application of Roundup Transorb® HC or Roundup WeatherMAX® herbicide can help growers address many challenges that they
may be faced with as they prepare for harvest.
Perennial Weed Control
Perennial weeds are formidable
crop competitors, consuming moisture and nutrients from your fields throughout
the season. This is especially true
in years where crops may not have had the ability to out-compete weeds
throughout the season.
Pre-harvest is the best time to
control Canada thistle, quackgrass, perennial sow thistle, dandelion, toadflax
Ensure proper weed staging; dandelions should be at the
bud to bloom stage and Canada thistle at bud
or beyond. In all cases, the
leaves of the target weeds should be green and actively growing at the time of
Crop Staging is Critical
Physiological maturity is the key for timing a pre-harvest
glyphosate application. Physiological maturity is reached once seed moisture
content is less than 30%. The
following table provides visual indicators of physiological maturity:
||Visual test for 30% moisture content
dough stage; thumbnail impression remains on seed
are green to yellow; most seeds are yellow to brown
(75 to 80%) of pods are brown
(75 to 80%) of pods turned colour
pods (15%) are brown; seeds rattle
| Dry beans
are green to brown; pods are mature (yellow to brown); 80-90% leaf drop
|| Stems are green to brown; pod tissue is dry and brown;
80-90% leaf drop
||3 to 7 days before last cut in final year of stand
The ONLY registered
pre-harvest rate of Roundup Transorb HC or Roundup WeatherMAX herbicide is 0.67 L/ac.
An application greater than 0.67
litres per acre risks exceeding the MRL (maximum
residue limit) which can result in lost market options, both domestic and
export. MRLs are established by Health
Canada as part of the assessment process prior to the registration of a
pesticide and are regulated by the Pest Control Products Act1. Spray on label to
ensure you do not exceed the MRL.
Best Management Practices:
A minimum 5 gallons per acre is required to penetrate the crop canopy and
to ensure good coverage of the weeds and the crop. Use up to 10 gallons of water
per acre when the crop canopy is heavy or if your target weeds are sheltered by
the crop - especially important when targeting dandelions.
Crop that have been treated with
Roundup Transorb HC or Roundup WeatherMAX
herbicide in a pre-harvest application can be fed to livestock. Allow seven days between application and
grazing to allow the glyphosate to translocate within the target plants.
Stubble may be grazed immediately after harvest.
Crops for seed production:
Pre-harvest applications are not
recommended on crops grown for seed, as a reduction in germination may occur. Pre-harvest applications for lentils,
malt barley, and in some cases oats,
need approval from the grain buyer.
Straight cut recommendations:
Swathing can be eliminated when a
pre-harvest herbicide application is used on wheat, barley, oats, peas and flax. The crop can be straight cut 7 days after
If swathing after a pre-harvest
treatment, wait 3 full days (72 hours) after application to allow thorough
translocation for long-term weed control.
Heat® LQ herbicide is now registered as a pre-harvest tank-mix option
with Roundup Transorb HC or Roundup WeatherMAX
on canola, dry common beans, field peas and soybeans. More information on this
registration can be found at agsolutions.ca/HeatLQPreHarvest.
A pre-harvest weed control application is an excellent management strategy
to not only control perennial weeds, but to facilitate harvest management and
get a head start on next year’s crop. For more information on
pre-harvest applications, or to download our Preharvest Staging App, visit Roundup.ca/en/preharvest. For technical support, contact
Monsanto’s CustomCare® line at 1-800-667-4944.
Source: 1Health Canada (2012). Maximum Residue Limits for Pesticides. Verified (July 25, 2014) www.hc-sc.gc.ca
Click Here to Download the PDF version of this Technical Bulletin
ALWAYS READ AND FOLLOW PESTICIDE LABEL DIRECTIONS. Tank mixtures: The
applicable labeling for each product must be in the possession of the user at the time of application.
Follow applicable use instructions, including application rates, precautions
and restrictions of each product used in the tank mixture. Monsanto has not
tested all tank mix product formulations for compatibility or performance other
than specifically listed by brand name. Always
predetermine the compatibility of tank mixtures by mixing small proportional
quantities in advance. CustomCare®, CustomCare and Design®, Monsanto and Vine Design®, Roundup Transorb® and Roundup WeatherMAX® are registered trademarks of
Monsanto Technology LLC, Monsanto Canada, Inc. licensee. All other trademarks are the property of
their respective owners. ©2015 Monsanto Canada Inc.