Cheetah is a selective and translocated post emergence herbicide that is absorbed mainly through leaves with some through the roots. The combination of a fop and dim group herbicide provides more effective control of ryegrass and the fenoxaprop improves Wild Oat control. The addition of a crop safener reduces the deleterious effects of sethoxydim on cereals. Its main use is for controlling Annual Ryegrass, Wild Oats and some other grasses in wheat, barley broadleaved crops and pastures. Toxicity to mammals and birds is low but it is toxic to fish. In land environments it presents few environmental hazards because of its low mobility in soil, low volatility, low toxicity and reasonably quick degradation in soil and water. Direct application to aquatic ecosystems should be avoided. Application to flood irrigated areas or similar may lead to contamination of water. Plants are likely to become resistant after repeated applications.
7 APPLICATION METHODS AND TIPS:
Best results when applied to young actively growing weeds in fine conditions.
Cheetah is normally applied in water with wetting agent as a post-emergence spray by boom sprays or aircraft. Spray oils such as Hasten, Uptake and DC-Trate improve weed control by 10% but may result in more crop retardation, however this rarely affects yield. Plants under drought stress are very difficult to kill with Cheetah. Ryegrass or wild oat plants in the two leaf stage are more susceptible to Cheetah than older or younger plants. The addition of zinc (as zinc oxide or Twin Zinc) may reduce the crop retardation effects but usually decreases the level of weed control by about 5%. Use only where zinc problems are expected.
Aim to apply the spray as close a possible to the growing point of the plant as movement from the sprayed leaves to the site of action at the growing point can be limiting.
8 WEATHER:
Rainfast in 4 hours.
Frost effects: Successful control has been achieved on dewy and frost covered crops but it is recommended to avoid these conditions if possible. Frosts during and after application have only had minor effects on weed control but should be avoided if possible. Extended periods of frost reduce plant vigour and result in poorer results.
Frost free days required after application: 1 day.
Wind: 2-25 kph preferred. Avoid spraying in still conditions unless there is no inversion.
Inversions: Avoid spraying under inversion conditions
Temperature:
Delta T and relative humidity: Avoid application when Delta T is greater than
Soil moisture at application: Best results when soil is moist and rain follows in a day or two.
Crops damaged by hail, wind or sand blast may be more severely affected than healthy crops.
9 ADJUVANTS:
Wetting agents: Generally improve weed control.
Spray oils: Generally improve weed control but may result in more crop symptoms and possible yield reductions.
10 WATER QUALITY:
Use mixed spray immediately if water quality is poor.
Hard water: Hardness of less than 1000 ppm is OK. Avoid very alkaline or acid water.
Saline water: No effect.
Colloids:
pH: Diclofop is unstable in alkaline conditions and sethoxydim is unstable in acid conditions. A pH of 7 is preferred.
Tank life: Use within 6 hours of mixing.
11 COMPATIBILITY:
Trace elements.
Compatible with Twin Zinc.
Not compatible with other zinc and nitrogenous foliar fertilisers.
Hormonal herbicides such as 2,4-D are antagonistic. 2,4-D decreases the conversion to the active form, decreases translocation of diclofop, increases the rate of detoxification and competes at the fatty acid synthesis level. Plants treated with 2,4-D up to two weeks before or after application may be less susceptible to application. MCPA antagonism is different and appears to be caused by reactions outside the plant.
Wetting agents improve the absorption of diclofop by plants. Spraying oils also improve the translocation of Cheetah which improves weed control but often reduces the crops tolerance.
Compatible with Hasten, Uptake, DC-Trate, BS1000.
12 EQUIPMENT:
Boom sprays:
Carrier volume: 50-150 L/ha recommended on label. Use finer droplets if using down to 30 L/ha.
Nozzles: Flat fan. 200-300 micron VMD recommended on label. Use 200 if using low water volumes. 11001 to 11003 nozzles or equivalent are generally suitable.
Pressure: 150-400 kPa.
Droplet density: 25 - 50 droplets /cm2 preferred.
Air induction nozzles are not recommended.
Aircraft:
If applying by air then even distribution of spray is essential to reduce crop damage from overlaps. Use 30 L/ha water. A permit may be required.
13 SPRAYER DECONTAMINATION:
Clean Up:
Clean soon after spraying to reduce the risk of forming dried deposits that may be difficult to remove.
Remove filters and clean separately. Triple rinse with water or water plus 0.25% wetting agent and run through boom.
Decontamination:
Remove filters and clean separately.
Rinse with water and drain.
Quarter fill the tank with an alkali detergent (eg 500 mL or g of Drive, Dynamo, Omo, or Surf per 100 L water) and circulate for at least 15 minutes then run through boom. Rinse twice with water.
Chlorine based cleaners are NOT recommended.
14 HERBICIDE RESISTANCE:
Ryegrass and wild oats that are tolerant to diclofop occur naturally at low levels. After many annual applications of Cheetah a significant level of tolerance would be expected if no other form of weed control was practiced.
