Glyphosate Potassium Salt
1 Trade nameManufacturerForm
BIOTIS HI-LOAD HERBICIDEBIOTIS LIFE SCIENCE PTY LTDAC
CONCENTRATE ROUNDUP POWERMAX WEEDKILLERMONSANTO AUSTRALIA LTDAC
COUNTRY GLYPHOSATE 540 HERBICIDEACCENSI PTY LTDAC
FIREBOLT HERBICIDESIPCAM PACIFIC AUSTRALIA PTY LTDAC
RHODIA GLYPHOSATE POTASSIUM HIGH LOAD HERBICIDERHODIA AUSTRALIA PTY LIMITEDAC
ROUNDUP POWER MAX HERBICIDE BY MONSANTOMONSANTO AUSTRALIA LTDAC
RYGEL CLEARUP IMPRESS 540 HERBICIDERYGEL AUSTRALIA PTY LTDAC
TOUCHDOWN HITECH HERBICIDESYNGENTA CROP PROTECTION PTY LIMITEDEC

3 ACTIVE INGREDIENTS: 500-540 g/L Glyphosate potassium salt.

4 CHEMICAL GROUP: M.

Phosphonate or Glycine
FORMULATION: Water soluble.
5 RELATED HERBICIDES: None
6 GENERAL DESCRIPTION:

Glyphosate is the most widely used herbicide ever developed.

It is a non selective, leaf absorbed, translocated herbicide. Its main uses are for total vegetation control (eg. before planing crops or in industrial areas) and controlling the seed set of annual weeds. It is particularly effective on perennial weeds. It is of low toxicity to mammals, birds and fish. It presents virtually no environmental hazard.

Some plants have become resistant to glyphosate.

7 APPLICATION METHODS AND TIPS:

Glyphosate is applied by hydraulic nozzles or CDA (Controlled Droplet Application) equipment mounted on air craft or ground vehicles for broadcast application. It is usually mixed with water. Its low toxicity (to the operator) makes it ideal for directed application using hand held equipment.

Various wick type applicators have been developed for applying concentrated glyphosate solutions.

Glyphosate is most effective when applied on warm, sunny days when the plants are growing vigorously.

Drought or nitrogen stressed plants are difficult to kill with glyphosate.

Plants covered with dust are often hard to kill because the glyphosate attaches to the clays before entering the leaf.

If plants have been heavily grazed or defoliated they should be allowed to regrow until the root:shoot ratio is around 1 before application of herbicide or the rate of herbicide may need to be increased to achieve effective control.

Whilst glyphosate is not regarded as a soil residual herbicide, it appears to reduce germination of grasses for a few days after spraying. This may be due to direct contact of the herbicide on surface seeds.

Glyphosate reacts with calcium and other di and tri valent ions in water. 50 ppm calcium will reduce activity (Shea and Tupy, 1984). The ions form a complex chelate type structure with glyphosate which reduces absorption (Thelen et al, 1995). This antagonism may be reduced by adding crystalline sulphate of ammonia at a rate of 1 kg per 100 L of water.

Do not store in galvanised or mild steel containers.

9 ADJUVANTS:

Pulse may increase the activity of glyphosate on broad leaved species but often reduces its activity on grasses. It may also improve the rainfastness on some species. It usually shows greatest benefit on large broadleaved species such as Bracken, Blackberry and Gorse.

11 COMPATIBILITY:

Glyphosate combines (chelates) with di and trivalent ions. Copper, zinc, manganese, calcium and magnesium seriously reduce the effectiveness of glyphosate. This chelation is related to pH and acidifiers can be used to reduce problems with hard water. Slightly salty water and phosphates have little effect on glyphosate activity.

Plant hormonal herbicides, like 2,4-D, generally reduce the absorption and translocation of glyphosate.

Spraying oils, non-ionic wetting agents, ammonium sulphate and ammonium nitrate are usually compatible with glyphosate. On some perennial plants, these adjuvants may increase the efficacy of glyphosate considerably. On annual plants it is usually more cost effective to use extra glyphosate rather than adjuvants.

Glyphosate increases the absorption of imazethapyr (Spinnaker) Starke and Oliver 1998.

14 HERBICIDE RESISTANCE:

In 1996, annual ryegrass populations tolerant to glyphosate were discovered in Australia. Practices to reduce the development of herbicide resistance should be integrated into systems reliant on glyphosate.

Crops tolerant to glyphosate can be produced by genetic engineering.

18 PROTECTIVE CLOTHING:

Wear safety goggles when handling concentrate.

Avoid breathing spray mist.

20 MODE OF ACTION:

Glyphosate is slowly absorbed through the foliage and translocated to growing parts of the plants. It inhibits an enzyme in the shikimic acid pathway which reduces the supply of aromatic amino acids (phenylalanine, tryptophan and tyrosine) and consequently stops protein synthesis. It also affect potassium metabolism. Affected plants turn yellow because no new green chlorophyll is produced. Absorption of glyphosate is reduced in plants with waxy, thick or dehydrated cuticles. Thus, water stressed plants absorb less glyphosate. Surfactants, oils, ammonium, sodium or potassium ions increase absorption but have a variable effect on phytotoxicity because of their variable effects on translocation.

