Pyroxasulfone: Profile of New Herbicide

Masanori Kobayashi*, Greg Rich,

Hisashi Honda and Takuro Shinohara,

K-I Chemical USA, White Plains, NY;

IntroductionO N S

Me

Me

N

N

CF3

F2HCO Me

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O

New Class of Chemistry

Mode of Action VLCFAE inhibitor

Group 15(WSSA)/K3(HRAC) Herbicide

Outstanding residual activity providing season long weed control

Flexible application timing

Excellent selectivity for many crops

Pyroxasulfone (ISO approved)

Code : KIH-485

Physical / Chemical ProfileChemical Name: Pyroxasulfone S-metolachlorDevelopment Code: KIH-485 CGA-77102CAS Number: 447399-55-5 87392-12-9Molecular weight: 391.3 283.8Appearance: white crystalline solid Yellow to brownish liquidOdor Slight characteristic odor Unspecific odorMelting point: 130.7 -61.1 Relative Density: 1.60 g/cm3 1.12 g/cm3

Octanol/Water Partition Coefficient:

log Pow 2.39 @ 25 log Pow 3.05 @ 20

Vapor pressure : 2.4 x 10-6 Pa @ 25 3.7 x 10-3 Pa @ 25Water Solubility: 3.49 mg/L Water@20 480 mg/L Water@25

Environmental Fate Adsorption/desorption in soil: KOC ads 57-114

KOC des 119-226

Terrestrial field dissipation: t1/2 soil 16-26 days (S-metolachlor: 11-30 days)

Aquatic field dissipation: t1/2 water 0.58-0.67 daysT1/2 sediment 2.5-3.2 days

Hydrolysis in pH 5, 7, 9 buffer: Hydrolytically stable during 15 days at pH 5,7 and 9

Photolysis on soil surface: t1/2 minimal degradation (<10%)

Toxicological ProfileSpecies Study Active ingredient Effect Level

Rat Acute oral LD50 > 2000 mg/kg bw

Rat Acute dermal LD50 > 2000 mg/kg bw

Rat Acute inhalation LC50@4 hours > 6.56mg/L

Bobwhite quail Acute oral LD50 LD50 > 2250 mg/kg bw

Bobwhite quail Reproduction study NOEC=1000 ppm a.i.

Mallard duck Short-term dietary LC50 LC50 > 5620 ppm a.i.

Mallard duck Reproduction study NOEC=60 ppm a.i.

Rainbow Trout(Oncorhynchus mykiss)

Fish, acute LC50(most sensitive species)

96 hr LC50 >2.2 mg/L

Daphnia (Daphnia magna) Daphnia, acute EC50 48 hr EC50>4.4 mg/L

Green Algae(Pseudokirchneriella subcapitata)

Alga, acute EC50(most sensitive)

96 hr EbC50= 0.00038 mg/L96 hr ErC50= 0.00079 mg/L

Honeybee(Apis mellifera) Haneybee, acute contact 48hr LD50 >100μga.i./bee

Target Site

Pyroxasulfone inhibits multiple elongation steps to produce 20, 22, 24, 26 and 28 chains fatty acid in VLCFA production system.

Cell Division Inhibitor

Mississippi Research Station Field Trial

0

20

40

60

80

100

SETVI AMAPA SETVI AMAPA SETVI AMAPA

92 DAA 57 DAA 31 DAA

Early Pre-plant Pre Early Post(Corn V2 Stage)

with Glyphosate

Per

cent

con

trol

Pyroxasulfone 250 s-metolachlor 2140 g a.i./ha

Weed Control at EPP, Pre and EPostin Corn field

0

20

40

60

80

100

2-4W 4-6W 6-8W 8-10W

after application

perc

ent

contr

ol

s-metolachlor 1787 pyroxasulfone 210 gai/ha

Common Waterhemp Control in Corn and Soybean field

2004-2008 University trial data

S-met n=14 10 5 2

pyro n=19 15 7 5

0

20

40

60

80

100

0-60 60-90 90-120 120-150 150-180 180-210 210-240

Days after application

perc

ent

contr

ol

Pyroxasulfone 50 75 100 gai/ha

Italian Ryegrass Control in Winter Wheat

n=4 2 2 3 7 5 2

2005-2009 University trial data

Pyroxasufone was applied in September and October

Soil: Silt loam

Registration Status of Pyroxasulfone

Corn registration was approved in Feb 2012.

