NDSU Crop and Pest Report
Weeds


ISSUE 7  June 12, 2003

CONTROL OF VOLUNTEER ROUNDUP READY CANOLA IN ROUNDUP READY SOYBEAN

Several have asked how to control volunteer RUR canola in RUR soybean. A study was done last year (page 36, blue section of 2002 North Dakota Weed Control Research) where Harmony GT, Aim, FirstRate/Amplify, Flexstar, Raptor, and Extreme was applied at labeled and reduced rates to RUR canola 3 to 7 inches tall in RUR soybean. Harmony GT and Aim did not adequately control the canola at all rates applied. FirstRate/Amplify controlled the canola only at rates greater than 0.2 oz WDG/A. Flexstar, Raptor, and Extreme controlled the canola at all rate used.

Volunteer RUR canola control in RUR soybean.

 

Rate

RUR canola

 

prod/A

---- % ----

Harmony GT

0.083 oz

40

Aim

0.16 oz

22

FirstRate/Amplify

0.3 oz

96

FirstRate/Amplify

0.223 oz

92

FirstRate/Amplify

0.2 oz

90

FirstRate/Amplify

0.1 oz

72

Flexstar

0.75 pt

99

Flexstar

0.5 pt

99

Flexstar

0.375 pt

99

Raptor

2 fl oz

93

Raptor

1.5 fl oz

92

Raptor

1 fl oz

90

Extreme

2.235 pt

99

 

SLN LABEL ISSUED FOR HERBICIDE FOR KOCHIA IN WHEAT AND BARLEY FIELDS

A shortage of an effective herbicide to control late-stage kochia in North Dakota wheat and barley fields has prompted the ND DOA to issue a special local needs registration (SLN) to Dow AgroSciences for Vista.

Wet conditions this spring have allowed kochia and other weeds to reach relatively large sizes early in the season. Retailers are on short supply of Starane, the only registered herbicide effective against kochia in these later stages which merits the SLN registration.

Starane and Vista, both made by Dow, are similar formulas with the same amount of active ingredient. Vista® is currently registered for roadsides, rights-of-way and other non-crop areas, while Starane is registered for use on wheat, barley, oats, and similar crops.

This SLN will expire at the end of this year and is intended only to address the current shortage of Starane.

Applicators must follow all instructions, warnings and precautions on both the product and SLN labels and have a copy of the SLN label in their possession during application.

North Dakota leads the U.S. in barley production with 25 percent of the nation's supply and is second in overall wheat production, growing 13 percent of the nation's total.

 

HERBICIDE UPDATE - PART 4

Arrow (Makhteshim Agan North America (MANA)

Mode of action: ACCase inhibitor
a.i.: clethodim
Crops: various
Comments: Same active ingredient as Select. Registration expected in first quarter 2003.

Beyond (BASF)

Mode of action: ALS inhibitor
a.i.:
imazamox
Crops: Clearfield sunflower
Comments: Apply to Beyond at 4 fl oz/A to Clearfield sunflower from 2 to 8 inches in height. Clearfield varieties (Mycogen and Proseed) and seed quanties are limited in 2003. Adjuvants specified by label are limited to NIS + liquid nitrogen but use of oil adjuvants are not prohibited. Recommended to follow a Prowl soil application. Will not control ALS resistant kochia. The registration came 2 years earlier than anticipated. The accelerated registration came after the Health Effects Division of the EPA determined that the residues and dietary residues to imazamox, are not a toxicological concern. IR-4 requested that the EPA issue an exemption from tolerances for imazamox in all raw agricultural commodities.

Equip (Bayer)

Mode of action: ALS inhibitor
a.i.:
foramsulfuron + safener + iodosulfuron (30+2 DF)
Crops: Corn
Comments: Contains Option plus a long residual SU herbicide (iodosulfuron). Option, a short residual SU herbicide applied POST will control many grass and broadleaf weeds with no cropping rotation restrictions the following year. Iodosulfuron is a long residual herbicide. Apply Equip at 1.5 oz/A with an MSO type adjuvant + liquid fertilizer before corn is 12 inches tall. Equip will not control ALS resistant weeds. An 18 month rotation restriction is specified on the Equip label for many crops grown in ND.

Garlon 3A (Dow)

Uses: Aquatic
Comments: EPA approved use in aquatic environments. Excellent tool for purple loosestrife control. Garlon cannot be applied to moving water in streams and rivers but can be applied to marshes, wetlands, and on the banks of ponds and lakes. It can be applied to streams and rivers but overspray must be minimized to open water. This use is registered ONLY with the 3A formulation not Garlon 4. Garlon 3A is not a restricted use pesticide but applicators should check with the DNR to obtain a permit to treat aquatic areas. Grazing of treated areas is permitted but lactating dairy animals cannot graze until the fallowing season.

Gramoxone Max (Syngenta)

Uses: Dry pea, and potato desiccation.
Comments: ND labeling has changed Gramoxone Max rates for dry pea desiccation at 0.8 to 1.3 pt/A. Rates for potato desiccation is 0.7 to 1.3 pt/A.

Reflex (Syngenta)

Mode of action: PPO inhibitor
a.i.:
fomesafen
Crops: Dry bean
Comments: ND Section 18 registration has been approved allowing Reflex to be used on dry beans for broadleaf weed control, including waterhemp, common ragweed, and eastern black nightshade. See ND Weed Control Guide for rates and uses. Geographic area that Reflex can be used has been increased in 2003 and now includes all the following counties: Barnes, Benson, Bottineau, Burleigh, Cass, Cavalier, Dickey, Eddy, Foster, Grand Forks, Griggs, Kidder, LaMoure, McLean, Nelson, Oliver, Pembina, Pierce, Ramsey, Ransom, Richland, Sargent, Steele, Stutsman, Towner, Traill, Walsh, and Wells counties.

Apply at 0.75/A to weeds 1 to 4 inches tall with petroleum oil adjuvant at 0.5 to 1% v/v. Apply prior to dry bean bloom and before 30 days of harvest.

Richard Zollinger
NDSU Extension Weed Specialist
rzolling@ndsuext.nodak.edu


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