CT-2
A no-till planted field does not have to mean a field full of weeds. No-tillage systems use herbicide applications instead of cultivation for weed control. A greater reliance on herbicides requires attention to detail--types of weeds, weather trends, cropping patterns, soil type--in order to control weed populations without adversely affecting the environment. The first few years of no-tillage may require higher herbicide inputs. However, many long-term growers claim once no-till is established, herbicide costs generally decrease and become competitive with conventional systems.
Successful weed control in no-tillage requires:
* accurately identifying weeds
* proper timing of herbicide treatments
* scouting and monitoring fields for problem areas
* spot spraying herbaceous and woody perennials
* keeping fence rows and field borders free of aggressive weeds
* assuring even distribution of crop residue after harvest
Without deep tillage weed seeds stay near the soil surface instead of being buried too deep for germination. Small-seeded broadleaf weeds and annual grasses can germinate under crop residue as shown in Figure 1. Large-seeded weeds, such as velvetleaf and common cocklebur, need deeper soil placement to germinate. With continued no-tillage large-seeded weed populations tend to decline. Both simple perennial and creeping perennial weeds multiply in a no-tillage system. Creeping perennials also tend to be a problem in conventional tillage systems although tillage controls simple perennials. Table 1 lists the weeds commonly found in no-till planted fields (see page 2).
For the best results apply early preplant herbicide treatments before germination of summer annual weeds. The timing of these treatments range from ten to 45 days prior to planting of the crop, see Tables 2 and 3. Applying herbicides early in the season, when rains are more frequent, insures activation of the herbicides. Early application also helps spread out the spring work load. With timely herbicide applications, the fields will be free of weeds at planting, eliminating the need for a burndown treatment. Early killing of weeds also discourages insects attracted to weedy fields, such as black cutworm moths.
Winter annuals Summer annuals Simple perennials Creeping perennials
(one main taproot) - (underground creeping
rootstocks, rhizomes, or tubers)
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common chickweed common lambsquarters common pokeweed Canada thistle
henbit pigweed common dandelion hemp dogbane
purple deadnettle black nightshade wild four o'clock Jerusalem artichoke
ragwort/groundsel common ragweed curly dock bindweed
downy brome annual smartweed common milkweed
wild mustard rough (daisy) fleabane honeyvine milkweed
shepherdspurse marestail/horseweed Biennials trumpet creeper
prickly lettuce foxtail wild carrot bigroot morning glory
marestail/horseweed fall panicum common mullien horsenettle
crabgrass poison hemlock ground cherry
common burdock swamp smartweed
yellow nutsedge
johnsongrass
quackgrass
wirestem muhly
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Weeds in no-tilled fields tend to germinate throughout the season. Maintain season-long weed control with early pre-plant treatments of "full season" residual herbicides or split treatments of herbicides with medium longevity. Split applications often include applying 1/3 of the labeled herbicide rate early and the remaining 1/3 at planting. Many early preplant herbicides have burndown activity on small weeds (1" to 3"). Adding a crop oil or surfactant to the herbicide mix improves their control. Weeds greater than 3", such as winter or early summer annuals, may be present at the time of early preplant applications. Abundant weed growth may require a burndown herbicide, such as glyphosate, paraquat, or 2,4-D.
Burndown herbicides control emerged weeds before or just after planting, but prior to crop emergence. These herbicides can be combined with early preplant or preemergence treatments. Paraquat (e.g. Gramoxone Extra) works well in combination with residual herbicides. A tank mix of glyphosate (eg. Roundup) and 2,4-D broadens the spectrum of weed control. The weed species present, size, life cycle, and herbicide efficacy determines what and how much herbicide to apply.
The success of preemergence herbicide treatments depends on rainfall to activate the herbicide soon after spraying. Without moisture, herbicide performance suffers. Herbicides that are soil-applied after planting are often preferred over treatment prior to planting. Planter row-cleaners or "trash-whippers" can move herbicide-treated soil from the row to the row middles, creating weed problems in the untreated zone.
Two types of preemergence herbicide programs are common in no-tillage:
a full season program--where herbicides control weeds throughout most of the growing season, or
a short residual program--where the crop shades out later germinating weeds. Postemergence treatments may be necessary for weed escapes.
