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Publication 75S - 2007
Chapter 9. Corn (Field, Seed and Sweet)

Author: OMAFRA Staff
Creation Date: 23 May 2007
Last Reviewed: 23 May 2007
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Table of Contents

  1. New Products: Impact
  2. Table 9-1.Herbicide Weed Control Rating for Field Corn
  3. Postemergence Tank-mixes: Impact + Frontier + Atrazine
  4. New Products: IPCO Logic M
  5. New Products: Vantage Plus Max
  6. Corrections: Accent Total and Ultim Total
  7. Label Expansions: Accent 75DF and Peakplus
  8. Weed Control Rating Revisions
  9. Maximum Leaf Stage Revisions
  10. PDF Format
  11. Publication 75, Guide to Weed Control
  12. Related Links
  13. For more information

 

New Products:

  • Impact is a new broadleaf and grass herbicide for use only in field corn that is to be tank-mixed with Frontier and atrazine.
Table 9-1. Herbicide Weed Control Rating for Field Corn
Postemergence Tank-mixes
Grasses
Trade Name Barnyard Grass Crabgrass Fall Panicum foxtail, giant Green Foxtail foxtail, yellow Witch Grass Proso Millet
Impact + Frontier + Atrazine 9* 9* 9* 8 9* 9* 9* ?

? - Insufficient information available to make a rating.
* - Ratings with an asterisk indicate the weed is listed on the product label for control or suppresssion.

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Annual Broadleaf
Trade Name Wild buckwheat Cocklebur fleabane, Canada Lady's-thumb Lamb's-quarters mustards
Impact + Frontier + Atrazine ? ? ? 9* 9*

9*

More

Annual Broadleaf (con't)
Trade Name Annual Nightshade Pigweeds Commom Ragweed ragweed, giant Velvetleaf
Impact + Frontier + Atrazine 9* 9* 9* ? 7*

? - Insufficient information available to make a rating.
* - Ratings with an asterisk indicate the weed is listed on the product label for control or suppresssion

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Perennials
Trade Name bindweed, field horsetail milkweed nutsedge Quackgrass sow-thistle thistle, Canada
Impact + Frontier + Atrazine ? ? ? ? ? ? ?

? - Insufficient information available to make a rating.

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Crop Tolerance
Trade Name Crop Tolerance
Impact + Frontier + Atrazine E

Crop tolerance rating: E - Excellent, G - Good, F - Fair, P - Poor

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Postemergence Tank-mixes
Impact + Frontier + Atrazine
Trade Name Impact Frontier Atrazine Atrazine+ Assist + liquid urea ammonium nitrate (UAN)
Active Ingredient
topramezone
dimethenamid
atrazine
atrazine
Formulation
336 g/L
900 g/L
480 g/L
90 WG
Rate per hectare (active)
12.5 g/ha
1,000 g/ha
500 g/ha
Rate per hectare (product)
0.037 L/ha
1.11 L/ha
1.04 L/ha
0.556 kg/ha + 12.5 L/ 1,000 L + 12.5 L/ 1,000 L
Rate per acre (product)
15 ml/ac
0.45 L/ac
0.42 L/ac
0.225 kg/ac + 12.5 L/ 1,000 L + 12.5 L/ 1,000 L
Precautions:
  • Apply postemergence, up to 4 leaf grassy weeds, up to 8 leaf broadleaf weeds.
  • Apply between the spike and 3 leaf stage of corn.
  • Do NOT use on sweet or seed corn.
  • Do NOT use on corn hybrids less than 2700 CHUs.

