Table 2.4-12. Postemergence herbicides for soybean
See specific product label to determine correct rate for the weed species found in individual fields.
General information:
- Good growing conditions are necessary to achieve good weed control from postemergence herbicide applications.
- Weed growth stage is important for control. Soybean growth stage is also important for some treatments.
- A surfactant, crop oil concentrate, and/or fertilizer solution may be needed for some treatments or some weed species.
| Herbicide | Product/A | lb ai/A | Remarks |
|---|---|---|---|
| Assure ll 0.88E/Targa (quizalofop) | 5–10 fl oz | 0.03–0.06 | Always include a crop oil concentrate or surfactant in the spray solution (Table 2.4-14). Do not use crop oils manufactured from vegetable oils. When tank-mixing with a broadleaf herbicide, always read both labels to make sure the right surfactant and concentration are used. Apply when grasses are within the recommended growth stage specified on the label (7 fl oz for foxtails and panicum). Perennial grasses may require a second application for complete control. Assure II/Targa must be applied at least 80 days before harvest. |
| Basagran 4S (bentazon) | 1.5–20 pt | 0.75–1.0 | Application should be made while weeds are small and actively growing and before weeds reach maximum size listed on product label. Add crop oil concentrate or nitrogen solution to spray mixture as directed (Table 2.4-14). Apply in a minimum of 20 gal of water/A and at minimum pressure of 40 psi. Tank-mixing with Blazer improves pigweed control. See mixtures portion of this table for prepackaged mixes containing Basagran and Blazer. (Water quality advisory) |
| Blazer 2S or Ultra Blazer 2S (acifluorfen) | 0.5–1.5 pt | 0.125–0.38 | Application should be made when weeds are small and actively growing and before weeds reach maximum size listed on product label. Soybeans should have at least one to two trifoliate leaves. Apply in a minimum of 20 gal of water/A and at a minimum pressure of 40 psi. Do not apply when weeds or crop are under stress. Tank-mixing with Basagran improves velvetleaf control. See the mixtures portion of this table for pre-packaged mixes containing Blazer and Basagran. Blazer must be applied at least 50 days before harvest. (Water quality advisory) |
| Cadet 0.91EC (fluthiacet) | 0.4–0.9 fl oz | 0.0028–0.006 oz | Application timing to soybeans is from 1st trifoliate to full flowering. Apply 0.4 to 0.6 fl oz/A with glyphosate (RR-soybean) or glufosinate (LL-soybean) or 0.6 to 0.9 fl oz when applied alone. Include the necessary spray additives (NIS or COC plus AMS or nitrogen solution). Applications should be made when susceptible broadleaf weeds are small. Cadet is very effective on velvetleaf, but other broadleaf weeds must be small to achieve control/suppression. Cadet does not provide residual weed control. Cadet can cause bronzing or browning of the soybean leaves. (Cadet is similar to Aim and can be used preplant/preemergence to assist in a burndown program) |
| Classic 25DF (chlorimuron) | 0.5–0.75 oz | 0.125–0.187 oz | Application should be made while weeds are small and actively growing. Soybeans should have at least one trifoliate leaf. Always read the label to determine the proper surfactant to use with this material (Table 2.4-14). If the soil pH is greater than 7.0, at Classic rates of 0.5 oz/A or greater, do not plant corn for at least 9 months after application. Classic must be applied at least 60 days before harvest. See Table 2.4-15 for additional recrop restrictions. See "Herbicide Resistance Management" in Part 2, Section 1 for more information. |
| Cobra 2E (lactofen) | 6.0–12.5 fl oz | 0.09–0.19 | Applications should be made while weeds are small and actively growing. Soybeans should have one to two trifoliate leaves. Use surfactant or crop oil concentrate as directed (Table 2.4-14). May cause foliar injury to soybeans. Use 6–8 fl oz/A for control of four- to six-leaf common ragweed or pigweed. Cobra also may be used at a reduced rate in combination with other broadleaf herbicides. Apply at least 45 days before harvest. See a Cobra label for additional information. |
| FirstRate 84WDG (cloransulam) | 0.3–0.6 oz | 0.25–0.5 oz | Application can be made from first soybean trifoliate leaf through 50% flowering stage and when weeds are young and actively growing. Always include proper adjuvant in spray tank. Tank-mix to broaden weed spectrum. FirstRate may be applied up to 0.6 oz for heavy weed infestations or added residual control. Do not harvest soybeans for grain until 65 days after application. (Water quality advisory) |
