SOYBEAN WEED MANAGEMENT GUIDE 38

Transcription

1 SOYBEAN WEED MANAGEMENT GUIDE 38 TABLE 22: COMMENTS FOR THE RESPECTIVE HERBICIDES s arranged alphabetically by within timing of application (pre-plant, soil-applied, or postemergence) with rate and remarks concerning their use. PPI= pre-plant incorporated PRE= preemergence POST= postemergence 2,4-D 2,4-D 4L formulations ** many s Banvel 4S Clarity 4S Sterling 4S or other available formulations Canopy EX 29.5DG dicamba chlorimuron + tribenuron paraquat Gramoxone Inteon 2L ** PREPLANT lb Add 2,4-D to paraquat or glyphosate for added burndown of hard to control broadleaf weeds. Apply 7 to 30 days pt prior to planting, depending on rate and formulation (ester or amine). Refer to Table 1. Use 2,4-D for added control or suppression of mustard spp., plantains, horseweed, and 2,4-D susceptible annual broadleaf weeds. PREPLANT lb Add dicamba to paraquat or glyphosate for added burndown of hard to control broadleaf weeds, particularly oz marestail (horseweed). Apply Banvel or Sterling 30 days oz prior to planting. Following Clarity applications, a oz minimum accumulation of one inch of rainfall or overhead irrigation followed by a 14 day waiting period for the 4 to 8 oz/a rates or a 28 day waiting period for the 16 oz/a rate is required (refer to Table 1). Dicamba is an excellent alternative for glyphosate-resistant horseweed. PREPLANT lb lb PREPLANT oz lb pt Apply with glyphosate or Gramoxone to no-till fields, or alone to clean conventional-tillage fields anytime after harvest at 2.2 to 3.3 oz/a up to 14 days before soybean planting, or 1.1 to 2.2 oz/a up to 7 days before soybean planting; consult label for details. For best results apply to annual weeds less than 3 inches in height or diameter and perennial weeds less than 6 inches in height or diameter. The addition of 1 pint/a of 2,4-D ester is recommended, and is required for some species. s must include either a crop oil concentrate or a nonionic surfactant. Crop oil concentrate is the required adjuvant unless tank-mixing with a product that precludes its use. On soils with ph 7.0 or less, Canopy EX can be applied at rates of oz/a., and will provide residual control or suppression of several winter and summer annual weeds through normal planting dates, but will not provide season-long control. Restricted Use Pesticide. Apply in 20 to 60 gallons of water per acre. Rate is dependent on weed size (see label). Paraquat may not control weeds taller than 6 inches. Increase gallonage as density of stubble, crop residue or weeds increases. 2,4-D at pint per acre may be added to this program for additional control of marestail (horseweed), common lambsquarters, common ragweed, and other emerged, susceptible broadleaf weeds.

2 SOYBEAN WEED MANAGEMENT GUIDE 39 glyphosate ae formulations Roundup Original Max 4.5L ** Roundup PowerMAX or WeatherMax 4.5 L ** Touchdown HiTech 5SL ** Touchdown Total 4.17 SL ** or other available formulations PREPLANT lb ae Glyphosate is effective in heavy annual weed infestations and with large weeds where thorough coverage with pt paraquat is not possible. Higher rates will control perennial species, but those species often are not pt present or susceptible at the time of planting. Use rates vary by product, formulation, and weed size. Higher rates pt are usually recommended for annual weeds taller than 6 inches. Horseweed taller than 6 inches may not be pt controlled. s with fan-type nozzles generally have been more effective than with flood nozzles. Use 10 to 40 gallons of water per acre. To aid in the control of marestail/horseweed, common lambsquarters, common ragweed, and other emerged, susceptible broadleaf weeds, 2,4-D or dicamba may be added. Glyphosate is available in some pre-packaged mixtures, but glyphosate rate may not be adequate for burndown control.

