Armezon Herbicide Technical Information Brochure - BASF

Armezon™ Herbicide Technical Information BrochureTough on Weeds. Safe on Corn.

1 Introduction

2 Physical and Chemical Properties

3 Mode of Action

4 Formulation and Use

5 Resistance Management

6 Weeds Controlled by Armezon™ Herbicide

8 Toxicological and Environmental Profile

10 Safety, Stewardship and First Aid Measures

cont

ents

A R M E Z O N H E R B I C I D E T E C H N I C A L I N F O R M AT I O N B R O C H U R E 1

above:

Armezon-sensitive weeds turn

white, called “bleaching” due

to loss of pigmentation.

Introduction

Developed by BASF, Armezon™ herbicide is a highly flexible

postemergence solution for corn growers, providing excellent control

of tough broadleaf weeds and grasses to help protect yield potential.

This broad-spectrum herbicide has a wide postemergence application

window and ultra-low use rate for improved operational efficiency.

Topramezone, the active ingredient in Armezon, is a pyrazolone, a unique subclass

of the HPPD-inhibiting herbicides. Armezon’s unique chemistry offers highly effective,

consistent control of key broadleaf weeds and grasses, including those that have

developed resistance to glyphosate, triazines, PPO- and ALS-inhibitors.

Field trials have demonstrated that Armezon offers excellent selectivity to all types of

corn, even specialty corn varieties that are sensitive to other herbicides.

Key Features and Benefits:

n Broad-spectrum foliar control of annual grasses and broadleaf weeds

n Safe for use on all field and speciality corn regardless of trait, even sensitive varieties

of popcorn, seed corn and sweet corn

n Wide postemergence application window to give growers application flexibility

n HPPD site of action offers an additional tool for weed resistance management

n Low active ingredient use rates for convenient handling and low

environmental exposure

n Excellent compatibility with other herbicides (e.g., dimethenamid-p, pendimethalin,

dicamba or triazines)

phys

ical

and

che

mic

al p

rope

rtie

sCode name BAS 670H

Active ingredient Topramezone

Chemical family Pyrazolone

Chemical name (IUPAC) (3-(4,5-dihydro-isoxazol-3-yl)-4-methanesulfonyl-2-

methylphenyl)-(5-hydroxyl-1-methyl-1H-pyrazol-

4-yl methanone)

Molecular formula C16H17N3O5S

Molecular mass 363.39

Melting point 220.9-222.2°C; 99.8%

Appearance White crystalline solid; 99.8%

Vapor pressure <1x10E-12; 20°C; 99.7%

<1x10E-12; 25°C; 99.7%

Solubility in water 510 mg/L at 20°C (pH 3.1); 99.7%

Solubility in Dichloromethane 25-29 g/L; DMF 114-133 g/L; acetone

organic solvents <10 g/L; acetonitrile <10 g/L; ethylacetate <10 g/L; toluene

<10 g/L; methanol <10 g/L; 2-propanol <10 g/L;

n-heptane <10 g/L; 1-octanol <10 g/L

All at 20°C; 99.9%

Partition coefficient - 0.81 pH 4 at 20°C; 99.9%

(log Pow) - 1.52 pH 7 at 20°C; 99.9%

- 2.34 pH 9 at 20°C; 99.9%

Solo formulation

A.I. content and 336 g ae/liter (2.8 lbs ae/gal)

formulation type SC (suspension concentrate)

2 A R M E Z O N H E R B I C I D E T E C H N I C A L I N F O R M AT I O N B R O C H U R E


Field Corn

Armezon Herbicide Metabolism-Based Selectivity

Time after treatment (hours)24

49% 51%

14%

86%

48

Ra

dio

ac

tivi

ty (

% o

f to

tal)

Black Nightshade

Topramezone

Inactive metabolites

Giant Foxtail


7%

48

21%


76%86%

48

24%14%

93%

79%

Ra

dio

ac

tivi

ty (

% o

f to

tal)

Ra

dio

ac

tivi

ty (

% o

f to

tal)

above:

Orange bars show very rapid

metabolism of topramezone

in corn varieties compared to

sensitive weeds. BASF lab

study 2004.

Mode of Action

Armezon™ herbicide is a potent inhibitor of HPPD (4-hydroxyphenylpyruvate dioxygenase,

an enzyme in the plastoquinone biosynthetic pathway), and indirectly the carotenoid

biosynthetic pathway. As a result, oxidative degradation of chlorophyll occurs, leading

to pronounced whitening or “bleaching” of sensitive weeds. These bleaching effects will

be visible on new growth within five days of treatment. Ultimately, growth is inhibited.