| Fusilade DX 2E (fluazifop) | 6–12 fl oz | 0.09–0.18 | Add surfactant or crop oil concentrate to spray solution as directed (Table 2.4-14). See label for rate and size of weed to be controlled (12 fl oz for foxtails, panicum, and crabgrass). Most annual grasses should be treated when 2–4 inches in height. Perennial grasses may require second application to achieve complete control. Tank-mixes may reduce grass control; follow label recommendations to overcome antagonism. |
| Glyphosate | See Table 2.4-1a | Apply over-the-top to Roundup Ready soybean varieties only. Various glyphosate products are available; see Table 2.4-1a for some common products and rates. See comments under Roundup Weather Max for additional information about in-crop use. Depending on which glyphosate product is used, select appropriate rate and include proper adjuvant, if necessary. | |
| Harmony SG 50DF (thifensulfuron) | 0.125 oz (1/8 oz) | 0.063 oz | Harmony SG is a very concentrated formulation. Be sure to use proper application rate otherwise soybean injury may occur. Add surfactant and/or fertilizer solution as directed (Table 2.4-14). Apply when weeds are actively growing and before they reach maximum size listed on product label. Soybeans should have a minimum of one trifoliate leaf. Any crop may be planted within 45 days following Harmony SG application. Adding Classic increases control spectrum, but rotational restrictions for Classic must be followed. Harmony SG must be applied at least 60 days before harvest. See “Herbicide Resistance Management” in Part 2, Section 1 for more information. |
| Liberty 280 2.34L (glufosinate) | 22–29 fl oz | 0.40–0.53 | Apply over-the-top to glufosinate-resistant soybean varieties (e.g., LibertyLink) only. Treat from soybean emergence to the bloom stage. For best results, plant in narrow rows and apply 22 to 29 fl oz Liberty about a month after planting when weeds are 2–6 inches tall. If using sequential applications, apply 10–14 days apart and do not apply more than 65 fl oz/A/season and before soybean bloom stage. A residual soil-applied product or a sequential post application may be necessary depending on weed species and severity. Liberty provides no soil residual activity. Tank-mixing Liberty with other herbicides including residual products (e.g., Dual, Prefix, Warrant) is allowed. Local university research has not observed increased injury with most herbicide combinations; some stunting and leaf burn was observed when Liberty was tank-mixed with Prefix. See Table 2.4-14 for adjuvant information. Liberty must be applied at least 70 days before harvest. |
| Poast Plus 1E or Poast 1.5E (sethoxydim) |
18–36 fl oz or 0.75–1.5 pt |
0.14–0.28 | Poast Plus contains some surfactant. Always include crop oil concentrate or Dash to spray solution as directed (Table 2.4-14). Nitrogen fertilizer additives may improve control of some species. Application should be made when grasses are actively growing and within the recommended stage of growth on the Poast Plus/Poast label (24 fl oz Poast Plus or 1 pt Poast for foxtails, panicum, and crabgrass). Perennial grasses may require a second application to achieve control. Tank-mixes may reduce grass control; follow label recommendations to overcome antagonism. Poast Plus/Poast must be applied at least 75 days before harvest. |
| Pursuit 2S or 70 DG (imazethapyr) |
4 fl oz or 1.44 oz |
0.063 | Add a nonionic surfactant and fertilizer solution as directed (Table 2.4-14). Apply when weeds are actively growing and before they reach the maximum size listed on product label. Follow labeled rotational crop restrictions (Table 2.4-15). Pursuit must be applied at least 85 days before harvest. See “Herbicide Resistance Management” in Part 2, Section 1 for more information. (Water quality advisory) |
| Raptor 1S (imazamox) | 4–5 fl oz | 0.5–0.625 oz | Apply when weeds are actively growing and before they reach the maximum size listed on product label. Add a nonionic surfactant and fertilizer solution as directed (Table 2.4-14). Less persistent than Pursuit or Scepter, but follow labeled rotational crop restrictions (Table 2.4-15). Raptor must be applied at least 85 days before harvest. See “Herbicide Resistance Management” in Part 2, Section 1 for more information. |
| Reflex 2E or Flexstar 1.88E (fomesafen) |
1.0–1.5 pt or 1–1.5 pt |
0.25–0.375 or 0.235–0.35 |
Apply to actively growing weeds. Use surfactant, crop oil concentrate, and/or fertilizer as directed (Table 2.4-14). Reflex or Flexstar must be applied prior to bloom. Follow labeled rotation restrictions (Table 2.4-15). (Water quality advisory) Flexstar GT is a premix of glyphosate (Touchdown) + fomesafen (Flexstar) for use in Roundup Ready soybeans to control broadleaves and grasses. See label for additional details. |