Soybean registration is anticipated by the end of 2012.

Wheat and Cotton registration should be approved in 2013.

Pyroxasulfone 85 WGPyroxasulfone alone (Zidua® herbicide)

Recommended use rate

Corn

90-240 gai/ha (1.5oz - 4oz/A)

Fall, EPP, PPI, Pre and EPost (Up to V4 stage)

Soybeans

90-240 gai/ha (1.5oz - 4oz/A)

Fall, EPP, PPI, Pre and EPost (1st to 3rd trifoliate)

Spring and Winter wheat

42-150 gai/ha (0.7oz/A – 2.5oz/A)

EPP, Pre and EPost (4th tiller stage)

Pyroxasulfone + FlumioxazinPremixture Product with Flumioxazin (FierceTM herbicide)

Recommended use rate

Corn (No till and Minimum till)

90+70～135+105 gai/ha (3.0oz ～ 4.5oz/A)

PrePlant Barndown, EPP (30DBP to 7DBP)

Soybeans

90+70～135+105 gai/ha (3.0oz ～ 4.5oz/A)

PrePlant Barndown, EPP, Pre (within 3DAP)

Wheat (No till and Minimum till)

90+70 gai/ha (～3oz/A)

EPP(30 days must pass before planting)

Pyroxasulfone Products in USACommon Name Product

NameRegistration

Status Target Partner

Pyroxasulfone Zidua®

Registered Corn , Non crop/IVMBASF

Pending Soybean, Wheat, Cotton

Pyroxasulfone +Flumioxazin FierceTM

Registered Corn, Non crop/IVM

ValentPending Soybean, Wheat, Cotton

Pyroxasulfone +Fluthiacet-methyl AnthemTM Pending Corn

FMCPyroxasulfone

+Fluthiacet-methyl

+Atrazine

AnthemTM

ATZ Pending Corn

Crop Safety of PyroxasulfonePRE POST

ZEAMX cornGLXMA soybeanTRZSS (AS/AW) wheatGOSHI cottonARHHY peanutsHELAN sunflowerSOLTU potatoPIBSS pea, fieldIPOBA potato, sweetCUUMA squash, winterCORSA coriander, commonLYPES tomatoSORBI sorghumBEAVA sugarbeet

Bayer code Crop name Field trials

less than 20%20% to 30%more than 30%

Sweet Potato trial(2007, MS)

Mint trial(2009, OR)

Current Requested Minor Crops

PrePlant PostPlant Epost

0.106 0 0 0

0.213 0 5 0

0.426 0 3 5

PYR+FLU0.213+0.094

2 - -

Valor 0.094 5 - -

Dual II M 1.2 2 6 0

ChemicalRate

(lb ai/A) Crop Injury %

PYR

Trial 1 Trial 2 Trial 3

PYR 0.184 3 0 3

ETF 1 0 8 -

MCPB 0.5 - - 3

Pigweed Bindweed Fluvellin

PYR 0.184 100 72 80

ETF 1 88 75 -

MCPB 0.5 - - 33

ChemicalRate

(lb ai/A)

Weed Cntrol %

Crop Injury %Chemical

Rate(lb ai/A)

Application timing: PostEvaluation: June to July

Application timing: Pre Transplant, Post Transplant, EPostEvaluation: 28DAA

PYR: PyroxasulfoneETF: Ethofumesate

PYR: PyroxasulfoneFLU: Flumioxazin

Potential Minor Crops and Minor UseZidua® FierceTM

Sunflower AlfalfaField Pea SugarcaneSweet Potato Sweet PotatoOnion OnionMint MintGrass Seed Grass SeedTFNV TFNVCane crops (e.g.blackberry ) Stone FruitsBush berry crops (e.g. blueberry) Pome FruitsMelons GarlicVarious vegetables- row middle Various vegetables - row middle

Pyroxasulfone summary

A new herbicide, Pyroxasulfone has unique physical/chemical properties, a favorable environmental and toxicological profile.

The mode of action, VLCFA, works to control many current herbicide resistant weeds.

Pyroxasulfone provides consistent, season long weed control of grass and small seeded broadleaf weeds with flexible application timing.

It has good to excellent selectivity for many potential minor crops.

Thank you for your attention

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support