Under the influence of light, chlorotic tissues become necrotic, and sensitive plants usually

die within 7-14 days after treatment.

Selectivity

Because corn rapidly metabolizes Armezon to non-active substances, the herbicide

has excellent selectivity in field corn (grain, silage and seed), sweet corn, and popcorn,

regardless of trait and variety. Corn tolerance to Armezon is also based on a lower

sensitivity of the enzymatic target. In vitro assays show that Armezon exhibits a 10-fold

higher inhibitory activity of the HPPD enzyme in giant foxtail (Seteria faberi) than in corn.

Crop response (transient bleaching) from postemergence applications may occur under

extremely wet and/or cold weather conditions or when the crop is suffering from stress.

These effects are temporary. The plant quickly outgrows these effects and develops

normally with no affect on yield potential.


Absorption and Translocation

Armezon™ herbicide is translocated systemically throughout the plant. When Armezon

is used postemergence, susceptible weeds take up the herbicide through the treated

foliage and cease growth soon after application. Adjuvants enhance leaf absorption and

distribution of Armezon.

Formulation and Use

Armezon is formulated as a suspension concentrate (2.8 lbs ae/gal).

Application

Armezon can be used postemergence in a total post or sequential preemergence/

postemergence system. It will typically be tank mixed with atrazine and/or glyphosate

for a broader spectrum of postemergence weed control. Mixtures with a residual

herbicide such as dimethenamid-p or pendimethalin are recommended for early

postemergence applications.

Optimum postemergence activity of Armezon requires the addition of adjuvants such

as crop oil concentrate (COC) or methylated seed oil (MSO) plus ammonium sulfate (AMS)

or urea ammonium nitrate (UAN). For best performance use MSO except in cases where a

specific tank-mix partner prohibits use.

Young and actively growing weeds are more susceptible to Armezon applications

compared to weeds in advanced growth stages. Foliar uptake of Armezon may be

slowed down when used under cold and/or dry weather conditions, which may reduce

the speed and overall level of control.

Compatibility with Other Herbicides Armezon is compatible with other herbicides either as a tank mixture or as part of a

sequential weed management program.

Armezon is compatible with all classes of insecticides either as a tank mixture or as

part of a sequential program.

Tank mixtures with strobilurin-based fungicides may result in temporary crop response

(chlorosis, whitening, and/or necrosis). Subsequent growth is typically unaffected.

Refer to individual product labels for precautionary statements, restrictions, rates and

approved uses.

above:

Leaf uptake and translocation

of Armezon at 48 hours after

treatment in black nightshade

(Solanum nigrum) and giant

foxtail (Setaria faberi). Blue color

demonstrates translocation

outside treated leaf. BASF lab

study 2004.

T R E AT E DL E A F

T R E AT E DL E A F


Mixing Order

Mix Armezon™ herbicide thoroughly in container before dispensing.

Liquid fertilizer as a carrier for postemergence applications of Armezon is not

recommended. Use only water as a carrier.

n Water - Fill the spray tank 1/2 to 3/4 full with clean water and start agitation.

n Armezon - Add required amount to spray tank while agitating.

n After the Armezon has visibly dispersed, add spray additives and fill the remainder of

the tank with water.

Tank Mix Preparation

When tank mixing Armezon with recommended herbicides, add the other herbicides and

other components in the following order while agitating:

n Water - Fill the spray tank 1/2 to 3/4 full with clean water.

n Soluble packet products - Mix thoroughly.

n Water-dispersible products (such as suspension concentrates [SC; Armezon],

suspo-emulsions, wettable powders [WP], dispersible granules [DG], dry flowables

[DF], or liquid flowable [LF] formulations) - Mix thoroughly.

n Emulsifiable concentrate (EC) products

n Spray adjuvants

n Water - While agitating, fill the remainder of the tank with water.

Minimum Time From Application to Planting of Following Crops Application rates and timing can affect subsequent crops. Refer to country specific

product labeling for details.

Resistance Management

Resistance to HPPD inhibitor herbicides are known to exist. Always use good resistance

management practices including, but not limited to, tank mixtures and/or rotation

with herbicides that have a different site of action, crop rotation, and mechanical weed

control. Repeated applications of a single site of action in a weed management program

increase the probability of selecting for naturally occurring biotypes with less susceptibility

or tolerance.