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New Products:

  • IPCO Logic M (450 g/L) is a generic bromoxynil/MCPA product that has the exact same use rates and registrations in field corn as Badge and Mextrol (refer to * text in the table below for use rates).
Postemergence Broadleaf Herbicides
Buctril or bromoxynil/ MCPA
Trade Name Buctril IPCO Logic M*
Active Ingredient
bromoxynil/ MCPA
bromoxynil/ MCPA
Formulation
560 g/L
450 g/L
Rate per hectare (active)
0.56 kg/ha
0.56 kg/ha
Rate per hectare (product)
1 L/ha
1.25 L/ha*
Rate per acre (product)
0.4 L/ac
0.5 L/ac*

Precautions:

  • Apply from the 4-6 leaf stage but injury may occur if applied after the 6-leaf stage.
  • Controls most annual broadleaf weeds up to the 4-leaf stage.
  • Lamb's-quarters and mustard are controlled up to the 8-leaf stage
  • Do NOTuse on seed or sweet corn.*

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New Products:

  • Vantage Plus Max (480 g/L): A new glyphosate product registered for use in "Roundup Ready" corn (see * text in the table below for use rates).

Postemergence Grass and Broadleaf Herbicides
glyphosate
Trade Name glyphosate** glyphosate** glyphosate**
Active Ingredient
glyphosate
glyphosate
glyphosate
Formulation
360 g/L
480 g/L
540 g/L
Rate per hectare (active)
0.9 kg/ha
0.9 kg/ha
0.9 kg/ha
Rate per hectare (product)
2.5 to 5 L/ha
1.875 to 3.75 L/ha*
1.67 to 3.34 L/ha
Rate per acre (product)
1 to 2 L/ac
0.75 to 1.5 L/ac*
0.67 to 1.34 L/ac
**Numerous glyphosate products with this concentration exist. See Table 4-2 of this supplement for a complete list of Trade Names associated with this active ingredient

Precautions:

  • Use ONLY with pedigreed (certified) corn seed designated as "Roundup Ready Corn".
  • The initial application is recommended between the 2-6 leaf stage to remove early season competition. A second application at the low use rate may be applied up to the 8 leaf stage of corn.
  • Use the high rate for perennial and difficult to control weeds up until the 6 leaf stage of corn.
  • Use 100-200 L/ha (40-80 L/ac) of water.

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Corrections:

  • Accent Total and Ultim Total: Incorrect rate of 28% UAN. See * text in the table below for correct use rates of 28% UAN.

Postemergence Grass and Broadleaf Herbicides
Accent Total (Accent + Disctinct + non-ionic surfactant + UAN)
Trade Name Accent Distinct + non-ionic surfactant +liquid urea ammonium nitrate (UAN)
Active Ingredient
nicosulfuron
diflufenzopyr/ dicamba+ non-ionic surfactant + urea ammonium nitrate
Formulation
75 DF
70 WG
Rate per hectare (active)
25 g/ha
0.2 kg/ha + 0.25% v/v + 1.25% v/v
Rate per hectare (product)
33 g/ha
0.285 kg/ha + 2.5 L/1,000 L + 12.5 L/1,000 L*
Rate per acre (product)
13 g/ac
0.115 kg/ac + 2.5 L/1,000 L + 12.5 L/1,000 L*

Precautions:

  • Apply to active growth stage of seedling broadleaf weeds (less than 5 cm tall).
  • Apply to annual grasses in the 1-6 leaf stage and to quackgrass in the 3-6 leaf stage (10-20 cm).
  • Apply when corn is in the 2-8 leaf stage.
  • Apply when temperatures above 4 are predicted for the 24 hours before and after application.
  • Do NOT use on seed corn or sweet corn.*
  • Acent Total is co-pack of Accent and Distinct
  • 1 bag of Accent Total treats 10 acres.

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Postemergence Grass and Broadleaf Herbicides
Ultim Total (Ultim + Disctinct + non-ionic surfactant + UAN)
Trade Name Ultim Distinct + non-ionic surfactant +liquid urea ammonium nitrate (UAN)
Active Ingredient
nicosulfuron/ rimsulfluron
diflufenzopyr/ dicamba+ non-ionic surfactant + urea ammonium nitrate
Formulation
(1:1) 75 DF
70 WG
Rate per hectare (active)
25 g/ha
0.2 kg/ha + 0.25% v/v + 1.25% v/v
Rate per hectare (product)
33 g/ha
0.285 kg/ha + 2.5 L/1,000 L + 12.5 L/1,000 L*
Rate per acre (product)
13 g/ac
0.115 kg/ac + 2.5 L/1,000 L + 12.5 L/1,000 L*

