Using Glyphosate
This fact sheet is part of a series designed
to help you:
■
increase your awareness of correct and
responsible use of all chemical types
■
gain the knowledge required to effectively
control weeds, pest insects and diseases without
damaging, contaminating or polluting our
environment
■
adopt best practice to minimise chemical use
and maximise personal safety, and
■
play a part in improving water quality and
environmental health.
What is Glyphosate
Glyphosate is one of the most widely used
herbicides.
It is a non-selective chemical that is effective on
a wide range of weeds. However, Glyphosate
will kill your garden plants if it comes into contact
with them.
This chemical is most effective against young,
actively growing plants, but needs to be used in
the correct way to achieve the best results. Field
evidence suggests that most people apply far more
chemical than is needed to kill the weeds being
targeted – up to five times as much as is necessary.
This is putting our environment, in particular our
precious water resources, at risk.
How it Works
Glyphosate is absorbed through plant leaves.
It is then carried by the sap stream into the plant
roots, where it prevents them from absorbing
nutrients from the soil – thereby killing the plant.
Annual weeds, including grasses and most
broad-leafed plants, are easily controlled using
Glyphosate. This is because they have soft tissue
and when growing actively they quickly absorb
enough chemical to destroy the plant.
However, weeds with bulbs and perennial weeds
with woody stems are much harder to control.
They will only die if sufficient chemical reaches
each plant’s root system.
In all cases, but particularly with bulbs and woody
weeds, timing of the spray application is critical.
More is Not Better
Glyphosate, like all registered herbicides, works
best when applied at the correct rates. Applying
more than is needed is not only unnecessary,
it also places you and the environment at risk.
Use the minimum amount of spray mix needed,
according to the directions on the label, to achieve
uniform coverage of the target foliage without
runoff.
For more information on how to calculate
the correct application rates, please refer to
another fact sheet in this series: Accuracy
and Effectiveness.
RESPONSIBLE CHEMICAL USE
Learning how to manage and handle chemicals safely and responsibly not only
ensures your personal protection, but also provides environmental protection for
our precious natural resources, like water, soils, native plants and animals,
marine and coastal environments.
Glyphosate is one of the most
widely used herbicides
Other fact sheets in this series
Accuracy and Effectiveness
Alternatives to Chemicals
Bait Station Safety
Best Time to Spray
Personal Safety
Weeds Near Water
Glyphosate is sold under a variety
of brand names, including:
■
Weedmaster Duo
®
■
No Grow
®
■
Zero
®
■
Round-up
®
■
Mitre 10 Glyphosate
®
Getting the Best Results
To get the best results from spraying with
Glyphosate make sure that:
■
plants are actively growing
■
there is plenty of fresh, green growth to absorb
enough of the spray mix to kill the plant – spray
only when there is enough foliage to ensure
adequate chemical intake
■
leaves are:
> free of dust or dirt
> not covered with heavy dew or frost
■
plants are not under stress due to:
> dry conditions
> waterlogging
> high temperatures (do not spray if the
temperature is over 25°C)
> low temperatures (do not spray until the day
temperature reaches 12°C)
■
water used for mixing is clean and free of dirt –
rainwater is best
■
spray equipment has the right nozzle and
operates at the right pressure to ensure good
coverage, and
■
no rain is expected for at least six hours.
Always put 80 per cent of the required water into
your clean sprayer before adding the chemical,
then slowly add the other 20 per cent of the
water. This avoids frothing of the spray mix.
Do not spray when there is a breeze that may
cause spray droplets to drift onto desirable plants,
including trees, or onto hard surface areas (paving,
pathways and driveways) where it may be washed
into the gutters and from there into local drains,
creeks and rivers.
If the breeze is strong enough to shake the foliage
of trees or bushes, it is probably too windy to
spray safely.
Give it Time to Work
Allow enough time after spraying with Glyphosate
for the chemical to be absorbed and do its work.
■
Do not pull, dig or mow weeds for a week
after spraying.
■
Do not respray because you fail to see an
obvious effect within just a few days.
■
With perennial weeds the visible effects of
spraying (gradual wilting and yellowing) may
not be evident for three weeks or more.
Dealing with Problem Weeds
The following guidelines for particular problem
weeds will help ensure that Glyphosate works
well for you without over using or respraying
unnecessarily.
Oxalis
■
For Oxalis (soursobs) the best results will be
achieved by spraying when the plants are about
one third in flower.
■
At this growth stage the chemical will be
effectively carried down to the bulbs of the
plants.
Perennial Plants
■
To kill perennial plants such as couch grass,
Glyphosate needs to be applied to fresh, actively
growing green vegetation with sufficient leaf
area to absorb enough chemical to kill the
whole plant.
■
Slashing or mowing and allowing ample
regrowth (good lush green growth 10 to
15cm long in the case of kikuyu or couch grass)
before spraying can improve the chances of
maximum control.
✓
✓
Do not spray when plants
are under stress
Spray only when there is
enough foliage to ensure
adequate chemical intake
Contacts
Adelaide and Mount Lofty
Ranges Natural Resources
Management Board
Gawler
Telephone 8523 7700
Lobethal
Telephone 8389 6166
Willunga
Telephone 8550 3400
Eastwood
Telephone 8273 9100
www.amlrnrm.sa.gov.au
If you are uncertain about any aspect of chemical use, please seek professional
advice from the place of purchase or the manufacturer before proceeding.
more is not better!When using chemicals
Disclaimer The advice contained in this publication is intended as a source of information only. While all due care has been
taken in compiling the information, we do not guarantee that this publication is without flaw and therefore disclaim any liability
for any errors or omissions, loss, damage or consequences which may arise from any information given in this publication.
