InhibitorInhibitors of carotenoid biosynthesis4-hydroxyphenol-pyruvate dioxygenase (HPPDs).
5 RELATED HERBICIDES:
Balance
Isoxaflutole 750 g/kg
Benzofenap 300
Benzofenap 300g/L
6 GENERAL DESCRIPTION:
A pre emergent or early post emergence, soil residual, root absorbed and translocated herbicide for the control of emerging broad leaved weeds in Chickpeas.
7 APPLICATION METHODS AND TIPS:
Apply to bare, even soil after planting and before crop emergence.
Weed control may be poor during dry periods but it usually reactivates when rain comes.
Direct contact with crop seed may cause damage.
Don't incorporate.
Ensure furrows are closed over the seed before spraying.
Don't use on soils with <10% clay or with a C.E.C less than 4.5 meq/100g.
Don't use on soils with <1% O.M unless the C.E.C is greater than 9.5 meq/100g.
Avoid use on freshly limed soils.
Best results when applied to bare soil and rain follows.
Adequate but reduced weed control can be expected for applications onto heavy stubbles.
If small weeds are present add 1% spray oil (or wetting agent). If larger weeds are present add a knockdown herbicide.
Apply within 24 hours of mixing. Product will settle in spray vat if left without agitation.
If possible apply before rainfall events (or during them, if no emerged weeds) rather than after.
A 25% yield reduction can be expected if used on furrow seeded crops. Harrrow to fillin furrows before spraying.
Pre sowing applications generally result in 10-15% yield loss compared to post sowing applications.
8 WEATHER:
Rainfast in hours.
Heavy rain after application may cause crop damage especially in light soils. Heavy rain after a dry period may cause transient crop yellowing and stunting.
Frost effects:
Wind:
Inversions:
Temperature:
Delta T and relative humidity: Avoid application when Delta T is greater than
Soil moisture at application: Best results when soil is moist. OK in dry soil but rain required for activation.
9 ADJUVANTS:
Don't use adjuvants when applying to sugar cane.
Wetting agents: Use non ionic wetting agents if very young weeds are present.
Spray oils: Use spray oils if very young weeds are present.
10 WATER QUALITY:
Hard water:
Salty water:
Colloids:
pH:
Tank life: 24 hours because it tends to settle in the tank.
11 COMPATIBILITY:
Trace elements.
See HerbiGuide Compatibilities button.
Compatible with Actril (2,4-D ester + ioxynil).
12 EQUIPMENT:
Normally applied by boom sprays with water as a carrier at 30-250 L/ha using flat fan nozzles at 150-400 kPa. Bayer recommend water volumes of 50-250 L/ha.
13 SPRAYER DECONTAMINATION:
Clean Up:
Remove filters and nozzles and manually clean separately. Rinse with soapy water or water plus wetting agent and run through boom. Rinse with water.
Decontamination:
Remove the nozzles and screens and clean separately and allow to soak in a mixture of 500 mL chlorine bleach (4%) per 10 L water for at least 30 minutes.
Rinse sprayer with soapy water (eg 500 mL or g of Drive, Dynamo, Omo or Surf per 100 L water) or water plus 0.25% wetting agent and run through boom. Drain tank and flush with clean water for a minimum of 10 minutes to remove all traces of liquid fertilisers or adjuvants containing ammonia, such as ammonium sulphate or ammonium nitrate, before adding chlorine bleach, because bleach and ammonia will react to release a toxic gas.
Fill tank with clean water and add 300 mL household chlorine (4%) bleach per 100 L water, flush through hoses and boom then stand for 15 minutes with agitation engaged, repeat. Rinse tank, hoses and boom thoroughly with clean water to remove traces of bleach.
Rinse filters and nozzles in water and replace.
14 HERBICIDE RESISTANCE:
15 REPLANTING INTERVALS:
Crop
Replanting interval
Rainfall required
Barley
10 weeks
100 mm
Canola
9 months
350 mm
Clover
21 months
500 mm
Cotton
7 months
350 mm
Faba Beans
9 months
250 mm
Field Peas
9 months
250 mm
Lentils
21 months
500 mm
Lucerne
9 months
350 mm
Maize
10 weeks
100 mm
Medic
21 months
500 mm
Mung beans
7 months
250 mm
Oat
10 weeks
100 mm
Sorghum
7 months
250 mm
Soybeans
7 months
250 mm
Sunflowers
7 months
250 mm
Wheat
10 weeks
100 mm
These may be longer on acid soils.
Cultivation before recropping will reduce the risk of damaging residues.
Residues rarely remain in the soil after 4 months in most agricultural situations where the soil has been moist and microbial activity has not been limited.
16 WITHHOLDING PERIODS:
Crop
Type
Time
Chickpea
Grazing
4 weeks.
Chickpea
Harvest
Not required
Sugarcane
Grazing
Don't graze treated crops
Sugarcane
Harvest
19 weeks.
17 RE-ENTRY PERIOD:
12 hours.
Wear protective clothing if in contact with the crop before the spray has dried.
