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Corvus Herbicide

Corvus herbicide is a new corn herbicide for Eastern Canadian farmers that provides outstanding control of a broad spectrum of broadleaf and grass weeds in field and seed corn.

Corvus offers flexibility in application timing and tank mixing options to tailor your weed control to your needs, so you can get outstanding performance.

Product Summary

Product Type

Herbicide

Crops

Field corn
Seed corn

Weeds Controlled

Crabgrass (smooth and large/hairy)
Green foxtail1
Tall waterhemp

Groups & Active Ingredients

Thiencarbazone-methyl (Group 2)
Isoxaflutole (Group 27)

Formulation Type

Suspension concentrate

Packaging

4 x 4.0 L jugs
(a jug treats 30 ac. at the recommended mid-rate)

Product Highlights

Corvus is a new corn herbicide for use in Eastern Canada, providing solid control against a broad spectrum of broadleaf and grass weeds.

  • Delivers three levels of control to fight weeds: rapid burndown for emerged weeds, residual control to prevent newly emerging weeds, and reactivation with rain for prolonged weed control
  • Offers flexibility in application timing as it can be applied pre-emerge, pre-plant incorporated, or early post-emerge (up to 2-leaf)
  • Excellent resistance management tool and tank mix partner with Roundup® brands

Performance

Corvus weed control performance

28 days after application
50 55 60 65 70 75 80 85 90 95 100
Converge Flexx (20 ac.)
74%
Corvus (mid-rate)
78%
Primextra® herbicide (mid-rate)
75.2%
Integrity® herbicide
74.4%
Engarde™ Dry herbicide
68.1%
Corvus (mid-rate) + atrazine
91%
Acuron® herbicide
84.6%

Source: 2021 Bayer Eastern Canada Market Development Trials (n=5). A total of 21 weed hits, 15, broadleaves and 6 grasses. Predominate species being lamb’s-quarters (5), common ragweed (3) and yellow foxtail (3). Treatment means are significantly different at P<0.05. All treatments were applied pre-emerge. Your results may vary depending on agronomic, environmental and pest pressure variables.

Crops

  • Field corn
  • Seed corn

Effective Against

Grassy weeds controlled

  • Barnyard grass*,1
  • Crabgrass (smooth and hairy)*
  • Green foxtail*,1
  • Giant foxtail*,1
  • Yellow foxtail*,1
  • Witchgrass

Broadleaf weeds controlled

  • Common ragweed*
  • Dandelion (seedling)*
  • Eastern black nightshade*
  • Lamb's-quarters*
  • Mustard (wild and wormseed)*
  • Plantain (seedling)*
  • Redroot pigweed*
  • Sowthistle (annual and spiny annual)*
  • Tall waterhemp*
  • Velvetleaf

*including emerged weeds up to 5 cm in height; includes ALS/SU (Group 2), auxin (Group 4), triazine (Group 5), glyphosate (Group 9) and PPO (Group 14)-resistant biotypes

1 non- ALS/SU (Group 2) resistant biotypes only

How to Apply

  • Apply Corvus alone or in tank-mixtures, by ground equipment only. Do not apply with aerial application equipment.
  • Accurately calibrate the sprayer prior to mixing the herbicide treatments
  • Apply Corvus in a minimum of 150 L/ha (15 gal./ac.) of total spray volume. Sprayable fluid fertilizer (nitrogen solution) may replace all or part of the water as a carrier for pre-plant (surface or incorporated) and pre-emergence applications.
  • Refer to the nozzle manufacturer’s recommendations for proper nozzle, pressure setting and sprayer speed for optimum product performance and minimal spray drift
  • For best results use flat fan nozzles or comparable nozzles to achieve uniform spray distribution.  Do not apply with hollow cone nozzles or with other application equipment which does not provide uniform coverage.
  • Agitate thoroughly before and during application with either bypass or mechanical agitation

Re-crop Interval

Immediate plant back 4 months 10 months
Field corn
Seed corn
Winter wheat Soybeans
Spring wheat
Spring barley
Field corn
Seed corn

Application Rates and Guidelines

LOW RATE (jug treats 43 ac.)

  • 230 mL/ha (93 mL/ac.)  
    • Early-season control
    • Use in situations of low weed pressure and in a planned two-pass system 

MID RATE (jug treats 30 ac.)

  • 330 mL/ha (133 mL/ac.)
    • Our recommended rate for PPI, PRE and EPOST programs
    • Season-long control

HIGH RATE (jug treats 24 ac.)

  • 410 mL/ha (166 mL/ac.)  
    • Use in situations of heavy weed pressure
    • Will provide improved (over lower rates) control of tall waterhemp, large crabgrass and green foxtail

Corvus treatments are most effective in controlling weeds when adequate rainfall is received within 14 days after application.

