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Strengthening Organic
Enforcement Rules
PHOTO BY KINDEL MEDIA
Prepared for USDA TOPP by Acres U.S.A.
www.acresusa.com | 1
How Can Herbicides Be Used in
Organic Farming Systems?
THEY’RE NOT FOR EVERYTHING — BUT THERE IS A ROLE FOR ECOLOGICALLY
SAFE ORGANIC AND NATURAL HERBICIDES
By Steve Diver, Farm Superintendent, University of Kentucky Research Farm
I
t is a truth universally
acknowledged
cal herbicides.
all
To that end, many companies are
In this article we’ll discuss the
farmers — even those
starting to produce a group of her-
regulations associated with the
who aren’t involved in ecological,
bicides known as organic herbicides.
use of specific herbicides on organic
organic, sustainable or regenera-
These are sometimes also known as
farms, types of organic herbicides
tive agriculture — have an interest
natural herbicides, green-chemistry
and best-use practices, and holistic
in reducing their toxic load and in
herbicides, least-toxic herbicides,
methods for weed control in organ-
finding ways to reduce or eliminate
alternative herbicides or non-chemi-
ic systems.
2 | Copyright Acres U.S.A.
that
synthetic pesticides.
REGULATING HERBICIDES
ON CERTIFIED ORGANIC FARMS
Before examining different types
and uses of organic and natural herbicides, it’s important to understand
how these products fit into USDA’s
organic program standards.
Section 205.205 of the USDA National Organic Program is the crop
rotation practice standard. It talks
ic Materials Review Institute (OMRI),
about using different crop rotations
the Washington State Department of
and cover crops to provide for pest
Agriculture, or the California Depart-
control in annual and perennial
ment of Food and Agriculture.
TYPES OF ORGANIC AND
NATURAL HERBICIDES
What are organic and natural herbicides made of? One of the original nat-
crops. Section 205.206 talks about
But there is another way to be
ural herbicides was simply straight 20
how weed problems may be con-
able to use a product, and that is
percent acetic acid. Since then, some
trolled, and it mentions several prac-
through a manufacturer’s statement
manufacturers started blending in
tices that all organic farmers know:
of organic compliance. The problem
other substances, such as essential
mulching with fully biodegradable
is that this can turn into a very slow
oils, and so you’ll have products like
materials; mowing; livestock graz-
review and approval process by
acetic acid and citric acid. There are
ing; hand weeding and mechanical
your accredited certifying agency.
several products that are ammonium
cultivation; flame, heat, or electrical
But there are some companies that
nanoates, and then some products
means; or plastic or other synthetic
make good products who just don’t
that are blends of different essential
mulches. Then, section E says, “When
want to go through OMRI or the oth-
oils, like clove and cinnamon oil. A
the practices above are insufficient
er two agencies.
new generation of natural herbicides
to control weeds, a biological or a
botanical substance, or a substance
included on the national list of allowed synthetic substances, may be
applied to control weeds, provided
that these are all documented in the
Organic System Plan.”
Section 205.601 discusses allowed
synthetic substances. For herbicides, for example, that includes
soap-based
products.
However,
these are restricted for non-cropland areas — for farmstead maintenance, like roadways, ditches, rightof-ways, building parameters, etc.
So, how can an organic farmer
know whether a substance they want
to use for weed control is allowable?
One way is to look for one of the
RESOURCES FOR RESEARCHING ORGANIC HERBICIDES
NOSB Technical Evaluation Reports (ams.usda.gov). When the Organic
Foods Production Act started in 1995, they wanted to develop an indepth examination of products. Over the years it has commissioned
hundreds of these reviews, or technical evaluation report.
Many natural and organic herbicides have been thoroughly analyzed.
The reports are roughly a dozen to 20 pages long, including detailed
assessment of what the product consists of, how is it used, how it fits
into the organic program, whether there alternatives to it, etc. Based
on these reports, the product is voted upon by the NOSB board. It’s
either approved or prohibited.
Cornell University’s program on integrated pest management (ecommons.cornell.edu). Cornell’s program looks at active ingredients that
are eligible for minimum-risk pesticide use. For example, they have
assessed essential oils, seed oils, organic acids, protein meals, surfactants, etc.
three big logos: those of the Organwww.acresusa.com | 3
utilizes caprylic and capric acid. Yet
acid to enhance the effect.
another group includes ammoniated
salt of fatty acids.
These types of natural and organ-
BEST PRACTICES FOR ORGANIC
AND NATURAL HERBICIDES
ic herbicides are all non-selective
The products listed above are se-
The active ingredients of these
herbicides with a burnback effect.
lective burnback, contact herbicides.
products can be categorized into a
They’re contact herbicides. They do
They do not have a systemic effect.
few different groups:
not function as systemics. They have
They cannot be used, for example,
•
Acetic acids
a real use on the farm, but they do
to effectively kill an entire field of a
•
Organic acids
have some limitations.
cover crop. Also be aware that larger
•
Soaps
•
•
This list is not strictly certified or-
weeds will likely need repeat applica-
Essential oils
ganic. Some of these are approved
tion — especially grassy weeds, which
Botanicals
for use in organic production. Some
have belowground growth points.