Precautions:

  • Apply to active growth stage of seedling broadleaf weeds (less than 5 cm tall).
  • Apply to annual grasses in the 1-6 leaf stage and to quackgrass in the 3-6 leaf stage
  • Ultim Total is available only as a co-pack of Ultim + Distinct.
  • Apply when temperatures above 4°C are predicted for the 24 hours before and after application.
  • Do NOT use on seed corn or sweet corn.*

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Label Expansions:

  • Accent 75DF is now registered for use on all sweet corn varieties, however not all varieties have been tested. Contact the variety manufacturer for more information on the tolerance of a specific variety to Accent 75DF
  • Peakplus is now registered for use on seed corn (see table below).

Postemergence Broadleaf Herbicides
Peakplus (Peak + Banvel II + non-ionic sufactant + UAN)
Trade Name
Banvel II + non-ionic surfactant
Active Ingredient
prosulfuron
dicamba + non-ionic surfactant
Formulation
75 DF
480 g/L
Rate per hectare (active)
10 g/ha
0.14 kg/ha + 0.22% v/v
Rate per hectare (product)
13.3 g/ha
0.3 L/ha + 2 L/1,000 L
Rate per acre (product)
5.3 g/ac
0.12 L/ac + 2 L/1,000 L

Precautions:

  • Apply when the corn is in the 2-7 leaf stage.
  • Controls most annual broadleaf weeds including triazine resistant lamb's-quarters and pigweed up to the 6-leaf stage; cocklebur and velvetleaf up to the 6-leaf stage; and ragweed up to the 8-leaf stage.
  • Do NOT apply to corn treated with organophosphorus insecticides.
  • Do NOT apply to popcorn or sweet corn.
  • Peakplus is a co-pack of Peak 75WG and Banvel II.

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Weed Control Rating Revisions:

The following weeds are registered for control or suppression using the following field corn herbicides. Refer to Table 9-1 and 9-2 in the 2006-2007 Guide for the appropriate control ratings of each product on the weed species identified below.

  • Burcumber - Pardner + atrazine. Rating: "8"
  • Sandbur - Accent. Rating: "7"
  • Field bindweed - Accent + Peakplus (Accent 1-Pass). Rating "5"

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Maximum Leaf Stage Revisions:

New information on maximum leaf stages that certain weeds are controlled by Callisto + atrazine.

Table 9-5. Maximum Weed Leaf Stages (or Height) for Postemergence Herbicide Applications in Corn
Annual Grass Weeds: Maximum Leaf Stage
Trade Name Application Window (corn leaf-over stage) Barnyard Grass Crabgrass Fall Panicum Green Foxtail Witch Grass Proso Millet
Callisto 3-8 leaf - - - - - -

All numbers expressed as leaf stages except as indicated.
- Indicates that either the weed in not controlled by this herbicide, or not enough data is available to specify a maximum leaf stage

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Annual Broadleaf Weeds: Maximum Leaf Stage

Trade Name Application Window (corn leaf-over stage) Wild buckwheat Cocklebur Jimsonweed Lady's-thumb Lamb's-quarters
Callisto 3-8 leaf 8 4 4 8

8
More...

Annual Broadleaf Weeds: Maximum Leaf Stage (con't)

Trade Name wild mustard Nightshade Pigweed Ragweed Velvetleaf
Callisto - 8 8 6
8

All numbers expressed as leaf stages except as indicated.
- Indicates that either the weed in not controlled by this herbicide, or not enough data is available to specify a maximum leaf stage

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Perennials: Maximum Leaf Stage

Trade Name Application Window (corn leaf-over stage) Quackgrass
Callisto 3-8 leaf -

All numbers expressed as leaf stages except as indicated.
- Indicates that either the weed in not controlled by this herbicide, or not enough data is available to specify a maximum leaf stage.

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Related Links

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For more information:
Toll Free: 1-877-424-1300
Local: (519) 826-4047
E-mail: ag.info.omafra@ontario.ca