3 SOYBEAN WEED MANAGEMENT GUIDE 40 Soil-applied s: sulfentrazone Authority 75DF Authority First 70DF Authority MTZ 45DF Sonic 70DF chlorimuron + metribuzin Canopy 75DF Command 3ME Define 4SC clomazone flufenacet s-metolachlor Dual Magnum 7.62E Dual II Magnum 7.64E Boundary 6.5EC Prefix 5.3E Sequence 5.25EW lb PRE oz oz oz oz lb lb 4-7 oz lb pts lb oz lb pt pt pt pt pt Soybean stunting may occur if excessive rainfall occurs after application but before soybeans emerge. Do not apply if there are visible signs of cracking due to soybean emergence, or serious crop injury may result. Observe labeled rotational crop restrictions for all products containing sulfentrazone. Authority First and Sonic are premixes of Authority and FirstRate. Authority MTZ is a premix of Authority and Sencor. Apply prior to soybean emergence. Do not use on sand or any soil with less than 0.5% om. Do not apply more than 2.25 oz/a if soil ph is 7.0 or higher. Observe rotational crop restrictions. Use of STS soybeans may allow application of higher Canopy rates with reduced risk of crop injury. Mechanical incorporation will improve weed control when no rainfall or irrigation occurs within 10 to 14 days after planting. Apply to the soil and uniformly incorporate into the top 2 inches within 14 days before planting using a disk, harrow, rolling cultivator, or similar implement. Observe labeled rotational crop restrictions for all products containing chlorimuron (Classic). Command 3 ME formulation is labeled for PRE application only. Clomazone is very prone to offsite movement due to volatility. Refer to label for precautions. Do not apply during temperature inversions or when wind speed is greater than 10 mph. Apply in a minimum spray volume of 10 gal/a. Use coarse sprays to reduce drift. Do not apply Command 3ME within 1,200 feet of areas listed on label including towns, subdivisions and commercial fruit and vegetable production. Observe labeled rotational crop restrictions. Preplant surface and preplant incorporated applications may be applied up to 14 days before planting. The 14 oz/a use rate will provide full-season control of annual grasses on coarse-textured soils, but will provide only early-season control on medium and fine textured soils. Rates lower than 14 oz/a will provide only early-season weed control on all soil textures. Mechanical incorporation will improve weed control when no rainfall or irrigation occurs within 10 to 14 days after planting. Apply to the soil and uniformly incorporate into the top 2 inches within 14 days before planting using a disk, harrow, rolling cultivator, or similar implement. An incorporated application will improve yellow nutsedge control. For surface applications: if adequate soil moisture is not received within 7 to 10 days after application, use of a rotary hoe or shallow cultivation is recommended. ## Refer to TABLE 7: USE RATE PER ACRE FOR SOIL-APPLIED HERBICIDES