Glyphosate absorption is increased at high relative humidity and at high spray concentrations (low water volumes). Under low relative humidity conditions, at the time of application, additional surfactant often improves efficacy. Rain within 6 hours of application will wash glyphosate off the foliage. Most of the herbicide is washed off by the first 4 mm of rain. Translocation in the plant parallels the movement of assimilates. Good growing conditions result in good absorption, translocation and phytotoxicity. Temperature has little effect apart from its indirect effect on growth.

About twice the normal rate of glyphosate is required to kill plants suffering mild water stress and 10 times the normal rate is required for severely stressed plants.

23 PLANT SYMPTOMS:

Typically, young growth becomes yellow 7 to 14 days after application followed by older growth and then death of the plants. On broadleaved perennials there is often inter venal yellowing, sprouting of secondary buds and compact new growth that looks like 'witches brooms'. These grow for a period then yellow and die as glyphosate is translocated from within the plant to these new sites of growth. This may occur many months after treatment.

SECONDARY EFFECTS:

Glyphosate affects the growth regulating hormone (IAA) in plants. This stimulates the growth of secondary buds and causes abnormal growth.

Perennial broad leaved plants often produce growth that looks like a 'witches broom'. It has been reported to affect Rhizobium symbiosis with legumes. Field trials in Australia indicate that this is not likely to cause problems with normal application rates and use patterns.

24 TOXICITY:

Mammalian toxicity - low.

Acute oral LD50 - 2814-5000 mg/kg [for comparison salt is about 3000 mg/kg]

Acute dermal LD50 - > 5000 mg/kg

Skin - slightly to moderately irritating (formulated product)

Eye - severely irritating (formulated product). Will damage eyes.

Vapour inhalation - N.E.L. 12.2 mg/L air

Chronic oral toxicity - > 2000 ppm over 90 days

300 ppm over 2 years.

Birds - almost non toxic.

Fish - almost non toxic to slightly toxic.

Invertebrates (eg. Marron) - low.

Bees - low toxicity.

25 TOXICITY SYMPTOMS:

Glyphosate does not usually cause any symptoms because of its low toxicity. Some of the formulating agents may irritate eyes and skin causing a rash if the product is misused. Gastrointestinal discomfort, nausea, vomiting and diarrhoea have been reported and are probably caused by the surfactants in many formulations.

In sulphite sensitive people skin reactions have been reported following dermal exposure. Respiratory reactions have been reported after eating food or inhaling medications containing sulphiting agents as preservatives. People with asthma may be more prone to these reactions.

26 FIRST AID:

Contact a doctor or Poisons Information Centre on 13 11 26.

If Swallowed - Rinse mouth with water. Give a glass of milk or water. Do not induce vomiting. Contact a doctor or Poisons Information Centre.

NEVER GIVE ANYTHING BY MOUTH TO AN UNCONSCIOUS PERSON.

If on Skin - Remove contaminated clothing. Wash skin thoroughly with soap and water.

If in Eyes - Flush with water for 15 minutes. Contact a doctor immediately.

If Inhaled - Remove patient from contaminated area to fresh air.

Advice to doctor.

Do not induce vomiting owing to possible irritant side effects. If further treatment advice is required, contact 1800 033 111

27 ENVIRONMENTAL FATE:

Glyphosate is inactivated on contact with clay particles. This bonding is so strong that glyphosate appears to be non residual and does not move through the soil. Microflora degrade glyphosate under both aerobic and anaerobic conditions at variable rates. This results in a half life ranging from a few days to over a year. Chemical and photolytic degradation are usually negligible though some photolytic degradation has been reported in water.

There is little risk of Glyphosate contaminating water unless it has been applied directly to streams or washed off foliage hanging over streams.

In flowing irrigation channels, up to 50% of the glyphosate applied directly to the water has moved 2 to 10 Km downstream.

Glyphosate is not degraded by the higher plants or animals. It is not accumulated in the tissues of land or aquatic animals. It is accumulated in plant tissues and especially in the storage organs such as tubers, bulbs, rootstocks and rhizomes.

Glyphosate is expected to have little or no lasting effect on ecosystems because of its strong binding to clay, low mobility, low volatility, rapid degradation by common micro organisms and low toxicity to animal systems.

31 PROPERTIES:

Water solubility at 25 C. - 1.16 g/100 mL;

Oil solubility - Not soluble in oils.

Octanol:Water ratio at 25 C. - at pH 5;

Vapour Pressure at 25 C. - Non volatile.

Dissociation constant - pKa

Melting point - C.

Molecular weight -

Half life in water - days at pH5 and 35 C.

Combustible.

32 COMMENTS:

Only store in Stainless steel, aluminium, fibreglass or plastic lined containers. Do not expose glyphosate to galvanised or mild steel containers or pipes. It will react, producing hydrogen gas, which may form an explosive mixture capable of causing serious personal injury.

