Midas is a broad spectrum, residual herbicide that is mainly used in IT (imidazolinone tolerant or ClearfieldTM) cereals. It is usually applied at the early post emergence stage and is absorbed through both leaves and roots.
7 APPLICATION METHODS AND TIPS:
For best results add a spray oil and apply during fine weather to actively growing plants. Moist soil conditions followed by rain a day or two after spraying is ideal.
Vigorous, dense crops will improve weed control and reduce seed set of weed that have been stunted rather than killed by the herbicide.
10 WATER QUALITY:
Hard water
Colloids
pH
11 COMPATIBILITY:
Trace elements.
14 HERBICIDE RESISTANCE:
Repeated applications are likely to lead to resistance in a number of grass species. The risk of resistance development in broad leaved weeds is reduced due to the dual mode of action provided by the group B components (imazapyr and imazapic) plus the group I component (MCPA) on these species. This product will not control or only provide partial control some group B tolerant weeds.
A best management practice has been developed for Midas to reduce the risk of resistance development and is available from BASF.
15 REPLANTING INTERVALS:
Rainfall from time of application to planting.
50-100 mm
100-150 mm
150-250 mm
more than 250 mm
Clearfield crops
Crops in Column 1
Crops in Columns 1&2
Crops in Columns 1-3
Chickpea
Lentil
Biserrula
Barley
Clover
Lucerne
Lupins
Durum Wheat
Faba Bean
Medic
Triticale
Field Pea
Serradella
Wheat
Vetch
Wheat and Triticale are more tolerant than Barley and Durum Wheat. Oats are sensitive to soil residues.
Chickpea, Faba Bean and Field Pea can be planted where interim rainfall is less than 50 mm or where replanting is required after crop failure.
Ensure adequate zinc nutrition where herbicide residues are likely to be present.
17 RE-ENTRY PERIOD:
24 hours.
Summary:
Details:
Poison schedule - S6.
Mammalian toxicity -
Acute oral LD50 - >2000 mg/kg (rats), [For comparison table salt is 3000 mg/kg] Harmful if swallowed. Midas contains an hydrocarbon solvents which present the major hazard.
Acute dermal LD50 - 1550 mg/kg (rabbit).
Skin - May irritate or damage skin.
Eye - Severely irritating. Will damage eyes.
Vapour inhalation - LC50 - >1.3 mg/L air (rat). Practically non toxic.
Chronic oral toxicity NOEL - ppm for two years.
Not mutagenic or teratogenic (i.e. does not cause cancer or reproductive problems).
Anaemia and liver effects have been seen at high doses and muscular effects at lower doses. No adverse effects are expected from use of the formulated product.
Other Species -
Birds - toxicity.
Fish - toxicity LC50 > ppm.
Invertebrates - toxicity.
Bees - toxicity.
18 PROTECTIVE CLOTHING:
Wear goggles or a face shield when handling the concentrate.
19 SOIL:
20 MODE OF ACTION:
Midas has a dual mode of action. The imazapyr and imazapic components inhibit the acetolactate synthase (ALS) enzyme that is involved in the production of three essential amino acids required for protein production. The MCPA component disrupts plant cell growth by mimicking plant hormones. This should lead to reduced risk of resistance development in broad leaved weeds but will not affect resistance risk in grass weeds.
Uptake and translocation:
The imazapyr component is absorbed mainly by the leaves with some absorbed by the roots. Imazapic is mainly absorbed through the roots with some absorbed through the leaves. MCPA is absorbed through the leaves.
Physiological effects:
Residual Life and Breakdown:
Selectivity:
23 PLANT SYMPTOMS:
Distortion of young growth due to the MCPA component usually occurs within a few days of spraying.
Young growth turns purple, red or yellow, 1-2 weeks after spraying, followed by tip death 2-4 weeks after spraying then death or stunting of the plant.
Winter growth of host plants may be reduced but usually recover by spring.
SECONDARY EFFECTS:
Canola, Cotton, fruit tree, Grapevines, Lupins, ornamentals and Tobacco are particularly sensitive to spray and vapour drift.
24 TOXICITY:
25 TOXICITY SYMPTOMS:
26 FIRST AID:
If in EYES - Wash eyes with water immediately. See a doctor if the irritation persists.
If SWALLOWED - Do NOT induce vomiting. See a doctor or ring the Poisons information centre on 131126.
If on SKIN - Wash immediately with soap and water. Remove contaminated clothing. See a doctor if irritation persists.
If INHALED - Remove patient to fresh air.
