Insecticides can exist in three forms Pure form synthesized by the scientists 99 pure Technical form commercial manufactured in bulk by a basic manufacturer Formulation ID: 928977
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Slide1
INSECTICIDES FORMULATIONS
Slide2Insecticides
can exist in three forms
:
Pure
form
(
synthesized by the
scientists, 99% pure)
Technical
form
(commercial
) {
manufactured in bulk by a basic
manufacturer}
Formulation
(
add various
additives)
.
Slide3The
pure form
is synthesized by the scientists in laboratories, in small quantities (generally in grams)
with purity of 99%
or above.
The
technical insecticide
refers to a toxicant manufactured in bulk by a basic manufacturer.
After an insecticide has been commercially manufactured,
formulators
(other than the basic manufacturers) add various additives like powders, solvents, wetting agents, stickers, granules, synergists etc and prepare
formulations
like dusts, sprays, wettable powders, flowable,
emulsifiable
concentrates, granules, baits and encapsulated pesticides.
Slide4Slide5Slide6Slide7Slide8What is a Pesticide Formulation?
A pesticide formulation is a
mixture of chemicals
(
active ingredient
and inert, inactive,
substances) which
effectively controls a pest.
Some active ingredients do not dissolve in water or oil.
Others
can only be manufactured as solids.
Still
others are liquids or gases in their original forms.
Slide9Thus
formulating
a pesticide
involves:
mixing
the active ingredient
with
other materials
like:
solvents
, wetting agents, stickers, powders, or granules to improve its storage, handling, safety, application, or effectiveness.
Slide10Thus
pesticide formulation
consists of
two components
:
(1)
Active ingredient
(2)
Inert (inactive)
ingredients
.
Slide11Active ingredient(s)
Active ingredient is the
main chemical or toxicant
that produced the toxicity and actually control the pest.
Any active ingredient can often be available in more than one formulation, e.g.
diazinon
which is available as a
liquid
emulsifiable
concentrate
(4E)
, a
wettable powder
(50WP)
, or
a granule (14G)
.
Different companies may market the same active ingredient in different formulations.
Such
different formulations may have different characteristics, including human toxicity and amount (rate) that can be used.
Slide12Inert (inactive) ingredients
Inert ingredients are the
Additives
which are primarily
solvents
and
carriers
that help in delivery of the active ingredients to the target pest and enhance the utility of the product.
These Additives or inert ingredients include:
Adjuvants
and
Compatibility agents etc.
Slide13(A) Spray
Adjuvants
The spray
adjuvants
are added to pesticides to enhance the performance or handling.
Actually
adjuvant is a broad term and includes
Surfactants
(Surface-Active Agent),
Antifoaming agents
etc
.
The
Surfactants
are chemicals that modify the surface properties of materials to which they contact. Among the agricultural preparation three major types of surfactant are
Emulsifiers, Wetting agents
,
Stickers
and
Spreader
.
Emulsifiers
promote the suspension of liquid in another. They are most commonly used to disperse oil in water.
Slide14Wetting agents
reduced the interfacial tensions between normally repelling substances. Normally non-ionic
surfactants are used as wetting agents due to their compatibility with most pesticides and low toxicity to plants and animals.
Stickers
adhere the pesticide to the plant foliage and also to resist wash-off.
Spreader
that provide better spray coverage and adhesion. These are more commonly used with fungicides and insecticides.
Antifoam agents (foam suppressants)
.
That suppresses the foam formation when pesticides are agitated in the spray tank.
Slide15(B) Compatibility agents
which are used to reduce incompatibility (lack of mixing) of pesticides or pesticide and liquid fertilizer mixtures.
Thus the combination of an active ingredient with a compatible inert ingredient is referred to as a
formulation
.
Pesticides are rarely applied in their technical form. Therefore they are usually formulated for various purposes.
Slide16Purpose of formulating a Pesticide
(1) Ease of application
.
In Formulation a small quantity of toxicant to be mixed with a larger quantity of additive/carrier so that the pesticide can be applied more uniformly to a large area.
(2) Improved pesticide performance
.
Formulating a pesticide aids in application, aids in mixing, improves coverage and aids in uptake.
(3) Stability of product
.
Formulating a pesticide provides better stability in shipping and a longer shelf life.
(4) Safety
.
Formulating a pesticide that dilutes the active ingredient and its acute toxic effect so that the user is exposed to lower concentrations.
(5) Compatibility
.
Formulating a pesticide aids mixing with carriers.
Slide17Types of Formulations
Insecticide formulations are of three types:
Solid
Liquid
Gaseous.