4 SOYBEAN WEED MANAGEMENT GUIDE 41 cloransulam FirstRate 84WG Gangster Multi-Pack Authority First 70DF Sonic 70DF Lorox 4L linuron alachlor Micro-Tech 4L or other available formulations Outlook 6.0 EC dimethenamid dimethenamid-p pendimethalin Prowl 3.3EC Prowl H2O 3.8AS or other formulations flumetsulam Python 80WDG fomesafen Reflex 2LC Prefix 5.3E lb PRE oz oz oz oz lb pt lb qt lb lb 8-21 oz lb pt pt lb oz 0.25 lb 1.0 pt pt FirstRate water-dispersible packets are not soluble in liquid fertilizer solutions; premixing in water is required. A pre-packaged mixture of FirstRate and Valor SX is available as Gangster. Gangster can be applied as a fall (after October 15) or spring preplant treatment or preemergence. See Valor SX entry for additional comments. Authority First and Sonic are premixes of Authority and FirstRate. Authority MTZ is a premix of Authority and Sencor. Provide good agitation in tank before and during application. Follow labeled directions regarding soybean planting depth. Do not use on sand or loamy sand soils or any soil with less than 1% OM. Do not plant any crop not on label within 4 months of application. Restricted Use Pesticide. Mechanical incorporation will improve weed control when no rainfall or irrigation occurs within 10 to 14 days after planting. Apply to the soil and uniformly incorporate into the top 2 inches within 14 days before planting using a disk, harrow, rolling cultivator, or similar implement. For surface applications: if adequate soil moisture is not received within 7 to 10 days after application, use of a rotary hoe or shallow cultivation is recommended. Alachlor is not recommended for incorporation on coarse soils in the Southeast. Do not exceed a rate of 12 oz/a of Outlook on coarse soils with less than 1.5% organic matter. PPI applications are not recommended on these soils. Mechanical incorporation will improve weed control when no rainfall or irrigation occurs within 10 to 14 days after planting. Apply to the soil and uniformly incorporate into the top 2 inches within 14 days before planting using a disk, harrow, rolling cultivator, or similar implement. For surface applications: if adequate soil moisture is not received within 7 to 10 days after application, use of a rotary hoe or shallow cultivation is recommended. Adjust rate to soil texture. Under certain environmental conditions, a PRE application can result in brittle soybean stems. If incorporating, do so to a depth of 2 inches. Rainfall or irrigation is need to activate Python. Observe rotational restrictions for products containing flumetsulam. Reflex is labeled for preemergence use as part of a planned two-pass system. Reflex as a soil-applied herbicide will control or suppress certain broadleaf weeds if rainfall occurs shortly after application. Small-seed broadleaves are most susceptible to Reflex as a soilapplied herbicide. Prefix followed by sequential applications of Reflex are prohibited. ## Refer to TABLE 7: USE RATE PER ACRE FOR SOIL-APPLIED HERBICIDES

5 SOYBEAN WEED MANAGEMENT GUIDE 42 imazaquin Scepter 70DG Sencor 75 DF Sencor 4L metribuzin es Authority MTZ 45DF Boundary 6.5EC Canopy 75DF chlorimuron + thifensulfuron Synchrony XP 28.4XP trifluralin Treflan 4EC or other formulations lb Injury in the form of stunting and leaf discoloration may occur with some soybean varieties under certain adverse 2.8 oz weather conditions. Performance is more consistent when Scepter is applied PPI vs PRE. Observe labeled rotational crop restrictions for products with imazaquin lb Plant at least 1.5 inches deep. Do not use on sand, sandy loam or soils with less than 0.5% organic matter. If lb used on coarse textured soils with less than 2% organic pt matter or if heavy rainfall follows soon after application, severe stand losses can occur. Certain organophosphate soil insecticides placed in contact with seed also may oz result in increased soybean injury from metribuzin. Do not pt use on Altona, Coker 102 or 156, Gervin, Semmes, Tracy 4-6 oz or Varosy varieties. The lowest rates have not effectively controlled cocklebur, jimsonweed or morningglory. Rainfall ( inch) within 2 weeks after application is required to activate herbicide. Do not replant treated areas to any crop other than soybeans within 4 months after treatment. Read and follow the label for such use. PRE PPI lb lb 0.75 to 3 oz lb pt pt Although the rate range for preemergence control ranges from 0.75 to 3 oz/a, limited residual control should be expected with rates less than 2 oz/a. Synchrony XP has limited burndown activity on many common weed species found in no-till fields and typically needs to be tank-mixed with another burndown herbicide. Rotational crop intervals vary for different rates and soil ph; refer to supplemental label for restrictions. Incorporate within 24 hours after application. Plant soybeans after early season adverse weather has passed. Do not plant deeper than 2 inches. Follow label for proper soil incorporation procedures. ## Refer to TABLE 7: USE RATE PER ACRE FOR SOIL-APPLIED HERBICIDES