Advice to doctor - No specific antidote. Treat symptomatically.
27 ENVIRONMENTAL FATE:
It has a half life in soil that is longer in acid soils than in alkaline soils.
There is little or no hydrolysis.
It has an EPA classification for soil mobility that ranges from
Ground water contamination
Accumulation in milk and tissues.
28 REGISTERED CROPS: See HerbiGuide
29 REGISTERED WEEDS: See HerbiGuide
31 PROPERTIES:
Water solubility at 25 C. Emulsifiable.
Oil solubility - Soluble.
Octanol:Water ratio at 25 C. - at pH 5;
Vapour Pressure at 25 C. -
Dissociation constant - pKa
Melting point - C.
Molecular weight -
Half life in water - days at pH5 and 35 C.
Flammability - Not flammable.
32 SPILLS
Absorb with lime or wet with 5% soda ash (Sodium carbonate) and absorb on sand.
33 FIRE
Thermal decomposition may form oxides of carbon and nitrogen.
33 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.
NRA approval number: 52714.
Field Crop Herbicide Information:
Midas
2. Concentration of Active Constituent : Imazapyr 7.3 g/L plus imazapic 22 g/L plus MCPA ethyl hexyl ester 288.5 g/L.
Trade Name : Midas.
3. Formulation : Emulsifiable concentrate.
4. Poison Schedule : 6
6. Product colour :
7. Product Flammability : Not flammable.
8. Dangerous Goods Class : Not Applicable
9. Shelf Life : Several years.
10. Mixtures Compatibility : See HerbiGuide.
11. Registered Crop(s) : See HerbiGuide.
12. Effect of Soil Texture on Herbicide :
13. Effect of Soil pH on Herbicide : It tends to be more active on alkaline soils because it is more soluble in these conditions. This also means it breaks down more quickly due to microbial degradation on these soils also.
14. Effect of Soil Organic Matter on Herbicide :
15. Mode of Action : Group B ALS inhibitor and group I disrupts plant cell growth.
16. Application Timing : Early post emergence.
17. Rate Variations : See HerbiGuide.
18. Rates Selection : See HerbiGuide.
19. Weeds Controlled : See HerbiGuide.
20. Effect on Crop : Temporary yellowing and slowing of crop growth may occur but this rarely affects yield. It is most often seen when the crop is sprayed during poor growth conditions. Midas will seriously damage conventional cereals.
21. Effect on Legume Species : Reduced growth.
22. Soil Moisture at Application :
DRY - Reduced activity and poor residual control of germinating weeds.
MOIST - Ideal.
WATERLOGGED - Reduced activity if plants are stressed due to waterlogging.
23. Frost Effects : Do not apply to frost affected crops.
24. Frost Free Days Required After Application :
25. Effect of Application Water Quality on Herbicide :
Saline Water -
Soil Colloids -
26. Recommended Water Volume : at least 50 L/ha recommended by BASF.
27. Nozzle Type : Flat fan.
28. Recommended Nozzle Pressure : 200-300 kPa
29. Recommended Filter Size : 100 mesh or mesh size as suitable for nozzle being used.
30. Recommended Wetter:
31. Other Additives : Spray oil. BASF recommend Kwickinor Hasten.
32. Rain Fastness : 4-6 hours.
33. Time Interval Before Effect is Noticed : 3-10 days.
34. Weed Symptoms : Distortion, purple, red or yellow young growth followed by tip death then death or stunting of the plant.
35. Effect of Herbicide/Disease Interaction on Crop :
36. Withholding Period : 0-28 days. 37. Plant-Back Period : Immediate for IT tolerant cereals, Maize and Canola. 8 months for Lucerne, Lupins, Oats, pasture legumes and Vetch.
8 months if more than 250 mm rain has fallen between spraying and sowing for Barley, Triticale and Wheat.
22 months for Barley, Safflower, Triticale and Wheat.
34 months for Canola and all other crops.
Spray Tank Clean-Up : Drain tank and flush with soapy water (use 500g of Surf, Omo or Drive per 100 L water). Flush with clean water. Fill the tank with clean water and add 2 L household ammonia per 100 L water or a commercial boom cleaning agent. Rinse several times with clean water. Remove the nozzles and screens and clean separately.
39. Other Comments :
Numbered data adapted from "Crop Herbicide Information"
courtesy of A.J. Chambers, Vic. Dept of Food & Agric.
Acknowledgments:
Collated by HerbiGuide. For more information see www.herbiguide.com.au or phone 08 98444064.