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ISSUE 6  June 11, 1998

 

SECTION 18 FOR MUSTER ON CANOLA GROWN FOR SEED

Muster 75DF (DuPont)
    Mode of action:
ALS inhibitor
    a.i.:
ethametsulfuron
    Crops:
Canola grown for seed.
    Comments:
Muster has been cleared for use under Section 18 Crisis Exemption only in the state of ND for control of wild  mustard in ONLY canola grown for seed. Effective use date is June 4 and end use date is July 1, 1998. Muster is a DF          formulation as are other DuPont products. Muster is not volatile but can drift through particle movement and injure sensitive crops. Canola treated with Muster should not be grazed or feed to livestock.

    Apply Muster at 0.3 oz DF/A with a nonionic surfactant at 0.25% v/v (1 qt/100 gal water) to wild mustard at the cotyledon to 6-leaf stage and Canola at the 2-leaf stage to beginning of bolting. A rain-free interval of 4 to 6 hours must be maintained after application. Muster can be tankmixed with Assure II herbicide (follow the Assure II label for rates and instructions). Use only a nonionic surfactant adjuvant with the Muster + Assure II tankmix. Use at least 5 GPA for ground application. Do not apply by aerial application. Apply Muster at least 60 days prior to harvest.

    Observe the following crop rotation restriction following Muster application: 10 months for HRS and durum wheat, barley, oat, and flax. 22 months for Canola, lentils, peas, fababeans, tame mustard, alfalfa, canary grass, dry beans, fescue, and red clover. For all other crops field bioassay at 22 months. Corn falls under the 22 month and bioassay restriction. Use extra caution for crop rotation when applying Muster on land previously treated with a residual ALS herbicide, such as, Finesse, Ally, Amber, Assert, Peak. Consult label for field bioassay instructions.

Kochia has become resistant to Muster and other herbicides with ALS inhibition mode of action. Follow other restriction contained on the label.

Muster has been registered in Canada for the last few years for control of wild mustard, hemp nettle, smartweed, spring seedlings of flixweed, and suppression of field pennycress (also know as stinkweed, fanweed, or frenchweed or even Thlaspi arvensis for you that speak Latin and have an affinity remembering scientific names.). Some activity may be seen on redroot pigweed.


EXPANSION OF COUNTIES FOR H-273 SECTION 18

The EPA has allowed the addition of the six counties in ND for the Section 18 allowing Herbicide 273 in canola. The added counties are Bottineau, Rolette, Pierce, McHenry, Renville and Ward.

1998 NEW HERBICIDE REVIEW (Cont.)

Cobra (Valant)
    Mode of action: PPO inhibitor
    a.i.:
lactofen
   Crops: Soybean
   Comments: Labeled for white mold suppression at 6 to 12.5 fl oz/A Applications should be made at or near soybean bloom. Addition of oil additives at 1 to 2 pt/A is required. The effect of white mold suppression is not a fungicidal response but involves Systemic Acquired Resistance (SAR). See label for allowed tankmixes and other information.

Select/Prism (Valent)
    Mode of action: ACCase inhibitor
    a.i.:
clethodim
   Crops: AGSCO will be the only distributor of Prism. Select registration has been granted on all dry bean types and alfalfa (including sainfoin, holy clover, and birdsfoot trefoil). Registration expected later on lentils, lupin, and peas.
   Comments: Excellent control of annual and perennial grasses at 6 to 8 fl oz/A. Always use an oil adjuvant at 1% v/v or 1 gal/100 gal of water. Do not apply Select within 30 days of dry bean harvest. Do not apply Select within 15 days of grazing, feeding, or harvesting. Allow a 60 day grazing, feeding, or harvesting restriction if tankmixed with 2,4-DB for weed control in alfalfa. Two-way tankmixes of Select plus Basagran is labeled in dry beans. Two-way tankmixes of Select plus Pursuit, or Buctril are labeled in alfalfa.

Spirit (Novartis) - Both ALS - NOT IN ND
    a.i.: primisulfuron (Beacon) + prosulfuron (Peak) in 3:1 ratio or 0.575 oz/A:0.25 oz/A)
    Crops: Corn
    Comments:
Same ingredients as Exceed except contains a higher ratio of Beacon and less Peak for use in some northern U.S. geographic locations to reduce risk of carryover. See label.

Starane (UAP) - IN U.S.
Attain (Dow) - IN CANADA
    Mode of action:
Plant growth regulator
    a.i.: fluroxypyr
    Crops: Wheat and barley.
    Comments: A Section 18 label has been approved for Starane for use in wheat and barley in North Dakota. The herbicide is available for control of sulfonylurea-resistant kochia. Starane should be tank-mixed with other herbicides to increase the spectrum of weeds controlled. Weeds controlled when Starane is tank-mixed with 2,4-D include kochia, common cocklebur, common lambsquarters, common ragweed, field pennycress, marshelder, pigweed, Russian thistle, shepherdspurse, volunteer sunflower, and wild mustard. Apply Starane at 0.67 pints per acre in a minimum of 8 gallons of water per acre by ground or 3 gallons by air. Cost is about $8.20 per acre at the labeled rate. Apply to actively-growing wheat and barley from the 2-leaf up to and including the flag leaf stage. Starane may be tankmixed with any product allowing such. So the only products that restricts such use would be all the AgrEvo small grain products: Hoelon, Dakota, Tiller, Cheyenne and Puma because their label states that only products which appear on their label may be mixed. However, when tankmixing with legal tankmix products, observe the most restrictive label of the product used. Small gain tolerance of Starane is very good. For example, wheat injury from the use of Starane plus 2,4-D at four 1997 trial locations in ND ranged from 0 to 3%. Starane is systemic and has a growth regulator (auxin) type of mode-of-action. The herbicide does not have carryover restrictions for crops grown the following year. Refer to the label for additional details. The label must be in the user's possession during Starane application.