15 REPLANTING INTERVALS:
Crop
Time
Maize
10 weeks
Sorghum
10 weeks
Rice
10 weeks
Broad leaved plants
0
16 WITHHOLDING PERIODS:
Crop
Type
Time
All
Harvest
Not required
All
Grazing
7 weeks
17 RE-ENTRY PERIOD:
Wear protective if entry to the crop is necessary before the spray has dried.
18 PROTECTIVE CLOTHING:
Wear a face shield or goggles when handling the concentrate.
19 SOIL:
Soil texture: No specific effect.
Soil pH: No effect unless it affects plant growth.
Soil organic matter: No effect unless it affects plant growth.
Crops on soils with marginal trace element status may be adversely affected. Do not use on zinc deficient soils.
20 MODE OF ACTION:
Cheetah is absorbed through the foliage and roots of nearly all plants. It has some contact action and is also translocated. In susceptible plants it is converted to a biologically active form where it accumulates in the growing tips. Cell division and elongation are stopped resulting in the stunted appearance of treated plants. Membranes are disrupted giving a 'water soaked' appearance. Fatty acid synthesis is stopped resulting in the death of growing tips, hence leaves of treated grasses can be easily pulled from their sheaths. Plants tolerant to Cheetah appear to have a different fatty acid synthesis mechanism, degrade it more quickly and do not convert as much to the active form. It is normally, used as a post emergence herbicide but does have some pre emergence activity at high rates. Wild Oats and Annual Ryegrass germinating soon after spraying are often stunted.
Fenoxaprop-p-ethyl is quickly converted to the free D+ acid fenoxaprop which has herbicidal activity.
Uptake and translocation:
Shoot uptake mainly with some root uptake.
Diclofop-methyl is poorly translocated (95% is typically still in the sprayed leaf 96 hours after spraying. There is little translocation of root absorbed herbicide to the leaves.
Sethoxydim is absorbed through the leaves and roots. It is translocated up and down throughout the tops but little is translocated to the roots.
Fenoxaprop-p-ethyl is absorbed by the leaves and is poorly translocated however it is quickly converted to the more mobile free acid.
Physiological effects:
Yellowing, reddening, reduced root and shoot growth, death.
Residual Life and Breakdown:
Cheetah has a short residual life in the soil and may suppress weeds that germinate within a few days of spraying.
21 SELECTIVITY:
Crop tolerance:
Under good growing conditions the cereal biomass may be reduced for 2-3 weeks but the crop normally recovers by 6 weeks and yields are rarely reduced.
Crop yellowing following application is common. This is more pronounced on wet or waterlogged crops and lush crops. Tolerance is reduced if spray oils are used.
Crop tolerance is often marginal so avoid spray overlaps and avoid spraying out corners.
Don't apply with nitrogen based foliar fertilisers or where symptoms from foliar fertilisers are present.
Yield losses may occur in crops growing in soils with marginal trace element levels.
Varietal sensitivities:
Effect on Clover Species:
Little effect on Clovers.
Effect on Medic Species:
Little effect on Medics.
Effect on Lucerne:
Little effect on Lucerne.
Effect on Native Plants:
Most native plants tolerate Cheetah.
22 DISEASE AND INSECT EFFECTS:
Crops damaged by insects or diseases may be more severely affected than healthy crops.
23 PLANT SYMPTOMS:
Annual Ryegrass and Wild Oats stop growing soon after application. The leaves take on a water soaked or oily appearance within a few days. About a week later, leaves become red-brown in colour and may be easily pulled from their sheaths before dying. Plants that recover have severely reduced root systems.
SECONDARY EFFECTS:
24 TOXICITY:
Summary:
Toxic to aquatic organisms. Repeated exposure may cause allergic disorders.
Not mutagenic or teratogenic (i.e. does not cause reproductive problems). Low quantities of naphthalene are present in the product which is classed as a potential human carcinogen. Diclofop has caused increased in tumours in rodents by a mechanism that is not considered relevant in humans.
Acceptable Daily Intake (ADI) -
Other Species -
Dangerous to fish and aquatic organisms.
Birds: Low toxicity. Diclofop LD50 > 10000 mg/kg for Japanese quail. Sethoxydim LD50 > 5000 mg/kg for Japanese quail. Fenoxaprop-p-ethyl LD50 > 2000 mg/kg for Japanese quail. Mefenpyr-diethyl LD50 > 2000 mg/kg for Japanese quail.
Fish: High toxicity - LC50 - 0.24 mg/L for diclofop, 38-153 mg/L for sethoxydim, 0.39 mg/L for fenoxaprop-p-ethyl. 2.4-4.2 mg/L for mefenpyr-diethyl.
Invertebrates - High toxicity - Daphnia magna EC50 0.23 mg/L for diclofop, 1.5 mg/L for sethoxydim, 1.058 for fenoxaprop-p-ethyl. 53 mg/L for mefenpyr-diethyl.
Algae - High toxicity - LD50 - 1.5-5.8 mg/L for diclofop, 1.65-5.8 mg/L for mefenpyr diethyl. 0.54 mg/L for product.
Bees - Low toxicity for all active ingredients.
Earthworms - Low toxicity for all active ingredients.