Herbicide Days Before Planting
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Atrazine*, Bicep*, Bicep II* 30-45 (split a);
less than 30 (split or single);
less than 14 on coarse soil
Banvel*, Clarity,*, Marksman* 7-30??
Bladex* 15-30
Dual, Dual II, Frontier 30-45 (split a);
Harness, Micro-Tech, Partner less than 30 (split or single)
Bullet*, Guardsman*, 30-45 (split a);
Harness Xtra* less than 30 (split or single)
Extrazine II*, Surpass, up to 30
Surpass l00*, TopNotch
Lariat* less than 30 (single);
less than 45 (split)
Broadstrike + Dual 30; less than 14 on coarse soil
Broadstrike Plus 30
Pursuit (imi corn May be applied EPP (number
hybrids only) of days not mentioned in label)
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*These herbicides will burndown small (1"-3") broadleaf weeds. Add
crop oil or surfactant for improved control. If weeds are taller than
3" or one of the other early preplant (EPP) treatments are applied
then add a burndown herbicide such as Gramoxone Extra, Roundup,
Bronco, or 2,4-D ester according to label directions,
Split applications = 2/3 rate EPP and 1/3 at planting;
single applications = total rate applied EPP
Postemergence treatments work well in a no-tillage system where no soil-applied treatments are planned and also in fields where perennial weeds, such as johnsongrass or Canada thistle are a problem. Soil type or the amount of crop residue present generally does not affect postemergence treatments. Postemergent application does depend on proper timing and correct identification of the target weeds. Successful total postemergence programs occur in fields that are weed-free when planted.
No-tilling in to old hay fields, set-aside, or idle land presents a special challenge. To get a good kill of both grass and legume sods takes advanced planning. Generally products like glyphosate (e.g. Roundup) easily kill grass sod in the fall. Spring applications require higher rates of Roundup than fall applications for better kill. Spring treatments of Gramoxone plus atrazine can provide good control of a mixed stand of grass and legumes before planting corn. The sod needs to be actively growing with sufficient growth for translocative herbicides, such as glyphosate, dicamba (e.g. Banvel) and 2,4-D to be effective. Sod must be at a certain height and environmental condition before it is sprayed. The herbicide application may delay planting. Corn planted into a legume sod has more control options than for soybeans. Growth regulator herbicides, such as 2,4-D and dicamba, used postemergence in corn control escaped legumes, but not in soybeans.
Quick canopy closure provides shade and controls late germinating weeds. Poor crop stands, wide rows, and limited shoot growth result in weedy crops. Without cultivation crop competition becomes an important segment of weed control in no-tillage. Another form of weed control often utilized in no-tillage systems is the establishment of a cover crop prior to planting corn or soybeans. After killing the cover crop with nonselective herbicides the resulting dead mulch serves as a "barrier" to several kinds of small-seeded weeds. Rye and wheat seeded in the fall are the two most common types of cover crops (Figure 2). Not only does the dead rye or wheat straw help smother emerging weed seedlings, but many researchers report the presence of allelopathic chemicals leached from the straw suppress weeds.
Both simple and creeping perennial weeds can become a problem in no-tillage systems. Simple perennials produce a shoot annually from a main taproot. Simple perennials rarely survive in full-till systems. Creeping perennials reproduce by underground vegetative structures that provide these weeds with both competitive and survival advantages. Creeping roots, rhizomes, and tubers store food and provide numerous buds capable of generating new plants. Creeping perennials can be a problem in both conventional tillage and no-tillage systems.
Perennial weeds, both grasses and broadleaves, can be difficult to control with herbicides in a cropping system. Herbicide rates used in corn and soybeans are not high enough to provide good control of the root system of most perennial broadleaf weeds. Translocated herbicides must be applied at the proper stage of weed growth for optimum control. Generally, perennials effectively move the herbicide into their root system when sprayed prior to full bloom in the spring or when new growth appears in the fall.