6 SOYBEAN WEED MANAGEMENT GUIDE 43 flumioxazin Valor SX 51WDG Gangster Multi-Pack Valor XLT 40 WDG flumioxazin + chlorimuron Valor XLT 40 WDG PRE lb oz oz oz PRE oz/a Do not mechanically incorporate Valor into the soil after application. Valor has some burndown activity, but it should be tank-mixed with glyphosate or paraquat in most cases. Rate is dependent upon weed species targeted, soil type, and soil organic matter; refer to label. Valor SX or Gangster tank-mixed with alachlor (Lasso, MicroTech), flufenacet (Define), metolachlor (Dual, Boundary) or dimethenamid (Outlook) must be applied a minimum of 14 days prior to planting. Or, Valor SX or Gangster may be applied 14 days prior to planting followed by one of these products applied at planting. These tank-mixes are currently not allowed with Valor XLT. Do not apply products containing Valor if beans have begun to emerge. Splashing soil from irrigation or heavy rainfall may cause injury to newly emerged soybeans. Gangster is a pre-packaged mixture of Valor and FirstRate. Valor XLT is a premix of Valor and Classic. Either can be applied as a fall (Gangster after October 15, Valor XLT after November 15) or spring preplant treatment or preemergence. Products containing flumioxazin have specific tank-cleaning instructions on the label or in technical bulletins to help avoid contaminant injury from spray tank residues. Do not mechanically incorporate Valor XLT into the soil after application. One of the s in Valor XLT (chlorimuron) is a group 2 herbicide, and there is currently no known resistance to group 2 herbicides. Valor XLT has some burndown activity, but it should be tank-mixed with glyphosate or paraquat in most cases. A rate range of up to 5 oz/a, dependent upon weed species, is included on the label. However, only 3 oz/a/season is allowed in DE and NJ; refer to label. Valor XLT can be tank-mixed with products such as Command or pendimethalin for improved grass control. Do not tank-mix Valor XLT with alachlor (Lasso, MicroTech), flufenacet (Define), metolachlor (Dual, Boundary) or dimethenamid (Outlook). Do not apply Valor XLT if beans have begun to emerge. Splashing soil from irrigation or heavy rainfall may cause injury to newly emerged soybeans. Valor XLT can be applied as a fall (after November 15) or spring preplant treatment or preemergence. Products containing flumioxazin have specific tank-cleaning instructions on the label or in technical bulletins to help avoid contaminant injury from spray tank residues. ## Refer to TABLE 7: USE RATE PER ACRE FOR SOIL-APPLIED HERBICIDES

7 SOYBEAN WEED MANAGEMENT GUIDE 44 Postemergence Broadleaf s: Rate Remarks Active ingredient 2,4-DB lb Butyrac 200 2L many formulations available Basagran 4L ** es Storm 4S ** Blazer 2L** Ultra Blazer 2L ** es Storm 4S ** Classic 25WG ** bentazon acifluorfen chlorimuron Synchrony XP 28.4XP ** Cobra 2EC ** lactofen pt lb qt 1.5 pt lb pt pt 1.5 pt lb oz oz 0.20 lb 12.5 oz 2,4-DB is not recommended for use by itself due to limited control and potential for crop injury. Rather 2 oz of 2,4-DB can improve morningglory, cocklebur, and jimsonweed control when tank-mixed with other postemergence herbicides. Potential for crop injury is increased under hot, dry growing conditions. If more than 2 oz/a rate is used, apply as directed spray into rows when soybeans are 8 to 12 inches high and cocklebur, morningglory, jimsonweed and pigweed have not exceeded a height of 3 inches. Top of weed seedling must be sprayed. Use precision directed spray application equipment. Apply with sprayer nozzles mounted on skids or gauge wheels. Do not spray more than one-third of the base of soybean as severe injury may occur. Apply to weeds when they are small and actively growing. Weed growth stages generally correspond to soybean growth stages of one- to two-trifoliate leaves. Yellow nutsedge may be controlled best when the application is followed in 7 to 10 days with a repeated application or by cultivation in 10 to 14 days. Soybeans may exhibit a slight yellowing, bronzing or speckled appearance, which generally is soon outgrown. Do not apply to soybeans growing under unfavorable conditions and exhibiting stress symptoms. Apply when weeds are 2 to 4 inches high and actively growing and when soybeans are in the one- to two-trifoliate leaf stage. Do not apply when crop and weeds are under stress. Apply with 10 to 50 gallons of spray volume per acre, and a minimum of 40 to 60 pounds per square inch. Addition of surfactant to the 2L formulation may improve control on drought-stressed or slightly oversized weeds; but applications made under these conditions generally will be less satisfactory than those made under optimum conditions. Apply to young, actively growing weeds within labeled weed growth stages. Classic label states that the first trifoliate leaf of the soybean is fully expanded before the application is made. Apply with a minimum of 10 gallons per acre. Floodtype, low-pressure nozzles are not recommended. Use of STS varieties will reduce the risk of injury. Synchrony XP can be applied to non-sts soybean varieties at oz/a use rate or to STS varieties only at the 0.75 oz/a rate. Observe labeled rotational crop restrictions for all products containing Classic. Cobra is currently labeled for control of large (15 to 36 inches) broadleaf weeds, such as velvetleaf, giant ragweed, jimsonweed and burcucumber [State Local Need (SLN's) labels for Maryland, Delaware and Virginia]. Expect some crop injury when using Cobra. The addition of 2,4-DB (2 ounces) is recommended for help in controlling morningglories.