If SWALLOWED - Rinse mouth with water. Do NOT induce vomiting. Give a glass of water if patient is fully conscious. If in EYES - Irrigate with plenty of water. See a doctor.
If on SKIN - Rinse with plenty of water, remove contaminated clothing, wash with soap and water.
If INHALED - Remove patient to fresh air. Apply artificial respiration if breathing stops and call a doctor.
Contact the Poisons Information Centre on 13 11 26.
Advice to doctor - Treat symptomatically.
27 ENVIRONMENTAL FATE:
The diclofop component of Cheetah is strongly adsorbed on soils. Its solubility provides a slight risk for movement into ground water under extreme conditions. It is broken down in plants. In soil, microbes break down diclofop with a half life of 1-57 days and a DT90 of 30-281 days. At higher pH and under anaerobic conditions the half life is increased. It has a low level of leaching (High Koc) and is not expected to enter groundwater. Diclofop is rapidly excreted from animals and does not move into milk or eggs. It is not degraded by light.
The sethoxydim component has a ready/inherent biodegradability (28d) <70%.
The Fenoxaprop-p-ethyl component is partially to moderately biodegradable. It has little leaching potential.
Mefenpyr-diethyl hydrolyses with a half life >365 days at pH 5, 40 days at pH 7 and 0.35 days at pH 9. It photo degrades with a half life of 2.9 days. In soil it has a half life DT50 of less than 10 days and is not leachable.
Hydrolysis: Diclofop-methyl is slowly hydrolysed.
Photolysis: Sethoxydim photolysis in water has a half life of less than 1 hour. Fenoxaprop-p-ethyl has a photolysis half life of less than a day. The free acid has a half life in water of 13-20 days.
It has a half life in soil of 1-57 days.
It has an EPA classification for soil mobility that ranges from
Ground water contamination is unlikely in all but extreme conditions.
Accumulation in milk and tissues - undetectable.
89% diclofop was excreted within 2 days in faeces and urine.
Sethoxydim is metabolised in animals.
80% fenoxaprop is excreted in 2 days in animals with almost complete excretion within 7 days.
28 REGISTERED CROPS:
See HerbiGuide Species Solution tab.
29 REGISTERED WEEDS:
See HerbiGuide Species Solution tab.
30 REGULATION AND LEGAL:
UN number: 3082.
CAS numbers: Diclofop-methyl 51338-27-3. Sethoxydim 74051-80-2. Fenoxaprop-p-ethyl 71283-80-2. Mefenpyr-diethyl 135590-91-9. Hydrocarbon solvent 64742-94-5 Naphthalene (in solvent) 91-20-3.
Hazchem code: 3Z.
NOHSC classification:
Land transport:
Dangerous goods class (ADG): Not a dangerous good.
Sea transport:
Proper shipping name: ENVIRONMENTALLY HAZARDOUS SUBSTANCE, LIQUID, N.O.S. (contains diclofop-methyl, fenoxaprop-p-ethyl), Packing Group III, UN 3082. SEVERE MARINE POLLUTANT.
International Maritime Dangerous Goods Code (IMDG):
Class: 9, PP
Packaging group: III
EPG:
Severe marine pollutant.
Risk phrases:
R21 - Harmful in contact with skin.
R36/38 - Irritating to eyes and skin.
R43- May cause sensitisation by skin contact.
R65 - Harmful: May cause lung damage if swallowed.
Octanol:Water ratio: LogPow = 4.5 for diclofop. LogPow = 4.51 for sethoxydim at pH 5 and 1.67 at pH 7. LogPow = 4.58 for fenoxaprop-p-ethyl. LogPow = 3.83 for Mefenpyr-diethyl at pH 6.3 and 21 C.
Soil organic carbon absorption coefficient (Koc):
Vapour Pressure: 0.3 kPa for solvent at 38 C.
Vapour density: > 1.0 for solvent.
Dissociation constant: pKa
Melting point: C.
Boiling point: 179-213 C.
Molecular weight:
Bulk density:
Specific gravity: 0.997 - 1.004 at 20 C.
pH: 5-6 in 1% solution.
Flammability: Combustible liquid, class C1. L.E.L. 0.6. U.E.L. 7.0 vol % in air (solvent)
Flashpoint: between 61 and 150 C.
Autoignition: >400 C.
Corrosivity:
Shelf Life: 3 years.
(When Stored under Ideal Conditions)
32 SPILLS:
Extinguish possible sources of ignition.
Absorb spill with earth, sand, clay or absorbent material.
Ventilate area after cleanup.
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.
Product will burn.
Hazchem code: 3Z.
34 COMMENTS:
Export tolerances and MRL's may not be established in some export markets. Check with Bayer before use on export crops.
35 REFERENCES:
Ashton, F.M. and Crafts, A.S. (1981) Mode of Action of Herbicides. (Wiley-Interscience publication).
Kearney, P.C. and Kaufman, D.D. (1976). Herbicides. Chemistry, degradation and mode of action. Vol 1 & 2.
Bayer (2007) MSDS and Label 60928/1207.
Acknowledgments:
Collated by HerbiGuide. For more information see www.herbiguide.com.au or phone 08 98444064.