Some of these products contain
are geared to home gardeners and
Secondly, the primary use of these
100 percent active ingredients, and
ornamentals. Some have prohibit-
products is for non-cropland areas
some have only a small percent-
ed ingredients. What’s important is
that tend to get weedy. If you want
age of active ingredient. Many are
that you study the label, look at the
to keep the farm tidy — for your
blends of different active ingre-
ingredients, check with your certify-
own sake, or because you have peo-
dients — for example, acetic acid
ing agency, and look for the OMRI,
ple visiting the farm for agritourism,
mixed with some kind of organic
WSDA or CDFA label.
these products can be very effective
Active Ingredients
Product Name
Acetic acid (vinegar)
Finalsan, Green Gobbler, Vinagreen
Acetic acid + citric acid
AllDown
Ammonium nanoate
AXXE, Final San-O, Mirimichi Green
Ammonium salt of fatty acid
Finalsan
Caprylic & capric acids
Suppress EC, Fireworxx, Homeplate
Citrus oil (d-limonene)
Avenger
Citric acid + clove oil
Burnout
Clove oil + soap
Herbor-G, Torched
Clove oil + lactic acid, potassium oleate, vinegar
Phydura
Clove oil + cinnamon oil
Weed Zap
Clove leaf oil
Matran EC
Eugenol (clove oil) + sodium lauryl sulfate
EcoSmart
Lemongrass oil + clove oil + soybean oil
Weed-A-Way
Pelargonic acid
Scythe
Potassium salt of fatty acids
Safer Weed & Grass Killer
Sea salt + vinegar
Harris Sea Salt 10X
Sodium chloride
A.D.I.O.S.
Soybean oil
EcoBlend
4 | Copyright Acres U.S.A.
Weed Terminator 20 + Organic Boost — a natural herbicide based on acetic acid mixed with emulsifiers — can be effective in burning down weeds around
the farm in non-cropland areas
www.acresusa.com | 5
Weed Terminator 20 + Organic
Boost used on weeds in gravel
Suppress EC, used next to
a lay-flat hose.
6 | Copyright Acres U.S.A.
This is a sequence
that shows how we
integrated an organic
herbicide (Suppress
EC — made with
caprylic and capric
acids) with other
cultivation practices.
This is a summer
squash field planted
into plastic mulch,
with plenty of hairy
galinsoga growing in
the aisles of the eightfoot rows, which
are set up so we can
drive a small tractor
through.
Notice the little bare
strip right next to the
plastic mulch. We
sprayed the edge of
the plastic mulch one
time with the organic
herbicide. There’s a
nice effect where it’s
been cleaned up right
next to the plastic
mulch — a place we
couldn’t get to with
the cultivator. Then,
just a few days later,
we cultivated the
aisle — you can see
this on the left —
with a small Kubota
and a Perfecta-style
cultivator with tines
and a rolling basket.
We were able to
achieve a nice
cleanup of the weeds
in the aisle with just
one application of the
organic herbicide next
to the plastic, plus
a single cultivation
pass.
www.acresusa.com | 7
for cleaning up these areas. The
but rather through a holistic system
photos and captions on the next few
that includes crop rotation, cover
But we also have a basket weed-
pages present some examples of
crops, living mulches and of course
ers for between the rows and a fin-
how natural and organic herbicides
different types of cultivation.
ger weeder for in-row weeds. These
can be most effective.
On our farm, we’ve developed a
stale seed-bedder that both shapes
HOLISTIC WEED CONTROL
ON ORGANIC FARMS
beds and does very shallow tillage
ever emerge on the bed.
are very effective for either direct
seeded or transplanted crops.
The other tool we use is weed-sup-
— less than one inch — to knock
pressive
As effective as organic and natu-
off the flushes of weeds. After the
warm-season crops, we’ll plant teff
ral herbicides can be for paths, field
first pass, we put in subsurface drip
between rows. Teff is a tiny seed
edges and around farm buildings,
irrigation, wait a week, and then
— there are 1.3 million seeds per
the fundamental way that a work-
run the stale seed-bedder through
pound. To suppress weeds, we use a
ing organic vegetable farm controls
again. In this way we can knock out
seeding rate that is triple the recom-
weeds is not via organic herbicides
95 percent of the weeds that will
mended rate for establishing forag-
8 | Copyright Acres U.S.A.
living
mulches.
For
es. For teff, then, since the suggested
a holistic system of cultural practic-
mind that these types of products
rate for forage is 12 pounds per acre,
es that includes crop rotation, using
are not designed to control all weeds
we’ll put on 36 with a turf spread-
cover crops, using living mulches,
on a farm by themselves.
er, and we get very effective weed
and having specialized equipment
control. Zero weeding is involved in
and weed barriers.
these alleyways after you get these
Organic and natural herbicides
nice living-mulch cover crops es-
can be important tools as part of this
tablished. We manage it with a flail
holistic weed control system, partic-
mower, mowing about twice during
ularly in non-cropland areas. They
the crop cycle, and then it winter kills.
can produce very effective burnback;
cle is supported through the United States Depart-
with modern formulations you’ll see
ment of Agriculture (USDA) Transition to Organic
CONCLUSION
immediate results, although some-
Fundamentally, we control weeds
times you’ll have to come back and
on working organic farms through
do a repeat application. Just keep in
This article was produced by Steve Diver of the University of Kentucky Research Farm, in coordination
with Acres U.S.A. and the Organic Crop Improvement Association (OCIA) International. OCIA is the
TOPP administrator for the Plains Region. This arti-
Partnership Program (TOPP). TOPP is a program of
the USDA Organic Transition Initiative and is administered by the USDA Agricultural Marketing Service
(AMS) National Organic Program (NOP).
www.acresusa.com | 9