8 SOYBEAN WEED MANAGEMENT GUIDE 45 Rate Remarks Active ingredient cloransulam lb FirstRate 84DF ** Flexstar see Reflex thifensulfuron Harmony GT 75DF ** Unity WDG 75WDG** Synchrony XP 28.4XP ** imazethapyr Pursuit 2AS ** Extreme 2.17EC Raptor 1AS ** imazamox fomesafen Reflex 2LC ** Flexstar HL 1.88ME ** Resource 0.86EC ** flumiclorac 0.3 oz lb oz oz oz lb 4 fl oz 1.5 qt lb 5.0 oz lb pt pt lb oz FirstRate water-dispersible packets are not soluble in liquid fertilizer solutions; premixing in water is required. Apply before 50 percent flowering stage of soybeans. UAN will improve velvetleaf control. For adequate velvetleaf control, add 1 gallon of liquid nitrogen solution per acre. Use of STS varieties will reduce the risk of injury. Synchrony XP can be applied to non-sts soybean varieties at oz/a use rate or to STS varieties only at the 0.75 oz/a rate. Harmony GT, Unity WDG, and Synchrony XP labels state that the first trifoliate leaf of the soybean is fully expanded before the application is made. Apply early POST when weeds are actively growing and before most exceed a height of 3 inches and before soybeans begin to bloom. Only one application of Extreme can be made per soybean growing season. Extreme can only be applied to soybean varieties designated Roundup Ready. Observe rotational restrictions for products containing imazethapyr. Apply early POST when weeds are actively growing and before most exceed 3 inches in height and before soybeans begin to bloom. Occasionally, internode shortening and/or temporary yellowing of soybeans may occur, especially if under environmental stress. When adequate soil moisture is present, Raptor will provide residual activity of susceptible germinating weeds. Observe rotational restrictions for products containing imazamox. Apply when weeds are small and before weeds reach maximum growth stages described on the label, and before soybeans begin to bloom. Do not apply Reflex or Flexstar more than once every 2 years. Observe labeled rotational crop restrictions. The addition of 2,4-DB (2 ounces) is recommended for help in controlling morningglories. Flexstar can cause more soybean injury than Reflex. Apply 4 to 8 ounces of Resource as a broadcast POST spray to 6- to 10-leaf velvetleaf using higher rates for larger velvetleaf. Resource has activity against several other weeds when they are in the two- to three-leaf stage, including cocklebur, lambsquarters, common ragweed, jimsonweed, pigweed species, and prickly sida, but control declines on larger weeds.

