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ISSUE 8   June 25, 1998

 

WEED CONTROL AND HERBICIDE ISSUES

    1. BASF Corporation recently announced plans to purchase a majority stake in Micro Flo of Lakeland, Florida. Micro Flo offers an extensive line of crop protection chemicals, and has a formulation site in Sparks, Georgia.

    2. DuPont recently purchased Hybrinova S.A., the hybrid wheat subsidiary of Lafarge S.A., a French company.

    3. Wet weather may prevent ground application of herbicides. Pursuit and Raptor labels require oil adjuvants to be used at 1.25 gallons/100 gallons of water if the herbicides are applied by aerial application.

    4. Assure II has received Section 3, federal registration on mint.

    5. Fusion is NOT labeled for use in sunflower.

    6. I have received too many phone calls asking for information on a new sunflower herbicide for control of Canada thistle. There isn’t one so quit asking and who ever it is that is spreading the rumor - call me and tell what the herbicide is.

    Cultivation can be used until layby for Canada thistle control between sunflower rows. The only chemical option for control of Canada thistle between sunflower rows is Roundup Ultra applied through shielded application - see page 29 of the 1998 North Dakota Weed Control Guide for more information.

    7. I gather from phone calls that many are expecting ‘control’ of Canada thistle from Raptor herbicide. Raptor will not control, kill, reduce root mass, or cause considerable pain to Canada thistle no matter how bad you hope it does. Raptor applied at the full 5 fl oz/A with the most superior adjuvant to Canada thistle 4 inches or less in height will turn the growing point yellow and delay further growth of affected thistle shoots for a few weeks. It may resume growth thereafter depending on crop competition and environmental conditions. Raptor applied to Canada thistle greater than 4 inches in height at will show less response. Additional shoots are likely to arise during the growing season after Raptor application regardless of ‘control’ expectations.

    Roundup Ultra is labeled in soybean as a preharvest application. If similar success in Canada thistle ‘control’ occurs in soybeans as observed in small grains, suppress Canada thistle throughout the growing season to set-up the thistle for a fall preharvest application. See page 24 of the 1998 North Dakota Weed Control Guide of the label for additional information.

    8. The Annual NDSU Weeds Tour will not be held this year. Heavy rains have caused considerable problems with crop and weed germination and establishment, particularly with sugarbeet and corn. Some experiments were completely destroyed from excessive rain.

    Heavy soil at Casselton and NW_22 combined with excessive rain caused some experiments to be planted late and some are yet to be established. Also, with Dr. Nalewaja's anticipated retirement (hoping he will change his mind) limited research experiments were established this year.

    Because of these conditions, the Weed Science Group has decided not to hold an NDSU Weeds Field Tour. We will develop a field book with experiments at Casselton, NW_22, North of airport, and Prosper. Plots can be toured at your discretion. Call after July 5 to obtain a tour book.

    9. Section 18 for Poast on Safflower in South Dakota. Poast herbicide has received a Crisis Exemption for use to control annual grassy weeds in safflower. The special label was issued by the South Dakota Department of Agriculture. Poast has a proven record for control of foxtail and certain other annual grasses in SDSU and regional tests. Postemergence grass control options were not available with current EPA registered herbicides. The exemption expires July 1, 1998. Federal labeling is pending. Maximum rate is 2.5 pt/A; rate of 1 pt/A is suggested for foxtail or wild oat to four inches; volunteer spring cereals require 1.5 pt/A. Higher rates are required for larger stressed grasses. Add oil adjuvants at 1 qt/A. Safflower tolerance is excellent. Do not apply with 30 days of harvest.