As an HPPD inhibitor, Armezon herbicide is effective against broadleaf weeds and grasses

that have developed resistance to herbicides such as glyphosate, triazines, PPO- and

ALS-inhibitors.

above top:

Glyphosate + NIS + AMS

above bottom:

Armezon (0.75 fl oz/A) +

atrazine (1 pt/A) + glyphosate

+ COC + AMS

2011 University of Tennessee Field Trial – 8 Days After Treatment Confirmed glyphosate-resistant Palmer amaranth (Amaranthus palmeri)


Weeds Controlled by Armezon™ Herbicide

Postemergence applications of Armezon in the US have demonstrated control or

suppression of the following annual grasses and broadleaf weeds:

above:

Armezon herbicide provides

excellent control of tough

broadleaf weeds and grasses.

Scientific Name Bayer Code Common Name

Grasses

Brachiaria platyphylla BRAPP Broadleaf signalgrass

Digitaria spp. DIGSS Crabgrass spp.

Echinochloa crus-galli ECHCG Barnyardgrass

Eleusine indica ELEIN Goosegrass

Eriochloa villosa ERBVI Woolly cupgrass

Panicum dichotomiflorum PANDI Fall panicum

Panicum miliaceum PANMI Wild proso millet

Pennisetum glaucum PESGL Yellow foxtail

Setaria spp. SETSS Foxtail spp.

Sorghum bicolor SORVU Shattercane

Sorghum halepense SORHA Johnsongrass


Scientific Name Bayer Code Common Name

Broadleaf Weeds

Abutilon theophrasti ABUTH Velvetleaf

Amaranthus palmeri AMAPA Palmer amaranth

Amaranthus spp. AMASS Pigweed spp., Waterhemp spp.

Ambrosia spp. AMBSS Ragweed spp.

Anoda cristata ANVCR Spurred anoda

Brassica spp. BRASS Mustard spp.

Capsella bursa-pastoris CAPBP Shepherd’s-purse

Cassia tora CASTO Sicklepod

Conyza canadensis ERICA Horseweed (marestail)

Chenopodium album CHEAL Common lambsquarters

Datura stramonium DATST Jimsonweed

Galinsoga ciliata GASCI Hairy galinsoga

Helianthus annuus HELAN Common sunflower

Hibiscus trionum HIBTR Venice mallow

Kochia scoparia KCHSC Kochia

Lamium amplexicaule LAMAM Henbit

Latuca serriola LACSE Prickly lettuce

Polygonum spp. POLSS Smartweed

Richardia scabra RCHSC Florida pusley

Salsola iberica SASKR Russian thistle

Sicyos angulatus SIYAN Burcucumber

Sida spinosa SIDSP Prickly sida

Sinapis arvensis SINAR Wild mustard

Solanum spp. SOLSS Nightshade spp.

Stellaria media STEME Common chickweed

Xanthium strumarium XANST Common cocklebur

above:

Armezon™ herbicide

controls annual grasses and

broadleaf weeds including

Amaranthus spp.


Toxicological and Environmental Profile

Topramezone, the active ingredient in Armezon™ herbicide, does not demonstrate

genotoxic, carcinogenic or neurotoxic potential and has no effect on fertility. Some

evidence of developmental toxicity was observed in animal studies but only at doses that

are significantly higher than those used for risk assessments.

The residues present in corn are below the determination limit of 0.01 mg/kg grain or

silage, and do not raise a concern to consumers.

The ecotoxicity profile of topramezone is favorable and does not raise a concern to

the environment.

Mammilian Toxicology

Species Study Effect Level

Rat Oral LD50 > 2,000 mg/kg bw

Rat Acute dermal LD50 > 2,000 mg/kg bw

Rat Acute inhalation LC50 = > 5 mg/L

Rabbit Skin irritation Not irritating

Rabbit Eye irritation Not irritating

Guinea pig Skin sensitization Not sensitizing (maxim test)