Herbicide Days Before Planting
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Command prior to field green-up and
before April 1
Canopy *, Lorox Plus* up to 30
Dual, Micro-Tech, Partner 30-45 (splita); less than 30
(split or single)
Prowl up to 45
Sencor*, Lexone*, Turbo* 0-30
Pursuit, Pursuit Plus, Scepter up to 45
Squadron, Detail
Broadstrike + Dual up to 30;
less than 14 for coarse soils
Frontier may be applied EPP, label
recommends adding 2-4
ounces more per acre for
this application
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* These herbicides will burndown small (1"-3") broadleaf weeds. Add
crop oil or surfactant for improved control. If weeds are taller than 3" or
one of the other EPP treatments are applied then add a burndown
herbicide such as Gramoxone Extra, Roundup, Bronco, or 2,4-D
ester according to label directions.
a Split applications where 2/3 of labeled rate applied EPP and remaining
1/3 at planting.
For broadleaf perennial control in corn, the use of growth regulator herbicides such as 2,4-D, dicamba, and clopyralid (e.g. Stinger ) give "top-kill" as well as provide some control of the root system. Some perennial grass species can be controlled with nicosulfuron (e.g. Accent ), and primisulfuron (e.g. Beacon).
Increasing the crop competition to weeds by narrowing the rows and using a postemergence herbicide provide some control of broadleaf perennial weeds in soybeans. Several grass-specific herbicides labeled for soybeans work on perennial, weedy grass species. With any herbicide program, complete control of an entire perennial root system is unlikely with one herbicide application. Follow-up applications the next season(s) are necessary to achieve the desired level of control. Controlling perennial weeds in no-till systems takes persistence.
Controlling perennial weeds with herbicides often calls for special application methods.
* Use wipe-on applicators to apply nonselective translocated herbicides, such as glyphosate (e.g. Roundup) to weeds taller than the crop.
* Spot treat to control or suppress perennials prior to planting, in in the crop, and at preharvest.
* Monitor fence rows, field borders, and other non-crop areas. Spray perennial weeds that can spread into fields.
* Remove by hand simple perennial weeds such as pokeweed and curly dock. A large portion of the root or crown must be removed.
Crops have now been developed that are resistant or highly tolerant to certain herbicides. Examples of herbicide tolerant crops include Pursuit tolerant (imi) corn, STS soybeans, Roundup Ready soybeans, Poast Compatible corn, and Liberty Link corn. These special crops may provide an option for controlling "hard-to-control" weeds in no-tillage systems. For example, Synchrony STS, a premix of Classic and Pinnacle, provides good top-kill of common milkweed. Roundup Ready soybeans allows the use of Roundup, a non-selective herbicide, to be applied postemergence to the crop and weeds. Higher labeled use rates and split applications of Roundup will help to control various perennial weeds in no-till soybeans that have been missed with standard herbicide programs. Contact a local seed dealer for more information.
Changes in tillage influence weed populations. Annual grasses, small-seeded broadleaves, and perennial weeds become more prevalent with no-tillage - while large-seeded broadleaves decline over time. Correct identification of weeds and their life cycles are essential when selecting the proper herbicides for their control. Without tillage, dependency on herbicides to control weeds increases. Preplant herbicide treatments, with or without burndown herbicides, must provide a weed-free field at planting and several days beyond. Early weed control allows the crop to become established without weed competition. Control grass or legume sods. In the fall before planting a crop the following spring. For optimum control, treat perennial weeds prior to flowering or when new growth shows in the fall.
The following table--Problem Weeds in No-till--recommends herbicide treatments to control specific weeds. For more information on weed control in cropping systems, refer to "Weed Control Guidelines for Indiana", WS-16, or the Purdue University "Herbicide Selector" computer program. Both can be obtained from your county Purdue Cooperative Extension office.
"Weeds of the North Central States," NCR-281. University of Illinois.
Weed Crop Herbicide Remarks
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Annuals-apply herbicide to weeds that are small and actively growing
Horseweed Corn/Soybeans Roundup (1 pt/a) +2,4-D (1 pt/a) Apply as a burndown treatment before planting. Apply the
(marestail) Roundup +2,4-D treatment with a nonionic surfactant 0.5% v/v
in 10 gallons of water per acre when the weeds are 6" or less in
height. For the 2,4-D (2 pt/a) treatment, wait at least 30 days
before planting soybeans.
Corn Banvel/Clarity Apply postemergence 1 pt/a (0.5 pt/a on coarse soils and soils
with less than 2% organic matter) to weeds that are small and
actively growing. See label for corn height restrictions.
Atrazine and/or Bladex + 2,4-D or Apply before planting as a burndown treatment. This
Banvel (label rates) treatment will also give residual control.