Slide18Solid formulations
Dusts (D).
Granular (G).
Insecticide-fertilizer mixture:
Wettable powder (W or WP).
Soluble powders (SP)
(6) Water dispersible granules (WG or WDG).
Slide19(1) Dusts (D).
Dusts
are a very finely ground mixture of the active ingredient combined with
talc
,
clay
,
powdered nut hulls
, or other such materials.
They are used dry; never mix them with water.
The finished product may contain 0.1 – 25%
toxicant
and rest
carrier
.
Slide20Particle sizes of dusts ranges between
1
to
40 µ
.
In general, the
toxicity increases
as the particle size
decreases
.
For better results and to avoid drifts these formulations are applied in the early hours of the morning when the foliage is still wet with dew (just to retain the powder) and there is no wind to produce a drift.
Slide21(2) Granular (G).
Granules
are dry particles, having larger (
0.25 – 2.4 mm
) particle size than dust and are made up of porous materials, such as
corn cobs
or
walnut shells
, to which the active ingredient has been applied.
The percentage of active ingredient is lower than in an EC but usually higher than that of a dust formulation.
Slide22These formulations normally contain
2 – 10%
toxicant impregnated on absorptive material and are applied with some special applicators.
The granular formulations are ideally designed as soil insecticides, as gravity helps pull the granules to the soil surface where they can be mechanically incorporated or watered in.
Slide23(3) Insecticide-fertilizer mixture:
Granular insecticides are added to fertilizers to produce an insecticide-fertilizer mixture.
Such formulation is applied at regular fertilization time to provide nutrition to plants as well as to control the soil insects
.
Slide24(4) Wettable powder (W or WP):
Wettable powders
are dry powdered pesticide formulations.
They look like dusts but, unlike dusts, they contain
wetting and dispersing agents
so that they can mixed with water at the time of application.
They are usually more concentrated than dusts, containing
15 to 95%
active ingredient
.
Slide25The active ingredient
does not dissolve in water
and do not form a true solution so, thorough mixing is required in the spray tank to keep the formulation in suspension.
Some active ingredients which cannot be formulated into
ECs
can be formulated into
WPs
.
Good wettable powder formulations spray well and do not clog nozzles, but they are abrasive to pumps and nozzles. Most WPs are less likely than ECs to damage sensitive plants.
Slide26(5) Soluble powders (SP):
Like wettable powders they are also dry formulations, but when added to water they dissolve completely and form solutions.
Agitation is required only to get them to dissolve but once in solution, agitation is not needed.
The percentage of active ingredient is usually high compared to ECs and WPs.
Not many SP formulations are available.
Slide27(6) Water dispersible granules (WG or WDG):
This formulation appears as small pellets or granules.
It is easier and safer to handle and mix than wettable powders.
When the granules are mixed with spray water, they break apart and, with agitation, the active ingredient becomes distributed throughout the spray mixture
.
Slide28Liquid formulations/Sprays
(1) Undiluted pesticide liquid:
(2)
Emulsifiable
concentrate (E or EC).
(3) Flowable liquids (F or L).
Solutions concentrates (S) or
water
soluble concentrates:
Suspension concentrate (SC)
.
Encapsulated pesticides.
Slide29(1) Undiluted pesticide liquid:
Such formulations are used directly i.e. undiluted in
ultra-low-volume (ULV) quantities,
thus termed as
High concentrate liquids
or Spray concentrates or Ultra low volume (ULV) concentrates
.
They usually
contain a high amount
or high concentration of the
active ingredient
.
Most are made to be mixed with water or oil.
Slide30On the other hand there are formulations which
contain low amounts of the active ingredient, they are termed as
Low concentrate liquids or oil solutions (S)
.
They are made to be used as purchased, with no further dilution.This type of formulation is often sold for use in controlling household pests, like Hit, All out, Baygon
etc.
Slide31(2)
Emulsifiable
concentrate (E or EC).
Emulsifiable
concentrates
are liquid formulations in which the
active ingredient has been dissolved in oil
or other organic solvents and an emulsifier has been added.
Such formulations are designed to be mixed with water at the time of application and the resulting mixture is an emulsion.
Slide32In emulsion the two liquids do not effectively mix, but one is suspended as tiny droplets within the other.
The spray mixture must be constantly agitated otherwise the pesticide will separate from the water.
ECs, along with wettable powders (WP) are the most widely used formulations. ECs are easy to handle and require little agitation.
Slide33(3) Flowable liquids (F or L).