GLYPHOSATE

2. Concentration of Active Constituent : 450 g/L

4. Poison Schedule : 5
6.Colour : Blue
7.Flammability : Non flammable.
8.Dangerous Goods Class :
10.Mixtures Compatibility :
2,4-D ester (eg Ester 800) Glean (chlorsulfuron)

Ally (metsulfuron-methyl) Logran (triasulfuron)

atrazine (flowable) simazine (flowable)

dicamba (Banvel) Insecticides - refer label

Do NOT mix with:- Wettable Powder formulations.

Tank mixes with residual type herbicides such as substituted ureas, triazines, or others may decrease the activity of glyphosate. The addition of crystalline ammonium sulphate will assist to overcome the antagonism with triazines.
11.Registered Crop(s) : Pre-plant to all crops and pastures.
12.Effect of Soil Texture on Herbicide : Not relevant.
13.Effect of Soil pH on Herbicide : No effect.
14.Effect of Soil Organic Matter on Herbicide : Not relevant.
15.Mode of Action : Foliar translocation, root uptake is precluded by soil inactivation of glyphosate. Inhibits amino acid and protein synthesis. Post-emergent, non selective.
18.Rates Selection : Lower rate grasses prior to tillering, broadleaf weeds under 10-15 cm diameter/high. Higher rates for grasses after tillering, broadleaf weeds over 10 -15 cm diameter/high and perennial weeds.
19.Crop Damage (Crop Tolerance) : Not relevant.
20.Effect on Crop : Not relevant.
21a. Effect on Clover Species : Sub. clover - when applied in spring as a 'pasture topping' operation it can reduce seed set. In paddocks with low clover seed reserves, regeneration of plants the following season may be reduced. Established plants can be killed at 1 L/ha.

21b. Effect on Medics : Burr medic - very sensitive when the plant has abundant green leaf. Seedlings are sensitive. Tolerant when fully dormant (eg dry summer conditions).

21c. Effect on Lucerne : Effects on established plants have been variable. At rates recommended on established pastures for 'pasture-topping' the effect on lucerne is generally acceptable. At increasing rates of product adverse effects on plants have been observed with unacceptable damage frequently occurring.
22.Soil Moisture at Application :
DRY - Decreased efficacy as plants stressed.

MOIST - Good result.

WATERLOGGED - Can 'stress' weeds and hence slow or reduce result.
23.Frost Effects : Frost preceding application can reduce efficacy, allowing plants to regrow.
24.Frost Free Days Required After Application : Not relevant.
25.Effect of Application Water Quality on Herbicide :
Saline Water - no problem if monovalent cation. Avoid hard water with di- and tri-valent cations.

Soil Colloids - can reduce efficacy due to tie-up of active ingredient. Avoid using excessively dirty water.
26.Recommended Water Volume : 30 - 100 L/ha boom.
27.Nozzle Type : Flat fan.
28.Recommended Nozzle Pressure : 240 - 280 kPa (35 - 40.6 psi).
29.Recommended Filter Size :
30.Recommended Wetter : Non-ionic surfactant
Activator 90 - 125 ml/100 L. Agral 600 - 300 ml/100 L. Nufarm Surfactant - 300 ml/100 L. BS 1000 - 200 ml/100 L. Plus 50 - 400 ml/100 L. Turbo - 300 ml/100L.
31.Other Additives : Ammonium Sulphate (Boost or Liase). Must be free of metallic contaminants or the enhancement of glyphosate will not occur.
32.Rain Fastness : 6 hours.
33.Time Interval Before Effect is Noticed : 2 - 4 days annuals, 7 - 10 days perennials. Cool or cloudy weather following application may delay appearance of visible effects.
34.Plant Symptoms : Visual symptoms develop slowly and are:

1.Wilting, chlorosis and necrosis of young foliage which slowly spreads to older foliage.

2.The regrowth of perennial plants may be distorted with wrinkled or deformed leaves.
35.Effect of Herbicide/Disease Interaction on Crop : Not relevant.
36.Withholding Period : None.
37.Plant-Back Period : No plant-back period, but at least 1 day delay recommended before planting to allow complete translocation of the herbicide within the plant. Observe 2,4-D, Banvel, and Glean plant-backs periods if tank mixed.
38.Spray Tank Clean-Up : Flush with water.
39.Other Comments : If there is a lot of organic matter on soil surface, problems with microbial toxins and nutrient tie-up may be encountered. Emerging plants may be affected. Do NOT hold spray mixtures in galvanised or unlined steel containers (except stainless steel) for extended periods. Product or spray solutions react with galvanised or unlined steel containers or spray tanks producing hydrogen gas that may form a highly combustible gas mixture that can flash or explode if ignited by open flame, spark, welder's torch, lighted cigarette or other ignition source.
Numbered data from "Crop Herbicide Information"

courtesy of A.J. Chambers, Vic. Dept of Food & Agric.

33 REFERENCES:

Starke R.J. and Oliver L.R. (1998) Weed Science 46:652-660.

Acknowledgments:

Collated by HerbiGuide. For more information see www.herbiguide.com.au or phone 08 98444064.