Soybeans Gramoxone + Sencor/Lexone Apply before planting as a burndown treatment when weeds are
(label rates) very small and actively growing.
Canopy (label rates) Apply before planting as a burndown treatment when weeds
are less than 3" tall. Add a COC to the spray mix.
Classic Apply 0.75 oz/a plus a COC postemergence before the marestail
plants are 6" tall.
Roundup Roundup (postemergence 1 - 2 pt/a for control.
Ready Soybeans in crop)
Ragwort Corn/Soybeans Roundup 1.5-2 pt/a Apply as a burndown application before planting to weeds
(groundsel) in the rosette stage. 2,4-D is not effective in controlling ragwort.
Soybeans Canopy, Lorox Plus, Apply a full rate as a burndown application before planting to
Sencor/Lexone weeds in the rosette stage. Add a COC to improve control.
Prickly lettuce Corn/Soybeans Roundup (1 pt/a) +2,4-D (1 pt/a) Apply as a burndown treatment before planting. Apply the
or 2,4-D ester ( 2 pt/a) Roundup + 2 4-D treatment with a nonionic surfactant (0.5% v/v)
in 10 gallons of water per acre when the weeds are 6" or less in
height. For the 2,4-D (2 pt/a) treatment, wait at least 30 days before
planting soybeans.
Prickly lettuce Corn Atrazine atrazine + Bladex, or Apply as a burndown treatment before planting to weeds that are
Banvel (label rates) less than 2" tall Add a COC with the atrazine treatments.
Soybeans Canopy, Lorox Plus, Apply before planting as a burndown treatment when weeds
Sencor/Lexone (label rates) are less than 3" tall. Add a COC to the spray mix.
Mustards Corn/Soybeans Roundup (1 pt/a) + 2,4-D (1 pt/a) Apply as burndown treatment before planting. Apply the Round-
or 2,4-D ester (2 pt/a) up + 2,4-D treatment with a nonionic surfactant (0.5% v/v) in 10
gallons of water per acre when the weeds are 6" or less in
height. For the 2,4-D (2 pt/a) treatment, wait at least 30 days
before planting soybeans.
Gramoxone Extra 1.5 - 3 pt/a Apply as a burndown treatment before planting. Add a
depending on size of weeds nonionic surfactant or COC and apply in a minimum of 20
gallons of water per acre.
Corn Atrazine and/or Bladex (label rates) Apply as a burndown treatment before planting to weeds
that are less than 2" tall. Add a COC.
Soybeans Canopy, Lorox Plus, Apply before planting as a burndown treatment when weeds are
Sencor/Lexone(label rates) less than 3" tall. Add a COC to the spray mix.
Perennials - apply translocative herbicides to bloom and/or on fall regrowth
Bindweed Corn 2,4-D ester 0.5 - 0.75 pt/a Apply postemergence in spring when leaves are fully expanded
or amine 1 pt/a or apply pre-harvest after brown silk stage in corn. The ester
formulation is preferred. Use drop nozzles when corn is over 8" tall.
Banvel/Clarity 0.5 - 1 pt/a Use the 0.5 pt rate of Banvel or Clarity postemergence on
sandy soils. On corn between 8 and 36" use Banvel at 0.5 pt/a.
Soybeans Blazer, Cobra, Basagran, Vines may be suppressed by these postemergence applications.
Reflex, FlexStar (label rates ) Control can be improved by adding 2 fluid ounces/a of 2,4-DB.
Roundup Roundup 2 - 4 pt/a will control or suppress the weed. Repeat application
Ready (postemergence in crop) may be necessary. See label for sequential treatment rates.
Soybeans
Bigroot Corn 2,4-D amine 1 pt/a or Use postemergence on actively growing plants that have
morningglory ester 0.5 - 0.75 pt/a sufficient vine growth to absorb the herbicide (10"- 24 ").
Soybeans Cobra 12.5 oz/a Postemergence. Suppression of vines mostly.
Roundup Ready Roundup 2 - 4 pt/a will control or suppress the weed. Repeat applica-
Soybeans (postemergence in crop) tion may be necessary. See label for sequential treatment rates.