Such formulation consist of active ingredients that do not dissolve well in water or oil.
Thus the active ingredient is very finely ground and suspended in a liquid along with suspending agents, adjuvants, and other ingredients.
Such formulation can then be mixed with water and applied.
Slide34Flowables do not clog spray nozzles, require moderate agitation, and in many ways are as easy to handle as EC formulations.
Such formulations are available in liquid forms but some dry form are also available which are termed as dry
flowables
.
Slide35(4) Solutions concentrates (S) or water soluble concentrates
These
are liquids in their original state and are completely soluble in water or other organic solvents.
Properly prepared solutions do not leave unsightly residues and will not clog spray equipment.
But some can damage crops, so you may have to use another formulation.
Slide36(5) Suspension concentrate (SC)
.
These formulations contain finely divided solid particles in a liquid carrier similar to a flowable formulation.
Such formulations are designed to be mixed with water at the time of application.
Slide37(6) Encapsulated
pesticides
.
Encapsulated
pesticides are a fairly new type of
formulation.
The
active ingredient is contained in an extremely small
capsule.
The
capsules are suspended in a
liquid.
Slide38This formulation is mixed with water and applied with conventional sprayers.
It is relatively easy and safe to use, but can be a significant hazard for bees because the bees may take the capsules back to the hive with pollen.
Slide39Gaseous formulations
(1) Fumigants
(2) Aerosols
(3)
Pressure-liquefied gases.
Slide40(1) Fumigants
:
Most of the fumigants are inflammable therefore; they are mixed with some non-inflammable gas like carbon tetrachloride (CCl
4
).
Such formulations are useful in enclosed areas like houses, godowns, greenhouses, storage bins etc.
Slide41(2) Aerosols
:
Minute particles suspended in air (like mist or fog) are called aerosols.
Some formulations can be converted into aerosols of minute (0.1 - 50µ) particles by
burning the insecticide
,
vaporizing it by heating
,
atomizing mechanically
or by releasing the insecticide
dissolved in a liquefied gas
through a hole in the container.
Slide42Aerosols
are sold mainly for garden and home use, not for agricultural use.
They contain one or more pesticides in the same formulation in a can under pressure.
Usually the percentage of active ingredients is very low.
Their main advantage is that they are convenient to use.
Slide43(3)
Pressure-liquefied gases.
Some active ingredients are gases that kill when absorbed or inhaled.
They are often stored under pressure.
Under pressure, the gas may turn to liquid.These formulations may be injected into the soil, released under tarps (cover, sheet, oil cloth) or released into a grain storage elevator.
Slide44Some liquid formulations not stored under pressure turn to gases or vapors after they have been applied to the soil or crop.
If the formulation is an insecticide, the vapors of the active ingredient often do most of the killing of the pest.
If it is a herbicide, the liquid has to be incorporated into the soil before it turns to a gas; otherwise it will be lost to the atmosphere
.
Slide45Phosphine
, one of the most common fumigants for stored grain, is inserted as a solid capsule into the grain, where it vaporizes.
Fumigants pose a serious safety risk because they are highly toxic and easily inhaled.
They can also burn the skin.
Slide46Beside the above said formulations there are other formulations like:
(1) Poisonous baits
(2) Invert emulsions
Slide47(1) Poisonous baits
They contain
foods or other substances along with some attractant mixed with a pesticide and when be eaten by pests cause their death.
They are used to control mice, rats, and other rodents and animals.
Baits are also used to control ants, flies, or other insects, including some soil pests.
Bait formulations can be used in whole areas or for spot treatment, indoors and out. The percentage of active ingredient is low compared to ECs and other formulations.
Slide48(2) Invert emulsions
Which
contain a
water-soluble pesticide
dispersed in an oil carrier.
They require a special kind of emulsifier that allows the pesticide to be mixed with a large volume of oil, usually a fuel oil.
Slide49When applied, invert emulsions form large droplets which do not drift easily.
Invert emulsions are most often used along rights-of-way where there is a problem of pesticide drift on non-target plants.
Slide50How to Choose a Formulation
A
single pesticide
is often sold in
different formulations
. These formulations of the
same active ingredient
often behave differently.
For example, some types of formulation may mix in water better, while others may increase the chance of crop injury. Choose the formulation that is suitable for the job. Things to consider include:
Percent of active ingredient.
Ease in handling and mixing.
Slide51Personal safety risk.
Type of environment (agriculture, forest, urban, etc.).
Effectiveness against the pest.
Habits of the pest.
The crop to be protected.
Type of application machinery.
Cost.
Slide52