Ames test Mutagenicity Negative

Toxicity to Avian Species


Bobwhite quail C. virginianus

Birds, acute oral LD50 > 2,000 mg a.s./kgbw NOEL > 2,000 mg a.s./kgbw

Toxicity to Freshwater and Estuarine Organisms


Rainbow trout Orcorhynchus mykiss

Fish, acute Static, 96h LC50 > 100 mg/L

Bluegill L. macrochirus

Fish, acute Static, 96h LC50 > 250 mg/L

Rainbow trout Orcorhynchus mykiss

Fish, early life stage Flow-through 96d NOEC = 3.2 mg/L

Daphnia Daphnia magna

Water flea, acute Static, 96h LC50 > 100 mg/L

Daphnia Daphnia magna

Water flea, acute Reproduction, semi-static, 21d NOEC = 50 mg/L

Green algae Pseudokirchneriella subcapitata

Algae Static, 96h EbC50 =17.2 mg/L


Toxicity to Earthworms


Earthworm Eisenia foetida

Earthworm, acute LC50 > 1,000 mg/kg (dry soil weight)

Earthworm Eisenia foetida

Earthworm, acute NOEC = 2.96.3 mg/kg

Toxicity to Honeybees


Honeybee Apis mellifera

Acute oral

LD50 > 72.05 µg/bee

Honeybee Apis mellifera

Acute contact

LD50 > 100.00 µg/bee

Effect on Natural Resources

Soil: Neither topramezone nor its metabolites are stable in an active soil environment.

Water: Applied according to the label recommendation, topramezone and its metabolites

are degradable in natural water bodies and are within the regulatory thresholds.

Air: Volatilization studies from plant and soil surfaces showed a very low potential for

topramezone to be displaced into the atmosphere.

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Safety, Stewardship and First Aid Measures

Hazards to Humans and Domestic Animals

Caution: Causes moderate eye irritation. Avoid contact with skin, eyes, or clothing.

Harmful if swallowed or absorbed through the skin. Wash thoroughly with soap and water

after handling.

Personal Protective Equipment (PPE)

Some materials that are chemically resistant to this product are listed below. If you want

more options, follow the instructions for Category A on an EPA chemical resistance

category selection chart.

Applicators and other handlers must wear:

n Long-sleeved shirt and long pants

n Chemical resistant gloves Category A

n Shoes plus socks

Discard clothing and other absorbent materials that have been drenched or heavily

contaminated with this product’s concentrate. DO NOT reuse them. Follow manufacturer’s

instructions for cleaning and maintaining PPE. If no such instructions for washables exist,

use detergent and hot water. Keep and wash PPE separately from other laundry.

User Safety Recommendations

Users should:

n Wash hands before eating, drinking, chewing gum, using tobacco, or using the toilet.

n Remove clothing/PPE immediately if pesticide gets inside. Then wash thoroughly and

put on clean clothing.

n Remove PPE immediately after handling this product. Wash the outside of gloves

before removing. As soon as possible, wash thoroughly and change into clean clothing.

Storage Notes

For topramezone, the shelf-life study in original containers confirmed excellent storage

stability for 24 months.

Topramezone is non-explosive and neither the active ingredient nor the co-formulants have

any oxidizing potential.

A R M E Z O N H E R B I C I D E T E C H N I C A L I N F O R M AT I O N B R O C H U R E 1 1

Cleaning Spray Equipment

To avoid injury to sensitive crops, drain and clean application equipment thoroughly using a

strong detergent or commercial sprayer cleaner according to the manufacturer’s directions.

Triple rinse the equipment before and after applying this product.

First Aid

If in eyes:

n Hold eyes open and rinse slowly and gently with water for 15 to 20 minutes.

n Remove contact lenses, if present, after first 5 minutes; then continue rinsing eyes.

n Call a poison control center or doctor for treatment advice.

If swallowed:

n Call a poison control center or doctor immediately for treatment advice.

n Sip a glass of water if able to swallow.

n DO NOT induce vomiting unless told to do so by a poison control center or doctor.

n DO NOT give anything by mouth to an unconscious person.

If on skin or clothing:

n Take off contaminated clothing.

n Rinse skin immediately with plenty of water for 15 to 20 minutes.

n Call a poison control center or doctor for treatment advice.

Hotline Number

Have the product container or label with you when calling a poison control center or doctor

or going for treatment. You may also contact BASF Corporation for emergency medical

treatment information: 1-800-832-HELP (4357).

1 2 A R M E Z O N H E R B I C I D E T E C H N I C A L I N F O R M AT I O N B R O C H U R E

BASF Agricultural Products 26 Davis Drive Research Triangle Park, NC 27709 USA +1 919-547-2000 www.agro.basf.com

Armezon is a trademark of BASF. © 2011 BASF Corporation All Rights Reserved. APN-12-23-A-DEW-002 December 2011

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Armezon Herbicide Technical Information Brochure - BASF