Canada thistle Corn Stinger 0.33 - 0.67 pt/a Apply as a postemergence broadcast or spot treatment on
Canada thistle shoots that are 4" to bud stage. Do not apply
after the corn is 24" tall; do not apply more than 0.67 pt/a per year.
Banvel/Clarity 0.5-1 pt/a or 2,4-D Use the 0.5 pt rate of Banvel or Clarity postemergence on
amine 1 pt/a or ester 0.5-0.75 pt/a sandy soils. On con~ between 8"- 36 " use Banvel at
0.5 pt/a. Mostly suppresson of shoots.
Beacon 0.76 oz/a or Apply postemergence when corn height is between 4" - 20"
Exceed 0.88 oz/a tall (Beacon) or 4" - 48 (Exceed), and to Canada thistle
plants between 2" - 9" tall (Beacon) or 1" - 6" (Exceed). Mostly
shoot suppression.
Laddok S-12 at 2.33 pt/a Shoot suppression only. Apply postemergence when
Canada thistle is 8" - 10" tall. Use with 2 pt/a COC.
Buctril 1.5 pt/a or Buctril/atrazine Shoot suppression only. Apply postemergence to weeds
2 - 3 pt/a From 8" tall to the bud stage or up to tassel emergence on
corn. Do not add spray additives.
Corn/Soybeans Roundup 2 - 3 qt/a Spot treat in crop (will kill crop where treated). Or apply after
harvesting corn or as a preharvest application in soybeans.
Weeds should be actively growing.
Soybeans Basagran, Blazer, Cobra, Apply postemergence. Most effective when used in
Reflex, FlexStar (label rates) conjunction with narrow rows, i.e., crop shading.
Roundup Ready Roundup (postemergence in crop) 2-4 pt/a will control or suppress the weed. Repeat application
Soybeans may be necessary. See label for sequential treatment rates.
Common milk- Corn 2,4-D ester 0.5 - 0.75 pt/a or Apply postemergence. Use drop nozzles when corn is taller
weed and amine 1 - 1.5 pt/a than 8".
Hemp dogbane
2,4-D amine 1 - 2 pt/a or ester Apply mid- to late-season after corn silks have turned
1 - 2 pt/a brown and plants are actively growing and have adequate
foliage.
Banvel/Clarity 0.5 to 1 pt/a See Canada thistle comments
Beacon 0.38 oz/a + 2,4-D or Banvel Apply postemergence to corn and to small milkweed/hemp
(label rates) or Exceed 0.88 oz/a + dogbane plants. See label for corn height.
2,4-D or Banvel(label rates)
Corn/Soybeans Roundup 33% solution Apply with wiper applicator (rope-wick or sponge) only when
there is a sufficient height differential between weed and crop.
Roundup 1-2% solution Spot treat plants that are actively growing. Will kill crop
where treated.
STS Soybeans Synchrony STS 0.85 oz/a For shoot suppression of common milkweed. Use only on
STS soybean varieties. See label for rate of adjuvants.
Roundup Ready Roundup (postemergence in crop) 2 - 4 pt/a will control or suppress the weed. Repeat application
Soybeans may be necessary. See label for sequential treatment rates.
Honeyvine Corn 2,4-D ester 0.5-0.75 pt/a or 2 4-D Apply postemergence. The ester formulation of 2,4-D is
milkweed amine 1 pt/a or Banvel 0.5 - 1 pt/a preferred; however, a combination of 2,4-D and Banvel maybe
or 2,4-D + Banvel at half rates better than 2,4-D used alone. Check Banvel label for restrictions.
Beacon 0.76 oz/a or Apply postemergence. Suppression of shoots only.
Beacon + 2 4-D or Banvel
(label rates)
Exceed 0.88 oz/a + Beacon or
Marksman (label rates)
Jerusalem Corn Banvel/Clarity 0.5 - 1 pt/a Apply postemergence when weeds are 8" - 16 " tall.
artichoke or Banvel +2,4-D at half rate Use the 0.5 pt rate of Banvel or Clarity on sandy
soils. On corn between 8" - 36" use Banvel at 0.5 pt/a.
Stinger 0.25 - 0.5 pt/a Apply postemergence to weeds up to the 5-leaf stage. Do not
apply more than 0.67 pt/a per year if retreatment is necessary.
Do not apply to corn taller than 24".