| Resource 0.86 EC (flumiclorac) | 4–12 fl oz | 0.027–0.08 | Apply to actively growing weeds at growth stages recommended on the label. Apply in a minimum of 10 gal of /A and a minimum pressure of 30 psi. In most cases, use a crop oil concentrate or other additive according to produce label. Tank-mixing broadens the weed-control spectrum. |
| Roundup WeatherMax 4.5S or PowerMax (glyphosate) | 11–44 oz | 0.375–1.5 ae | Apply over-the-top to Roundup Ready soybean varieties only. (Note: Various glyphosate products are available; some may be used for in-crop applications in Roundup Ready soybean varieties. See Table 2.4-1a for other glyphosate products. Refer to current product label for active ingredient concentration, application rate, and other use restrictions.) Treat in-crop from soybean emergence throughout flowering stage in 5–20 GPA. For best results, plant in narrow rows and apply 22 fl oz/A Roundup WM about a month after planting when weeds are 4–8 inches tall. (Sequential applications may be necessary if new weed growth occurs. Apply 11 fl oz for weeds 1 to 3 inches tall, 16 fl oz for 3- to 6-inch weeds, and 22 fl oz for 6- to 12-inch-tall weeds). For perennial weeds, apply 22–44 fl oz/A when weeds are at least 6 inches tall; a sequential treatment may be necessary. Do not apply more than 44 fl oz/A Roundup WM at any single application. Do not apply more than 66 fl oz/A Roundup WM in-crop. Preharvest applications are allowed on all soybean varieties as a harvest aid. See section below for more details. Do not graze or feed crop within 14 days of last application. |
| Scepter 1.5S or 70DG (imazaquin) |
0.66 pt or 2.8 oz |
0.125 | Add nonionic surfactant to spray solution (Table 2.4-14). Apply to actively growing weeds before they reach 12 inches tall. Do not plant corn for at least 9.5 months following application. Follow labeled rotational crop restrictions (Table 2.4-15). Do not use Scepter if chlorimuron products were used earlier in the year. Scepter must be applied at least 90 days before harvest. See “Herbicide Resistance Management” in Part 2, Section 1 for more information. (Water quality advisory) |
| Select 2E or Select Max 0.97EC (clethodim) |
6–16 fl oz or 6–32 fl oz |
0.094–0.25 or 0.05–0.25 |
Apply to actively growing grasses at the weed height recommended on the Select label (2–6 inches for most annuals). The lowest rate is for early application on certain grasses (6–8 fl oz for foxtails, panicum, and crabgrass). Always include crop oil concentrate at 1 qt/A. Add ammonium sulfate at 2.5 lb/A to improve quackgrass control. Select must be applied at least 60 days before harvest. Clethodim may also be available as Select Max 0.97E. Select Max contains a specialized adjuvant system, thus nonionic surfactant plus AMS is the standard adjuvant recommendation. Also, Select Max does not require additional adjuvants (other than AMS) when tank-mixed with a “loaded” glyphosate product and provides greater flexibility in additive selection when tank-mixed with other products. |
| Touchdown Total 4S (glyphosate) | 24–48 fl oz | 0.75–1.5 ae | Apply over-the-top to glyphosate-tolerant (Roundup Ready) soybean varieties only. Treat in crop from soybean emergence through full flowering of soybeans. For best results, plant in narrow rows and apply 24 fl oz/A Touchdown within 30 days after planting on weeds up to 6 inches tall. Repeat applications may be required if new weed growth occurs. Perennial weeds may require higher rates and repeat applications. Best control may be obtained when perennial weeds are treated in the bud to bloom growth stage. Include ammonium sulfate in the tank to improve control of weeds (Table 2.4-14). Do not apply more than 48 fl oz/A in any single application. Touchdown may be used in combination with many residual and post herbicides. Do not graze or harvest soybean for forage or hay. Touchdown may be used as a harvest aid on all soybean varieties. See section below for more details. |
| Warrant 3CS (acetochlor) | 1.25–2.0 qt | 0.94–1.5 | Warrant is designed to be applied postemergence with glyphosate in Roundup Ready soybean systems or other herbicides to provide residual weed control of several annual grasses and broadleaf weeds. This tank-mix may be applied from soybean emergence to R2 stage; but best results will be obtained when it is applied from V2-V3 soybean stage and weeds are less than 4 inches tall. The typical use rate of Warrant is 1.5 qt/A when it is tank-mixed. Warrant will not control emerged weeds. (Water quality advisory) |
| Mixtures | |||
| Extreme 2.17L (imazethapyr + glyphosate) | 3 pt | 0.81 | Apply over-the-top to Roundup Ready soybean varieties only. to weeds 1–8 inches tall. Include necessary adjuvant in the spray solution (Table 2.4-14). Apply at least 85 days before harvest. See Table 2.4-15 for recropping restrictions. (Water quality advisory) |
Flexstar GT3.5 2.82EC (fomesafen + glyphosate) |