18 PROTECTIVE CLOTHING:
Overalls, boots and washable hat. Use gloves and face shield when handling the concentrate.
19 SOIL:
May leach in sandy soils. Crop damage is more likely in sandy, gravelly, low organic matter and low clay soil types. Usually safe on soils with a clay content greater than 10%.
Do not apply to poorly drained soils, sodic soils or compacted soils as crop damage may occur.
Use is generally restricted to soils with organic matter contents greater than 1% and C.E.C. greater than 4.5 meq/100g. On soils with an organic matter content of less than 1% use is generally restricted to soils with a C.E.C. of more than 9.5 meg/100g.
20 MODE OF ACTION:
Inhibitor of carotenoid biosynthesis.
Uptake and translocation:
Isoxaflutole is absorbed mainly through the roots and seed but also through shoots as they grow through the soil. The active component, DKN is mainly taken up by the roots and is readily translocated in both the phloem and xylem to meristematic regions of roots and shoots where it inhibits carotenoid production. The uptake is passive and directly proportional to water uptake by the plant. In drought conditions weed control is poorer.
Physiological effects:
Isoxaflutole stops photosynthesis, the plant turns white as chlorophyll and pigments break down and it dies from lack of sugars.
Isoxaflutole is converted to DKN (diketonitrile) which is the herbicidally active molecule. This inhibits the HPPD (hydroxyphenyl pyruvate dioxygenase) enzyme which subsequently stops quinone production. Quinone is required for carotenoid pigment production. Carotenoids are plant pigments that protect the chlorophyll from being broken down by sunlight. This results in death of the chloroplasts which are the major site of photosynthesis. With no sugars being produced by photosynthesis the plant soon dies from lack of energy derived from sugars. Quinone is also needed in the electron transport system for deriving energy from photosynthesis.
Residual Life and Breakdown:
On dry soil isoxaflutole is stable. Rain and to a lesser extent microbes dissolve the product which rapidly converts to DKN with a half life of 1-3 days. DKN is absorbed by the plant and broken down by soil microbes with a half life of 8-30 days. The breakdown is faster at higher temperatures and higher pH.
Isoxaflutole and/or DKN is adsorbed by clay and organic matter. On soils with low clay contents, low organic matter levels or low cation exchange capacities (C.E.C.) the herbicide is more likely to leach and cause crop damage. Use is generally restricted to soils with organic matter contents greater than 1% and C.E.C. greater than 4.5 meq/100g. On soils with an organic matter content of less than 1% use is generally restricted to soils with a C.E.C. of more than 9.5 meg/100g.
Degradation is mainly by hydrolysis and microbial breakdown. It has potential to leach but in field studies residues remain in the surface horizons. After 4 months soil residues are rarely detected.
21 SELECTIVITY:
Affects broad leaved species mainly.
DKN is metabolised to inactive products more quickly in tolerant plants than susceptible plants.
Crop tolerance:
Post sowing pre emergence applications can cause crop damage at label rates in very light sandy or gravelly or low organic mater or low clay content soils. Heavy rain after application may result in crop damage especially in thes soils.
Crops on soils that have been recently limed may also be damaged.
Post emergence application to tolerant plants such as Chickpeas results in a large uptake of herbicide that may turn the crop yellow and cause a temporary cessation in growth.
Varietal sensitivities:
Yorker Chickpea is sensitive and post planting pre emergence applications and may result in yield loss.
Most Sugarcane varieties appear to be tolerant.
Effect on Clover Species:
Damages clover.
Effect on Medic Species:
Kills medics.
Effect on Lucerne:
Damages lucerne.
Effect on Native Plants:
22 DISEASE AND INSECT EFFECTS:
Crops with root systems that have been affected by insects or diseases are more prone to herbicide damage.
23 PLANT SYMPTOMS:
Susceptible plants turn white as chlorophyll is broken down by sunlight. Many plants may not emerge. Those that do emerge turn white and rarely produce more than 2 leaves before dying. Bleaching normally appears on the leaf edges and tips then spreads to the rest of the leaf.
Plants that that don't turn completely white will usually need to be controlled by other sprays.
SECONDARY EFFECTS:
24 TOXICITY:
Summary:
It is of low toxicity to the user and animals.
Will irritate eyes and skin.
Possible risk of harm to the unborn child.
Very toxic to aquatic organisms.
Details:
Poison schedule: S5
Mammalian toxicity: Low
Acute oral LD50: >5000 mg/kg (rats), [For comparison table salt is 3000 mg/kg]. Harmful if swallowed.
Acute dermal LD50: >2000 mg/kg (rabbit).
Skin: Slight irritant (rabbit). Will irritate skin.
Skin sensitisation: Non sensitising (guinea pig - Buehler test)
Eye: Slight to moderate irritant (rabbit). Will irritate eyes.
Vapour inhalation: LC50 - >5.26 mg/L air (rat). Harmful if inhaled.
Chronic oral toxicity NOEL: ppm for two years.
Not mutagenic or neuro-toxic.