Beacon 0.76 oz/a Apply postemergence to 1" -4" tall Jerusalem artichoke plants.
Soybeans Pursuit 4 fluid oz or 1.44 oz DF/a Apply Pursuit postemergence to weeds that are 6"- 8" tall
or Classic 0.75 oz/a and Classic to weeds less than 8" tall. See label for rate of
surfactants.
STS Soybeans Synchrony STS 0.85 oz/a Apply postemergence to weeds that are 2"-6" tall. Use only on
STS soybean varieties. See label for rate of adjuvants.
Roundup Ready Roundup (postemergence in crop) 2 - 4 pt/a will control or suppress the weed. Repeat
Soybeans application may be necessary. See label for sequential treatment
of surfactants.
Corn/Soybeans Roundup 1 - 2% solution Spot treat plants that are actively growing. Will kill crop where
treated.
Swamp smart- Corn Banvel/Clarity 0.5-1 pt/a Use the 0.5 pt rate of Banvel or Clarity postemergence on
weed sandy soils. On corn between 8" -36" use Banvel at 0.5 pt/a.
Trumpetcreeper Corn/Soybeans Roundup 2 - 3 qt/a Spot treat in crop (will kill crop where treated). Or apply after
harvesting corn, or as a preharvest application in soybeans.
Weeds should be actively growing.
Corn Banvel/Clarity 1 pt/a Apply as a postemergence treatment when corn is between
spiking and 8" tall. Mostly suppression of vines.
Soybeans Cobra, Blazer, Reflex, FlexStar Apply postemergence. Top suppression only. Most
effective when used in conjunction with narrow rows, i.e.,
crop shading.
Roundup Ready Roundup (postemergence in crop) 2 - 4 pt/a will control or suppress the weed. Repeat
Soybeans application may be necessary. See label for sequential
treatment rates.
Pokeweed Corn Banvel, Beacon, Exceed, or Apply as a postemergence treatment when weeds are small and
Permit (label rates) actively growing. See label for weed height.
Corn/Soybeans Roundup 1 - 2% solution Spot treat weeds that are less than 24" tall. Will kill crop
where treated.
Roundup Ready Roundup (postemergence in crop) 2 - 4 pt/a will control or suppress the weed. Repeat
Soybeans application may be necessary. See label for sequential
treatment rates.
Dandelion Corn/Soybeans 2,4-D ester 1 - 2 pt/a Apply before planting. For soybeans, do not apply less than 7
days before planting if using 1 pt/a and not less than 30 days if
applying 1 - 2 pt/a.
Control of dandelion with 2,4-D improves as air temperature
increases.
Corn 2,4-D ester 0.75 pt/a Apply as a broadcast postemergence treatment. See label for corn
height restrictions.
Brambles Corn/Soybeans 2,4-D ester 1 - 2 pt/a Apply before planting. For soybeans, do not apply less than 7
days before planting if using 1 pt/a and not less than 30 days if
applying 1 - 2 pt/a.
Roundup 2 - 3 qt/a Apply as a broadcast or spot treatment prior to planting. Also
apply as spot treatment in crop (will kill crop where treated).
Corn Banvel/Clarity, 2,4-D (label rates) Mostly suppression of top growth. Apply as a broadcast
postemergence treatment. See label for corn height restrictions.
Roundup Ready Roundup (postemergence in crop) 2 - 4 pt/a will control or suppress the weed. Repeat
Soybeans application may be necessary. See label for sequential treatment
rates.
Curly dock Corn/Soybeans Roundup 2 - 3 qt/a Apply as a broadcast or spot treatment prior to planting. Also
apply as spot treatment in crop (will kill crop where treated).
Corn Banvel/Clarity 0.5 - 1 pt/a Apply as a broadcast postemergence treatment.
Roundup Ready Roundup (postemergence in crop) 2 - 4 pt/a will control or suppress the weed. Repeat application
Soybeans may be necessary. See label for sequential treatment rates.
Yellow nutsedge Corn Laddok 5-12 at 2.33 pt/a Apply postemergence. Suppression only. Add 2 pt/a COC.
Permit 1.33 oz/a Apply postemergence to weeds that are 4" - 12" inches tall. Add a
nonionic surfactant to the spray mix.
Frontier, Harness Soil-applied treatment. Use higher rate for given soil type.