9 SOYBEAN WEED MANAGEMENT GUIDE 46 Rate Remarks Active ingredient glyphosate ae formulations Roundup Original Max 4.5L ** Roundup PowerMAX or WeatherMax 4.5 L ** Touchdown HiTech 5SL ** Touchdown Total 4.17 SL** or other available formulations lb ae 2-4 pt pt pt pt es Extreme 2.17EC Sequence 5.25 EW Scepter 70DG ** imazaquin chlorimuron + thifensulfuron Synchrony XP 28.4XP ** 1.5 qt pt lb oz lb lb oz For use only on soybean varieties designated Roundup Ready. This program is most effective in narrow-row or drilled soybeans. Roundup may be applied POST from cracking through the full flowering stage. Make initial POST applications of glyphosate at the following per acre rates (Roundup Original Max, PowerMAX, or WeatherMax 22 to 35 oz; Touchdown HiTech 20 to 30 oz; Touchdown Total 24 to 36 oz), and if necessary, sequential treatments at these per acre rates (Roundup Original Max, PowerMAX, or WeatherMax 11 to 22 oz; Touchdown HiTech 10 to 20 oz; Touchdown Total 12 to 18 oz). Adjust application rates for individual weed species and weed size as directed by the label. For control or suppression of perennial weeds, apply glyphosate at the following per acre rates (Roundup Original Max, PowerMAX, or WeatherMax 22 to 44 oz; Touchdown HiTech 20 to 40 oz; Touchdown Total 24 to 48 oz). Use a nonionic surfactant at 0.25 to 0.5 percent v/v in all applications of Roundup Original Max, and at 0.25 percent v/v with Touchdown HiTech. Do not use surfactant with Roundup WeatherMax. Adjuvants are optional with Roundup PowerMAX or Touchdown Total. Care must be used to avoid drift to adjacent crops or other desirable vegetation. Single in-crop applications must not exceed 44 oz/a of Roundup Original Max, PowerMAX, or WeatherMax, 40 oz/a of Touchdown HiTech, or 48 oz/a Touchdown Total. Combined total in-crop applications must not exceed 2 qt/a/season of Roundup Original Max, PowerMAX, or WeatherMax, 1.8 qt/a/season of Touchdown HiTech, or 2.2 qt/a/season of Touchdown Total. Only one application of Extreme can be made per soybean growing season. Apply after crop emerges but before weeds are 12 inches high. Do not apply when weeds and soybeans have been subjected to temperature or moisture stress. Observe rotational restrictions for products containing imazaquin. Synchrony XP at the 0.75 oz/a use rate is for use only on soybean varieties designated as STS in the variety name. Make applications to small, actively growing weeds after the first trifoliate of the soybean has fully expanded. Carefully observe crop rotation intervals, and note that extended crop rotation intervals apply when Synchrony XP is applied following preemergence applications of other sulfonylurea or imidazolinone herbicides. Synchrony XP can be used at a reduced rate of oz/a on non-sts soybeans for control of 1-4 inch cocklebur and pigweed, and suppression of 1-4 inch lambsquarters, jimsonweed, common ragweed, smartweed, and velvetleaf.

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11 SOYBEAN WEED MANAGEMENT GUIDE 48 Postemergence Grass s: fluazifop Fusilade DX 2EC ** es Fusion 2.56EC ** sethoxydim Poast 1.5L ** Poast Plus 1L ** clethodim Select 2EC ** Select Max 1EC ** quizalofop Targa 0.88EC ** Assure II 0.88EC ** POST lb Apply to actively growing grasses at the rate and growth stage indicated on the label for the individual grass 6-12 oz species with a minimum of 10 gallons of water per acre and 30 to 60 pounds per square inch. Do not use flood nozzles. Apply before soybeans begin to bloom oz POST lb Apply to actively growing grasses at the rate and size indicated on the label for the individual grass species with 1-2 pts 10 to 20 gallons of water per acre and 40 pounds per pts square inch. Do not use flood-type nozzles. POST lb Apply to actively growing grasses in 10 to 40 gallons of water. See label for tank-mix instructions and grass 6-8 oz growth stages oz POST lb Apply to actively growing grasses in 10 to 40 gallons of water per acre using flat fan or hollow cone nozzles. Do 5-12 oz not apply within 80 days of harvest or after pod set oz