Page 6—Com Talk, Lancaster Farming, Saturday, April 17,1993
Adjuvants Enhance
Herbicide Performance
William S. Curran
Weed Specialist
Penn State
Adjuvants are commonly
used in agriculture to improve
the performance of pesticides.
Broadly defined, an adjuvant
“is an ingredient that aids or
modifies the action of the prin
cipal active ingredient.”
The use of adjuvants with
agricultural chemicals general
ly falls into two categories: for
mulation adjuvants (present in
the container when purchased
by the dealer or grower) and
spray adjuvants (added along
with the formulated product to
a carrier such as water).
The liquid that is sprayed
over the top of a crop, weeds, or
insect pest often will contain
both formulation and spray
adjuvants.
Formulation adjuvants are
added to the active ingredient
for a number of reasons, includ
ing better mixing and handling,
increased effectiveness and
safety, better distribution, and
drift reduction. These traits are
accomplished by altering the
solubility, volatility, specific
gravity, corrosiveness, shelf
President’s
Message
(Continued from Page 1)
your county agent about the 5
Acre Com Club yield contest.
You must be entered by July 1.
We hope to sec you at Ag Prog
ress Days in August, if not
before.
I think we are ready for the
challenges of 1993. The course
is somewhat familiar, though
some of the hurdles may sur
prise us. We can be sure of one
thing—the type of com grower
we will be tomorrow is being
forged by the melting pot of
experiences we face today.
Sincerely,
H. Grant Troop
PMCGA President
life, compatibility, or spreading
and penetration characteristics.
With the large number of for
mulation options available (sol
utions, emulsions, wettable
powders, flowables, granules,
encapsulated materials, etc.),
adjuvants become even more
important in assuring consis
tent performance.
Spray adjuvants are added to
the tank to improve pesticide
performance. Literally hun
dreds of chemical additives are
now available that fall into this
category. Spray additives can
broadly be grouped into two
categories: activator adjuvants
that include surfactants, wet
ting agents, stickers-spreaders,
and penetrants, and special pur
pose or utility modifiers such as
emulsifiers, dispersants, stabil
izing agents, coupling agents,
co-solvents, compatibility
agents, buffering agents, anti
foam agents, drift retardants,
nutritionals, etc.
Descriptions of the more
common types of special pur
pose adjuvants follow and
Table 1 lists some common
products sold for these
purposes.
Don't Let This
Happen To You
Again! Valuable
Harvest
Time is Lost
WAITING
On Others
. •
Table 1. Selected trade names and manufacturers of special
purpose adjuvants
Trade Name
Compatibility agents
Blendex
Combine
E-Z Mix
Mix-Aid
Spray-Aide
Latron AG44M
Unite
Drift reduction
38F
Lo-Drift
Nalco-Trol
Chem-Trol
Sta-Put
Target NL
Windfall
Anti-foaming agents
DeFoamer
D-Foamer
Foam Buster
The Unfoamer
Buffers
Buffer P.S.
Buffer Xtra Strength
Combine
Latron AG-44M
LI-700
Special Purpose
Adjuvants
Compatibility agents
Allows simultaneous applica-
«r»
TPMJK NIWO
Manufacturer
Helena
Riverside/Terra
Loveland Industries
Agway
Miller Chemical
Rohm and Haas
Loveland Industries
Loveland Industries
Rhone-Poulenc
Nalco Chemical
Loveland Industries
Nalco Chemical
Company
Agway
Riverside/Terra
Riverside/Terra
Agway
Helena
Loveland Industries
Helena
Helena
Riverside/Terra
Rohm and Haas
Loveland Industries
tion of two or more ingredients.
Most often used when herbi
cides are applied in liquid fertil
izer solutions. These are gener-
PENNSYLVANIA MASTER CORN GROWERS ASSOC., INC.
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1248 South Mountain Rd.
■ ■■■ Dlllsburg, PA 17019
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A3O-CO0)
ally organic phosphatic acid
esters that are anionic and form
emulsions resistant to strong
salt concentrations. Unless the
pesticide label states that it can
be mixed with liquid fertilizers,
a compatibility agent should be
included.
Buffering agents Buffers
usually contain a phosphate salt
which will maintain a slightly
acid pH when added to alkaline
waters. Citric acid has more
recently been promoted for this
purpose. These are added to
higher pH solutions to prevent
alkaline hydrolysis of some
organic phosphate and carba
mate insecticides.
Antifoam agents - Arc added
to suppress surface foam and
minimize air entrapment that
can cause pump and spray
problems. Defoamers are usu
ally silicones or siloxanes.
Drift reduction (thickeners)
These modify spray charac
teristics to reduce spray drift by
minimizing small droplet for
mation. Drift inhibitors are gen
erally polyacrylamide or poly
vinyl polymers.
Activator
Adjuvants
Activator adjuvants are by
far the most common type of
additives used to enhance her
bicide performance.
Although some products are
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