    10. Late-season foxtail control in wheat? Significant levels of foxtail may be present in advanced_ staged wheat due to delays in herbicide application, weed escapes, or new weed flushes. Situations when foxtail herbicide use is likely not justified include: light foxtail densities (less than 30 plants/sq ft), wheat is 3_ or 4_leaf stages ahead of foxtail, and growing conditions are favorable for wheat (moderate air temperatures and adequate soil moisture). Situations when herbicides should not be used are if wheat stage is beyond what is allowed on the herbicide label or foxtail is too large for effective control. The following are foxtail herbicide limitations for use in wheat:

Stampede = 3_leaf foxtail; 4_leaf durum and 5_leaf HRS. Hoelon _ 4_leaf foxtail and wheat.
Puma (durum) _ 2_tiller foxtail; before crop jointing.
Dakota (HRS)_ 2_tiller green foxtail; before crop jointing.
Tiller (HRS) _2_tiller foxtail; before crop jointing.
Cheyenne (HRS) _2_tiller green foxtail; before crop jointing.

Read herbicide labels for details.

    11. What could one expect if Tiller (or any product containing fenoxaprop) were applied to spring wheat beyond the 6_lf stage (in an emergency situation) for foxtail or wild oat control?

   Answer: Total devastation. The stems of the main stem and tillers would rot about one inch from the soil surface _ the stems would fall over and any growth from affected stems would cease including head and grain development. The reason for this response is that fenoxaprop is translocated directly to and kills the growing point (nodes and developing head) in each stem after jointing begins.

    For wild oat control after the 6_leaf stage of wheat, some have petitioned the ND Dept of Ag to grant an emergency label for Achieve. Achieve (Zeneca) does not have a federal registration in any crop in the U.S. but is registered in Canada on wheat, durum, and barley for wild oat and foxtail control. Achieve is undergoing registration and should be available in 1999. Achieve is labeled from 2_leaf up to boot stage of small grains. Growers from at least the western part of the state have requested emergency labeling of Achieve for late season wild oat control. But, as mention above, Achieve is not presently labeled in ND nor in any other state.

    12. Herbicide drift, misapplication, and tank contamination continues to cause slight to severe crop injury and strains (sprains) neighborly relations. I frequently get asked for a list of analytical labs that can test for herbicide residues in soil and plant tissue. The following list is provided to help those who need qualitative sample analysis to help elucidate cause of plant injury.

 

LABORATORIES THAT ANALYZE FOR PESTICIDE RESIDUE

A & L Great Lakes Lab
3505 Conestoga Drive
Fort Wayne, IN 46808
(219) 483-4759 - Contact: Tim Grerer or Dan Kite
NOTE: Soil, water, and plant tissue samples.

Animal Disease Lab
9732 Shattuc Road
Centralia, IL 62801-5858
(618) 532-6701
NOTE: Soil, water, and plant tissue samples.

Columbia Labs
36740 East Old Historic Columbia River Highway
P.O. Box 40
Corbett, OR 97019
(503) 695-2287

Harris Laboratories
621 Rose Street
P.O. Box 80837
Lincoln, NE 68501
(402) 476-2811 - Contact: Joyce Pycha
NOTE: Only soil samples - NO plant tissue samples.

Hazelton Environmental Services
525 Science Drive
Madison, WI 53711
(608) 232-3300 - Contact: Peggy Popp
NOTE: Soil, water, and plant tissue samples.

Maxim Technologies
140 Telegraph Road
Middleport, NY 14105
(716) 735-3400
NOTE: Soil, water, and plant tissue samples.

Midwest Laboratories
13611 B Street
Omaha, NE 68144
(402) 334-7770 - Contact: Lisa Dworak
NOTE: Only soil and water samples - NO plant tissue samples.

Minnesota Valley Testing Laboratories, Inc.
326 Center Street
New Ulm, MN 56073
(507) 354-8517 - Contact: Anyone in customer service
NOTE: Soil and water samples - Plant tissue samples only for glyphosate.

Professional Service Industries
4820 West 15th Street
Lawrence, KS 66049
(800) 548-7901 - Contact: Sam Ferro
NOTE: Soil, water, and plant tissue samples.

Richard Zollinger
NDSU Extension Weed Specialist


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