Preplant/Preemergence Burndown-Spray Additives:

  • For control of emerged weeds prior to corn emergence, Corvus may be used in conjunction with an adjuvant: COC or MSO applied at 1% volume/volume or a non-ionic surfactant (NIS), such as Agral® 90 or Agsurf®, applied at 0.25% volume/volume

Early post-emergence to corn:

  • Do not use any adjuvants with Corvus when applied to emerged field corn

Pre-Harvest, Grazing/ Feeding and Re-entry Intervals

  • Do not graze or feed the immature corn to livestock prior to 45 days of Corvus application
  • If tank-mixing, always respect the maximum pre-harvest/-grazing interval stated on the labels of all the tank-mix products
  • Do not enter or allow re-entry into treated areas until 12 hours after application. Exception: If the product is soil-injected or soil-incorporated, workers may enter the treated area if there will be no contact with anything that has been treated.

Application Tips

  • Plant corn at least 4 cm deep.  Failure to close the seed furrow may allow herbicide spray to directly contact the seed which can cause injury.
  • Corvus treatments are most effective in controlling weeds when adequate rainfall is received within 14 days after application
  • For ground application:
    • For best results use flat fan nozzles or comparable nozzles to achieve uniform spray distribution. Do not apply with hollow cone nozzles or with other application equipment which does not provide uniform coverage.
    • Apply Corvus in a minimum of 150 L/ha (15 gal./ac.) of total spray volume. Sprayable fluid fertilizer (nitrogen solution) may replace all or part of the water as a carrier for pre-plant (surface or incorporated) and pre-emergence applications.
    • Accurately calibrate the sprayer prior to mixing the herbicide treatments
  • Do not use sprayable fluid fertilizer (nitrogen solution) as the carrier for early post emergence applications as the nitrogen solution can typically cause corn injury such as tissue burn (necrosis)
  • Do not use any adjuvants with Corvus when applied to emerged field corn
  • Do not apply Corvus to field corn grown on loamy sands or sands and/or soils with less than 2% O.M.

Water Volumes and Tank Mixing

Water Volumes

Corvus herbicide can be applied broadcast in a minimum of 150 L/ha (15 gal./ac.) of total spray volume. Sprayable fluid fertilizer (nitrogen solution) may replace all or part of the water as a carrier for pre-plant (surface or incorporated) and pre-emergence applications.

Rainfastness

Rainfast 2 hours after application

Tank Mixing Procedure

Refer to product label

Tank Mix Flexibility

Corvus is an ideal tank-mix partner for:

  • Roundup® Transorb® HC liquid herbicide
  • Roundup WeatherMAX® with Transorb® 2 Technology liquid herbicide
  • Roundup Xtend® with VaporGrip® Technology1,2
  • XtendiMax® with VaporGrip® Technology2
  • Atrazine

1Use in corn hybrids with Roundup Ready® 2 Technology only.

2Do not tank mix these products with UAN or an additional adjuvant

How to Manage Resistance

Resistance Management

Please note that Corvus is both a Group 2 and a Group 27 herbicide. Any weed population may contain or develop plants naturally resistant to Group 2 and/or Group 27 herbicides.

To Delay Herbicide Resistance:

Where possible, rotate the use of Corvus or other Group 2 and/or 27 herbicides within a growing season (sequence) or among growing seasons with different herbicide groups that control the same weeds in a field.

Use tank-mixtures with herbicides from a different group when such use is permitted. To delay resistance, the less resistance-prone partner should control the target weed(s) as effectively as the more resistance-prone partner.

Herbicide use should be based on an integrated weed management program that includes scouting, historical information related to herbicide use and crop rotation, and considers tillage (or other mechanical control methods), cultural for example, higher crop seeding rates; precision fertilizer application method and timing to favour the crop and not the weeds), biological (weed-competitive crops or varieties) and other management practices.

Monitor Weed Populations

After all herbicide applications check weeds in your fields for signs of resistance development (for example, one weed species on the herbicide label may not be controlled). If resistance is suspected, prevent weed seed production in the affected area if possible by an alternative herbicide from a different group. Prevent movement of resistant weed seeds to other fields by cleaning harvesting and tillage equipment and planting clean seed. Have suspected resistant weed seeds tested by a qualified laboratory to confirm resistance and identify alternative herbicide options.

Advice

Contact your local extension specialist or certified crop advisors for any additional pesticide resistance-management and/or integrated weed-management recommendations for specific crops and weed biotypes.

For further information or to report suspected resistance contact Bayer via phone at 1-888-283-6847.

Provinces of Registration

  • New Brunswick
  • Newfoundland
  • Nova Scotia
  • Ontario
  • Prince Edward Island
  • Quebec
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