Surpass, TopNotch
Corn/Soybeans Lasso Dual, Frontier Soil-applied treatment. Use higher rate for given soil type.
Basagran 2 pt/a Apply postemergence 1.5 - 2 pt/a when plants are 6"- 8" tall.
Reapply 7-10 days later if needed. Add 2 pt/a COC with each
application.
Soybeans Classic 0.5 to 0.75 oz/a Apply postemergence. See label for adjuvant rates.
STS Soybeans Synchrony STS 0.85 oz/a Apply postemergence. Use only on STS soybeans varieties. See
label for adjuvant rates.
Rhizome or Corn Accent 0.67 oz/a Apply postemergence to 4" - 12" tall seedling johnsongrass
seedling or apply up to 1.33 oz (in split application) on rhizome
johnsongrass johnsongrass 8" - 18" tall. Use a nonionic surfactant at
1 qt per 100 gallons of spray or COC at 4 qt per 100 gallons of
spray. See label for restrictions.
Beacon 0.76 oz/a as Apply postemergence to seedling johnsongrass when 4" - 12" tall
a single split application and rhizome johnsongrass when 8" - 16" tall. Add nonionic
surfactant at 1 qt per 100 gallons of spray of COC at 1 - 4 pt/a.
See label for restrictions.
Soybeans Assure II 10 oz/a Apply postemergence to johnsongrass when 10" - 12 "tall.
For regrowth apply additional 7 oz/a to regrowth 6" - 10 "tall.
Fusilade DX 12 oz/a Apply postemergence to 8 -18" johnsongrass and retreat
6"-12"inch regrowth at 8 oz/a. Use COC or nonionic surfactant.
Poast Plus 1.5 pt/a Apply postemergence to johnsongrass 15" - 25 "tall.
Use Dash or COC. Retreat regrowth with same rate.
Rhizome or Soybeans Fusion 10-12 oz/a Apply postemergence to seedling johnsongrass from 8 - 18"
seedling inches tall. Retreat 6" - 12" regrowth at 8 oz/a. Use COC or
johnsongrass nonionic surfactant.
Select 8 oz/a Apply postemergence to johnsongrass 12" - 24" tall. Apply 6 oz/a
to regrowth.
Roundup Ready Roundup (postemergence in crop) 2 - 4 pt/a will control or suppress the weed. Repeat
Soybeans application may be necessary. See label for sequential
treatment rates.
Johnsongrass Corn/Soybeans Roundup 33%, solution Apply with wiper applicator (rope-wick or sponge) only when
there is a sufficient height differential between weed and crop.
Quackgrass Corn Accent 0.67 oz/a Apply postemergence to 4" - 10" tall quackgrass or apply tip
to 1.33 oz/a (in split application) on quackgrass up to 6" tall. Use
a nonionic surfactant at 1 qt per 100 gallons of spray or COC at 4
qt per 100 gallons of spray. See label for restrictions.
Beacon 0.76 oz/a Apply postemergence to quackgrass when 4" - 8" tall.
Control of this species is not immediate and symptoms may take
several days to develop. Add nonionic surfactant or COC.
Exceed 0.88 oz/a + Beacon See label for instructions.
or Accent(label rates)
Corn/Soybeans Roundup 1 - 2 qt/a Apply prior to planting in spring or after harvest in the fall.
Weeds should be actively growing and greater than 8" tall.
Soybeans Assure II 10 oz/a Apply postemergence when quackgrass is 6" - 10" tall. For
regrowth apply 7 oz. when quackgrass is 4 to 8 inches tall. Add
COC.
Fusilade DX 12 oz/a Apply postemergence to 6" - 10" quackgrass and to 4" - 8" tall
regrowth at 8 oz/a. Use COC or nonionic surfactant.
Poast Plus 2.25 pt/a Apply postemergence to quackgrass 6"- 8" tall and retreat
at 1.5 pt/a for regrowth. Use Dash or COC at 2 pt/a.
Quackgrass Soybeans Fusion 12 oz/a Apply postemergence to quackgrass 6"- 40" tall. Treat regrowth
with 8 oz/a. Use COC or nonionic surfactant.
Select 1 pt/a Apply postemergence to quackgrass 4" - 8" tall and on regrowth as
well. Add COC.
