Herbicide Recommendations for Soybeans: Postemergence Broadleaf Herbicides

Table of Contents

1. Basagran Forté
2. Blazer
3. Blazer + Assist
4. Classic + non-ionic surfactant
5. Firstrate + non-ionic surfactant + liquid fertilizer
6. Reflex + Agral 90 or Turbocharge
7. Pinnacle + non-ionic surfactant
8. Soybean Herbicide Weed Control Ratings (Table 11-1) (PDF file - 133 kb)
   • Annual Grasses
   • Broadleaf Weeds
   • Perennial Weeds
9. Other Soybean Weed Control Recommendations
   • Pre-Plant Burndown and Residual Control
   • Soil Applied Grass Herbicides
   • Soil Applied Broadleaf Herbicides
   • Soil Applied Grass and Broadleaf Herbicides
   • Soil Applied Tank-mix Options
   • Postemergence Grass Herbicides
   • Postemergence Grass and Broadleaf Herbicides
   • Postemergence Grass and Broadleaf Herbicides - Roundup Ready (glyphosate tolerant) varieties only
   • Postemergence Tank-mix Options
   • Spot Treatment
   • Wick Wiper and Roller Application
   • Preharvest
10. Stages of Soybean Leaf Development
11. Related Links

    Basagran Forté

    Trade Name	Basagran Forté
    Active Ingredient	bentazon
    Formulation	480 g/L
    Rate per hectare (active)	0.84 to 1.08 kg/ha
    Rate per hectare (product)	1.75 to 2.25 L/ha
    Rate per acre (product)	0.7 to 0.9 L/ac

Precautions

• Apply when soybeans are in unifoliate to 4th trifoliate leaf stage and when weeds are small and actively growing.
• Temporary crop injury may occur under abnormally hot, humid conditions.
• Cool weather or drought may delay control.
• For improved and more consistent control of velvetleaf and lamb's-quarters, 10 L/ha of 28% urea ammonium nitrate (UAN) or 6 L/ha of liquid ammonium sulphate may be added. The addition of either nitrogen source may cause slight leaf burn, but new growth is normal and crop vigour is not reduced.
• Use the higher rate of Basagran Forté when weed pressure is high, weeds are large or conditions for activity are unfavourable.

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Precautions

• Apply to emerged weeds up to 10 cm in height (refer to labels for weed heights) when soybeans are in the 1-3 trifoliate leaf stage.
• Do NOT apply before the first trifoliate leaf stage of the soybeans.
• Good spray coverage on the weeds is important for good weed control.
• Soybeans may exhibit speckling, bronzing and/or leaf burn. The trifoliate leaf emerging at the time of application may be distorted. Soybeans usually outgrow these conditions and continue to grow at a normal rate with no adverse effect on vigour, maturity, or crop yield.
• Do NOT apply Blazer to soybeans that have been subjected to stress (see product label).
• Do NOT add oils or surfactants to applications of Blazer at 2.5 L/ha alone.

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Precautions

• Apply to emerged redroot pigweed up to and including the 4-leaf stage and to common ragweed up to and including the 8-leaf stage when soybeans are in the 1-3 trifoliate leaf stage.
• Do NOT apply before the first trifoliate leaf stage of the soybeans.
• Good spray coverage on the weeds is important for good weed control.
• Soybeans may exhibit speckling, bronzing and/or leaf burn. The trifoliate leaf emerging at the time of application may be distorted. Soybeans usually outgrow these conditions and continue to grow at a normal rate with no adverse affects on vigour, maturity or crop yield.

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Precautions

• Do NOT use on soils with pH > 7.8.
• Optimal timing for broadleaf control is when the soybeans are in the 1-3 trifoliate stage of growth.
• Do NOT apply before the first trifoliate is fully expanded or after the initiation of flowering.
• Addition of 28% UAN is recommended for improved control of velvetleaf.

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Precautions

• Apply up to the 8-leaf stage for common ragweed and cocklebur, 6-leaf stage for giant ragweed, and 4-leaf stage for velvetleaf.
• Apply any time prior to flowering stage of soybeans.
• Application prior to full emergence of first trifoliate may cause temporary yellowing of soybeans.

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Precautions

• Apply early postemergence at 1-2 trifoliate to crop when weeds are small and actively growing (2-4 leaf stage).
• Use 200-350 L/ha (80-140 L/ac) water. Use higher rates of water and pressure for a heavy weed or crop canopy.
• Some bronzing may occur to soybean leaves at the time of application, but plants outgrow these effects without harming maturity or yield.
• Do NOT apply Reflex to any field more often than once every 2 years.
• Do NOT apply to soybeans und

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  er stress.
• Some rotational cropping restrictions apply (Table 4-3 (PDF - 80K) and Table 4-4 (PDF - 82K).

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Precautions

• Apply to emerged weeds up to 10 cm in height when soybeans have the first trifoliate leaf fully expanded.
• Do NOT apply to soybeans, which have initiated flowering.
• The higher rate should be used for lamb's-quarters and velvetleaf.
• The addition of UAN (28-0-0) at 4% v/v will enhance the control of velvetleaf.

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Related Links

• Weeds in Ontario
• Soybeans in Ontario
• Problem Weed Control in Field Crops
• Pesticide Application and Safety
• Pesticide Companies and Agents
• OMAFRA Sprayer Calibration Calculator
• Search the PMRA website
• OMAFRA Publication 505: Ontario Weeds
• OMAFRA Publication 75: Guide To Weed Control

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