3.5 pt |
1.2 |
Apply over-the-top to Roundup Ready soybean varieties only. Apply to weeds 1–6 inches tall. Typically AMS or UAN can be added to the spray solution, but other adjuvants may be include under adverse conditions (see label for details). Apply at least 45 days before harvest. See Table 2.4-15 for recropping restrictions. (Water quality advisory) |
| Fusion 2.56E (fluazifop + fenoxaprop) | 6–10 fl oz | 0.125–0.2 | Always include crop oil concentrate or nonionic surfactant with the spray solution (Table 2.4-14). Nitrogen fertilizer additives also may be included. See a Fusion label regarding tank-mixes and sequential applications (8 fl oz for foxtails, panicum, and crabgrass). Fusion must be applied prior to bloom. |
Permit Plus 74 WDG (halosulfuron + thifensulfuron) |
0.75 oz |
0.035 |
Permit Plus is labeled only for soybeans designated as “sulfonylurea-tolerant soybeans” (STS). Permit Plus can be applied from V1 stage up till 88 days before harvest. Permit Plus will not control grass species. Add nonionic surfactant or crop oil unless tank-mix partners restrict them. Addition of ammonium sulfate (AMS) or liquid nitrogen is also recommended. This product can be tank-mixed with glyphosate for soybeans with stacked traits of STS and Roundup Ready. See “Herbicide Resistance Management” in Part 2, Section 1 for more information. |
| Prefix 5.3E (s-metolachlor + fomesafen) | 2–2.33 pt | 1.33–1.54 | Prefix may be applied as a post application from cracking through the third trifoliate stage. Prefix will only suppress or not control emerged weeds. Tank-mix with glyphosate (in RR soybeans) or other herbicides to control emerged weeds. Add nonionic surfactant (1 qt/100 gal) to spray solution. Do not include crop oil concentrate when applying Prefix post. Some temporary crop injury may occur following a post Prefix treatment. For residual weed control activity, rainfall must occur within 7–10 days after application. Make application at least 90 days before harvest. Do not graze or feed treated soybeans to livestock. |
| Storm 4S (acifluorfen + bentazon) | 1.5 pt | 0.75 | At 1.5 pt/A, Storm is equivalent to mixing 1 pt of Basagran plus 1 pt of Blazer. See Table 2.4-14 or a label for adjuvant specifics. Storm is better suited for pigweed and annual morningglory problems than Galaxy. Storm must be applied at least 50 days before harvest. (Water quality advisory) |
| Synchrony XP 28.4WDG (chlorimuron + thifensulfuron) | 0.375–1.125 oz | 0.10–0.32 oz | Synchrony XP may be applied postemergence to STS soybeans at a use rate of 0.375–1.125 oz/A; and to non-STS soybeans at 0.375 oz/A. Apply after first soybean trifoliate has fully expanded and no later than 60 days before harvest. Always include the necessary adjuvants. Synchrony XP may be tank-mixed to improve weed control spectrum. Refer to label for additional use directions and restrictions. Synchrony XP can also be applied as a fall application and as a burndown/PRE in the spring. See Table 2.4-15 for recropping restrictions. See “Herbicide Resistance Management” in Part 2, Section 1 for more information. |
| Harvest Aid Applications | |||
Aim 2EC (carfentrazone) |
2 fl oz |
0.031 |
Use as a harvest aid to desiccate certain broadleaf weeds. Application shall be made when the crop is mature and the grain has begun to dry down. Apply in 10 gal/A water. Include necessary adjuvants and make sure spray coverage is sufficient, otherwise poor control will result. |
| Clarity 4S (dicamba) | 8–64 fl oz | 0.25–2.0 | Apply Clarity to actively growing weeds after soybean pods have reached mature brown color and at least 75% leaf drop has occurred. A waiting interval of 14 days is required before harvest. Do not feed soybean fodder or hay following a preharvest applicat |
| Glyphosate | See Table 2.4-1a | Up to 0.75 | Apply glyphosate to soybeans after pods have set and lost all green color (80–90% drop of leaves has occurred). Apply glyphosate in 10–20 gallons of water/A to control weeds that may interfere with harvest or to control perennials such as quackgrass or Canada thistle. Allow a minimum of 7 days between application and harvest. Do not graze or harvest the treated crop for livestock feed within 25 days of application. Do not use on soybeans grown for seed. |
| Gramoxone SL 2S (paraquat) | 8–16 fl oz | 0.125–0.25 | Gramoxone may be used for drying certain weeds and quickening berrydrop of Eastern black nightshade just before soybean harvest. Soybean plants must be mature (65% or more of the seed pods have reached mature brown color or seed moisture is 30% or less). Apply Gramoxone at 8–16 fl oz/A and include nonionic surfactant at 1 qt/100 gallons of spray. Do not apply within 15 days of harvest. Do not graze or harvest for the forage or hay. |