At very high doses liver tumours have been observed in rats and mice and thyroid tumours in rats. Negligable increased risk of cancer is expected for humans. It has possible developmental toxic effects and is a category 3 substance with a R63 risk phrase of "Possible risk of harm to the unborn child."
Crystaline silica (sand) in the formulation can cause lung damage and is classified as carcinogenic.
Fish: Toxic LC50 >1.7 mg/L for 96 hours for rainbow trout for isoxaflutole. LC50 >65 mg/L for 96 hour for rainbow trout for Balance 750 WG.
Invertebrates: Toxic. EC50 >1.5 mg/L for Daphnia magna for 48 hours for isoxaflutole. EC50 >5 mg/L for Daphnia magna for 48 hours for Balance 750 WG.
Bees: low toxicity.
Arthropods: toxicity.
Earthworms: low toxicity.
Algae: Very toxic. EC50 = 0.12 mg/L (120 hour). IC50 = 0.33 mg/L (72 hour) for isoxaflutole. IC50 = 10.5 mg/L (72 hour) for Balance 750 WG.
Duckweed: Very toxic - 0.003 mg/L (14 day)
Eastern Oyster and Mysid shrimp are the only species tested so far to show sensitivity.
25 TOXICITY SYMPTOMS:
26 FIRST AID:
If SWALLOWED: Wash out mouth with water. Do not induce vomiting. Do NOT give anything by mouth to a semiconscious or unconscious patient. Seek medical advice.
If on SKIN: Wash with soap and water, remove contaminated clothing.
If in EYES: Wash out with water. See a doctor if irritation persists.
If INHALED: Remove patient to fresh air. If breathing has stopped apply artificial respiration and seek medical aid.
Advice to doctor: Treat symptomatically.
Contact the Poisons Information Centre on 131126.
27 ENVIRONMENTAL FATE:
Half life in soil: Isoxaflutole has a half life in moist soil of 1-3 days. In dry soil it is stable and non volatile so it will last a long time. The herbicidally active breakdown product HKN has a half life in the soil of 8-30 days.
Half life in water: days at pH5 and 35 C.
It has an EPA classification for soil mobility that ranges from
Ground water contamination
Accumulation in milk and tissues.
pH stability:
Photolysis rate: Very slow. Stable in sunlight.
Hydrolysis half life:
Biodegradation rate:
Leaching potential - Mobile in some soil types (eg sands with <10% clay).
28 REGISTERED CROPS:
Chickpeas and sugarcane.
See HerbiGuide Species Solution tab.
29 REGISTERED WEEDS:
See HerbiGuide Species Solution tab.
30 REGULATION AND LEGAL:
UN number: NA.
CAS numbers: Isoxaflutole 141112-29-0. Kaolin 1332-58-7. Silica, quartz 14808-60-7.
Hazchem code: Not applicable.
NOHSC classification: Hazardous. Possible risk of harm to the unborn child.
Land transport:
Dangerous goods class: Not classed as a dangerous good for transport by road or rail.
Sea transport:
Proper shipping name: ENVIRONMENTALLY HAZARDOUS SUBSTANCE, SOLID, N.O.S. (isoxaflutole mixture), Class 9, UN 3077, Packing group III. Marine Pollutant, Class "P".
Class: 9.
Packaging group: III.
EPG: Not applicable.
31 PROPERTIES:
Colour: grey granule with no odour.
Odour: None.
Form: Solid granule.
Empirical formula:
Water solubility: at 25 C, Isoxaflutole - 6.2 ppm. Practically insoluble, disperses in water; DKN - 326 ppm.
Oil solubility:
Octanol:Water ratio at 25 C: LogPow Isoxaflutole = 2.19 to 2.32. LogPow DKN = 0.4.
Soil organic carbon absorption coefficient (Koc):
Vapour Pressure: at 25 C. 1 X 10-6 Pa (for isoxaflutole).
Dissociation constant: pKa
Melting point: 140 C (for active ingredient).
Boiling point: C.
Molecular weight:
Bulk density: 1.44 g/mL to 0.7 kg/m3 quoted.
Specific gravity:
pH: 4-6 in 1% solution in water.
Flammability: Combustible. Under severe dust conditions it may form an explosive mixture with air.
Flashpoint: C.
Autoignition: C.
Reactivity - May give off toxic substances such as oxides of carbon and nitrogen and hydrofluoric acid if burnt.
Corrosivity: Non corrosive.
Shelf Life: Several years.
(When Stored under Ideal Conditions)
32 SPILLS:
Extinguish possible sources of ignition.
Avoid creating dust. Dampen spill if necessary. Prevent spilled material from entering water courses. Wipe floors with a damp cloth.
33 FIRE:
Extinguish with water spray, foam, carbon dioxide or dry agent.
Toxic fumes may be released in fire. Wear breathing apparatus or avoid smoke.
34 COMMENTS:
35 REFERENCES:
Aventis Technical Manual 2001.
Bayer (2006) Balance 750 WG Label 49456-606
Bayer (2005) Balance 750 WG MSDS December 15, 2005.
Acknowledgments:
Collated by HerbiGuide. For more information see www.herbiguide.com.au or phone 08 98444064.