Roundup Ready Roundup (postemergence in crop) 2 - 4 pt/a will control or suppress the weed. Repeat application
Soybeans may be necessary. See label for sequential treatment rates.
Wirestem muhly Soybeans Assure II 8 oz/a Apply postemergence when wirestem muhly is 4" - 8" tall.
For regrowth, apply 7 oz/a. Add COC.
Fusilade DX 12 oz/a Apply postemergence to 4" - 12" wirestem muhly and apply
to regrowth at same size and rate. Use COC or nonionic surfac-
tant.
Fusion 8 oz/a See Fusilade DX comments.
Poast Plus 2.25 pt/a Apply postemergence to wirestem muhly up to 6" tall and
retreat at same rate for regrowth. Use Dash or COC.
Select 1 pt/a Apply postemergence to 4" - 8" wirestem muhly and retreat
at same rate for regrowth. Add COC.
Roundup Ready Roundup (postemergence in crop) 2 - 4 pt/a will control or suppress the weed. Repeat application
Soybeans may be necessary. See label for sequential treatment rates.
Corn Accent 0.67 oz/a See quackgrass comments.
Beacon 0.76 oz/a Apply postemergence. Suppression only.
Corn/Soybeans Roundup 1 - 2 qt/a See quackgrass comments.
Small Grain Cover Crop
Rye or Wheat Corn/Soybeans Roundup 1 pt/a Apply prior to planting. Add a nonionic surfactant at 0.5% v/v
and apply in 10 gallons of water per acre.
Gramoxone Extra 1.5 - 3 pt/a Apply prior to planting. Add a nonionic surfactant or COC and
depending on the size of the apply in a minimum of 20 gallons of water per acre.
rye or wheat
Corn Atrazine or Bladex+Gramoxone Apply as a burndown treatment prior to planting. Add a non-
(label rate) ionic surfactant or COC.
Grass/legume Sods
Orchardgrass Corn/Soybeans Roundup 1 - 2 qt/a in fall; Grass sod is easier to control with Roundup when applied in the
or fescue sod 2 - 3 qt/a in spring fall before a killing frost. Higher rates of Roundup are required
to kill grass sod in the spring before planting.
Corn Atrazine and/or Bladex+ Apply as a burndown treatment before planting. Add a COC.
Gramoxone (label rates) May require an additional treatment of atrazine or Bladex
postemergence if label allows.
Soybeans Sencor/Lexone + Gramoxone Apply as a burndown treatment before planting. Add a COC.
(label rates) May require a postemergence treatment of Poast Plus for
control /suppression of regrowth.
Alfalfa sod Corn/Soybeans Roundup 1 - 2 qt/a Apply as a burndown treatment to actively growing alfalfa in the
fall before a killing frost. For spring applications: apply
2.5 - 3 qt/a to alfalfa sod with sufficient growth.
Corn Banvel 0.5 pt/a and/or 2,4-D Apply as a burndown in the spring before planting. Sufficient
1 - 2 pt/a, or Banvel + atrazine growth of the alfalfa is required for good control.
(label rate)
Soybeans 2,4-D ester 2 pt/a Apply as a burndown at least 30 days before planting. Control
alfalfa before planting soybeans.
Clover sod Corn/Soybeans Roundup 1 -2 qt/a + Apply as a burndown before planting. For soybeans,
2,4 D ester 1 pt/a apply not less than 7 days before planting. Control
clover before planting soybeans.
Corn Atrazine + Bladex (label rate) Apply as a burndown treatment before planting. Add a
COC. May require a follow-up, postemergence treat-
ment of 2,4-D or Banvel/Clanty.
Banvel 0.5 pt/a and/or 2,4-D 1 Apply as a burndown in the spring before planting.
to 2 pt/a,or Banvel + atrazine
(label rate)
Soybeans 2,4-D ester 2 pt/a Apply as a burndown at least 30 days before planting.
Control clover before planting soybeans.
REV 12/95
Cooperative Extension Work in Agriculture and Home Economics, State of Indiana, Purdue University and U.S. Department of Agriculture Cooperating. H.A. Wadsworth, Director, West Lafayette, IN. Issued in furtherance of the Acts of May 8 and June 30, 1914. It is the policy of the Cooperative Extension Service of Purdue University that all persons shall have equal opportunity and access to our programs and facilities.