    Starane has been researched extensively for many years but never received registration due to limited weed spectrum. UAP is pursuing registration in U.S. through Dow. Attain in Canada is composed of 180 g/L fluroxypyr and 564 g/L 2,4-D LV ester. Fluroxypyr alone has a limited broadleaf weed spectrum but provides excellent ALS resistant and susceptible kochia control. Tests indicate it also controls plant growth regulator tolerant kochia. Provides control or partial control of wild buckwheat and nightshades.

    Starane is in the pyridine or Tordon chemistry but fortunately has rapid microbial breakdown with no residue or crop rotation restriction the following year. Do not drift Starane. Starane may kill or injure ALL legume crops, sugarbeet, sunflower, and potato. Starane is marketed through UAP/Ostlund. Labels can be obtained through the Dept of Ag or Ostlund.

Sythe (Mycogen)
    Mode of action:
Non classified
    a.i.: Pelargonic acid and related fatty acids
    Crops: Burndown and noncropland. Labeled on high value crops.
    Comments: 2.5 to 5 gallons/A. Contact, nonresidual product. Active ingredients is common in nature - grape skins have 400 ppm of ai. Claims to synergize Roundup by enhancing Roundup uptake for greater weed control.

Touchdown 5E (Zeneca)
    Mode of action:
EPSP synthase inhibitor
   a.i.: Trimethyl sulfonium salt of glyphosate (NOT sulfosate).
    (Same active ingredient as Roundup but a different salt.
    Roundup Ultra = glyphosate - isopropylamine salt
    Touchdown = glyphosate - trimethyl sulfonium (trimesium) salt.
   Crops: Burndown for corn and soybean, and in future, wheat.
   Comments: Previously registered only in noncrop uses. Touchdown 5E contains adjuvants as Roundup Ultra but does not restrict addition of additional adjuvants. Touchdown is affected by water quality and salt antagonism as Roundup Ultra.

 

CHOOSING ADJUVANTS WITH HERBICIDE

    Several POST herbicides allow use of nonionic surfactant, petroleum oil additives, methylated seed oil additives, and nitrogen fertilizer. Questions about which adjuvant to continually arise. MSO type additives have given greater weed control than petroleum oil additives and nonionic surfactants (NIS) but cost up to 2 to 3 times more. The added cost of MSO’s has deterred people from using this class of adjuvants.

    Some herbicide labels restrict use of oil adjuvants and recommend only the use of NIS alone or combined with nitrogen based fertilizer solutions. For example, oil additives are not allowed with Banvel/Clarity on corn applied alone or in tankmix combination with Accent. Follow label directions for adjuvant selection. Where labels allow use of oil additives, a petroleum oil based adjuvant referred to as crop oil concentrates (COC) or methylated seed oil (MSO) adjuvants may be used. The term crop oil concentrate is misleading and incorrect. The base substance in COC is petroleum oil based ingredients not crop oil based.

    NDSU research has shown wide difference in adjuvant enhancement of herbicides. However in many studies no or small differences have been observed based on environmental conditions at application, growing conditions of weeds, rate of herbicide used, and size of weeds. For example, under warm, humid conditions with actively growing weeds, NIS adjuvants + nitrogen fertilizer has given equal weed control as oil type additives. The following are conditions where MSO type additives may give greater weed control than other adjuvant types.

Conditions that support use of MSO type adjuvants:

1.  Low humidity, hot weather, lack of rain, and drought stressed weeds or weeds not actively growing due to some condition   causing stress.
2.  Weeds larger than recommended on the label.
3.  Herbicides used at reduced rates.
4.  Target weed or weeds are somewhat tolerant to the herbicide. For example, control of wild buckwheat, biennial wormwood, common lambsquarters or ragweed with Pursuit or Raptor, or control of yellow foxtail with Accent.
5.  When university data supports use. Only some herbicides give greater weed control when used with MSO type adjuvants. For example: Accent, Pursuit, Raptor has shown greater weed control when used with an MSO type adjuvant compared to a NIS. Also, Roundup, Roundup Original, Roundup Ultra, Generic Roundup, Touchdown (glyphosate) should never be used with an oil adjuvant because Roundup is very water soluble (water + oil don’t mix) and the added cost of an MSO is not necessary.

    Quad 7, a non-oil based adjuvant on the market this year from AGSCO, may provide enhancement of Accent, Pursuit, and Raptor similar to MSO type adjuvants. Quad 7 may be used in those situation where oil adjuvants are restricted. For example, Banvel/Clarity labels restrict oil adjuvants used alone or in tankmix with Accent on corn. Quad 7 is used at 1% v/v (1 gal/100 gal of water) and cost $0.75/A at 5 GPA or $1.50/A at 10 GPA which is less than the cost of Scoil or other MSO type adjuvants which is approximately $2.50 to $3.00/A at the 1.5 pt/A rate. Many people have indicated intention of using Quad 7 instead of an MSO type adjuvants and excellent performance may result. However, under conditions of 1 through 5 listed above MSO type adjuvants may provide greater weed control and herbicide enhancement than Quad 7.

    In summary: Accent, Pursuit, or Raptor with Quad 7 will NEVER provide greater weed control than when applied with Scoil or an MSO based adjuvant!

    You may get what you pay for!

Richard Zollinger
NDSU Extension Weed Specialist


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