• EC

Characteristics of Emulsifiable Concentrates

For non-water-soluble ai’s

• Usually milky-colored when mixed with water

• Emulsion (Oil in water emulsion)

• More commonly used easily mix in water

• Invert emulsion (water in oil emulsion)

• Very thick like mayo

• Special equipment needed

Liquid Flowables

• F

• AF

• L

Characteristics of Liquid Flowable

Finely ground solid suspended in

a liquid

• Agitation necessary

• Form suspension in water

Advantages

• Easy to handle

• Minor clogging issues

• Less likely to splash than other

formulations

Disadvantages

• Must be shaken

• Containers hard to rinse

• Visible residue on surface

• Moderate agitation

Water Dispersable Granuales

• Designated as

• DG

• WDG

• DF

• Basically a WP where the WP is

now a granule

Characteristics of Water Dispersible Granules

Advantages

• Less dusty than SP or WSP

• Easier to remove from the container

Disadvantages

• Same as SP and WSP

• Toomers Oaks got murked by these

Microencapsulated formulations

ME

Characteristics of Microencapsulation

Can be dry or liquid formulations

• Pesticide surrounded by polymer coating

Advantages

• Coatings help protect applicator

• Easy to mix, handle and apply

• Timed release herbicide = greater

efficacy long-term

• Reduced volatility

Disadvantages

• Constant agitation necessary

• Long REI and PHI

Advantages/Disadvantages of EC

Advantages

• Non-Abrasive to equipment

• Doesn’t clog screens

• No residue on surfaces

Disadvantages

• Easy to over/under-does (Concentrated)

• Solvents can be phytotoxic

• Easily absorbed into skin

• Solvents hard on rubber components

• Flammable and corrosive

Granules

G

Characteristics of granulars

Ai is impregnated on carrier particles

• Granule size is usually <10mm 3

• Applied dry as is. No dilution needed

• Common in turf and Ornamental

• Low % of ai’s for better distribution (1-15%)

A/D of granular

Advantages

• Ready to Use

• Drift hazard is low

• No settling

• Simple application and inexpensive equipment

• Slower release of ai

Disadvantages

• Application equipment needs frequent calibration

• Measured in wt. instead of volume

• May need to be incorporated

• Moisture needed for release of ai

• Can be toxic to animals thinking it’s “grit”

Pellets

• P

• Ai impregnated on a carrier particle (Clay)

• Granule size >10mm 3

• Similar to G formulations only larger size particles

• Usually in non-cropland use

How do producers utilize fertilizer?

Pesticide can be sprayed on fertilizer to do a dual control.