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2017 Field Corn Weed Management Update
AUTHOR
Eric P. Prostko
Professor and Extension Weed Specialist
University of Georgia
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TABLE OF CONTENTS
2017 Field Corn Weed Management Update
Field Corn Yield Loss (%) Caused by Uncontrolled Weeds in Georgia Weed Science Research Trials (2007-2016)
Timing of Herbicide Application- DAP or GDD?
Later POST Applications?
Atrazine + Any of these works just fine!
Weed Control in Field Corn - 2016
Weed Control in Field Corn - 2016
Weed Control in Field Corn - 2016
Anthem, Dual, Warrant, Zidua????
Palmer Amaranth Control with Zidua, Dual Magnum, and Warrant Applied PRE to Bare-Ground - 2016
PRE Zidua or Dual on Texas Panicum
Zidua on Texas Millet?
Evik or Not?
What can you use in field corn if you have resistance to glyphosate, atrazine, and/or ALS herbicides?
Weed Control in Field Corn Without Atrazine or Glyphsoate
Field Corn Injury - Status
Revulin Q
Weed Control with Revulin Q - 2016
Something to think about?
Herbicides and High Yield Corn
Herbicide Effects on Field Corn Yield in a High Input Environment
Roundup P-Max (32 oz/A) + Atrazine (48 oz/A) + AMS Xtra (2.5% v/v) Timing Effects on Field Corn Yield in a High Input Environment - YEAR 3
Pay Closer Attention to Hybrid/Herbicide Mgt. Guidelines
ALS-Sensitive Field Corn Hybrids
Can ALS herbicide formulations that contain a crop safener (isoxadifen) be used on ALS sensitive corn hybrids?
ALS-Sensitive Field Corn Yield as Influenced by POST Herbicide Treatment in Georgia (2014-2015)**
What happens when you spray Liberty on a non-LL corn hybrid?
Roundup + Atrazine + AMS + MgSO4
Question/Comments
SLIDE CONTENTS
Eric P. Prostko Professor/Extension Weed Specialist Dept. Crop & Soil Sciences 2017 Field Corn Weed Management Update
Figure 1. Field Corn Yield Loss (%) Caused by Uncontrolled Weeds in Georgia Weed Science Research Trials (2007-2016). Treated vs. Non-treated 225 * 0.38 * 4.00 = $342/A
Timing of Herbicide Application DAP or GDD? *Assumes crop emergence on March 25 (5 DAP) V1.8 V2.7
Later POST Applications? V6 stage all leaves are initiated Ear shoot initiation Kernel rows/ear begins Tassel initiation Growing point above soil surface ~500 GDD
Atrazine + Any of these works just fine!
Weed Control in Field Corn - 2016 CN-01B-16 May 4 44 DAP NTC Dual II Magnum 7.62EC @ 16 oz/A (PRE) Roundup P-Max 5.5SL @ 32 oz/A (29 DAP) Atrazine 4L @ 64 oz/A (29 DAP) 165 Bu/A (4 rep avg.) 220 Bu/A (4 rep avg.)
Weed Control in Field Corn - 2016 CN-01B-16 May 4 44 DAP NTC Dual II Magnum 7.62EC @ 16 oz/A (PRE) Laudis 3.5SC @ 3 oz/A (29 DAP) Atrazine 4L @ 64 oz/A (29 DAP) MSO @ 1% v/v (29 DAP) 165 Bu/A (4 rep avg.) 249 Bu/A (4 rep avg.)
Weed Control in Field Corn - 2016 CN-01-16 May 16 35 DAP NTC Dual II Magnum 7.62EC @ 16 oz/A (PRE) Halex GT 4.39SC @ 58 oz/A (21 DAP) Atrazine 4L @ 32 oz/A (21 DAP) COC @ 1% v/v (21 DAP)
Anthem, Dual, Warrant, Zidua????
Palmer Amaranth Control with Zidua, Dual Magnum, and Warrant Applied PRE to Bare-Ground - 2016 Time (DAT) Control (%) NC-01-16
PRE Zidua or Dual on Texas Panicum Zidua 85WG @ 1.5 oz/A Dual II Magnum 7.62EC – 21 oz/A CN-10-16 May 16 35 DAT
Zidua on Texas Millet? CN-10-16 May 16 Zidua 85WG @ 1.5 oz/A – PRE Photo 35 DAT Plot# 316
Evik or Not? CN-01-16 July 7 108 DAP NTC Atrazine 4L @ 32 oz/A (PRE) Roundup P-Max 5.5SL @ 32 oz/A (POST) Atrazine 4L @ 48 oz/A (POST) Atrazine 4L @ 32 oz/A (PRE) Roundup P-Max 5.5SL @ 32 oz/A (POST) Atrazine 4L @ 48 oz/A (POST) Evik 80DG @ 2 lbs/A (PDIR) NIS @ 0.25% v/v (PDIR)
What can you use in field corn if you have resistance to glyphosate, atrazine, and/or ALS herbicides? Residuals Zidua Dual Magnum Warrant Postemergence* Liberty Status Revulin Q Impact/Armezon Laudis Capreno Halex GT 2,4-D * double-crop soybean rotations?
Weed Control in Field Corn Without Atrazine or Glyphsoate CN-10-16 June 3 53 DAP NTC Dual II Magnum 7.64EC @ 21 oz/A (PRE) Laudis 3.5SC @ 3 oz/A (POST) COC @ 1% v/v (POST) AMS Xtra @ 2.5% v/v (POST) Warrant 3ME @ 48 oz/A (PRE) Impact 2.8L @ 1.0 oz/A (POST) COC @ 1% v/v (POST) AMS Xtra @ 2.5% v/v (POST)
Field Corn Injury - Status Status dicamba-NA + diflufenzopyr + isoxadifen CN-04-16 Agrigold 6659 7 DAT (April 25, 2016) Roundup P-Max @ 32 oz/A + Status @ 5 oz/A
Revulin Q DuPont Accent + Callisto + isoxadifen (safener) MOA = 2 + 27 EPOST (20” tall or V6) 3.4-4.0 oz/A Tank mix with atrazine Cotton or soybean = 10 months; peanut = 18 months; small grains = 4 months No Counter INFR
Weed Control with Revulin Q - 2016 CN-09-16 June 3 53 DAP NTC Revulin Q 51.2WG @ 3.4 oz/A Atrazine 4L @ 64 oz/A COC @ 1% v/v AMS Xtra @ 2.5% v/v Applied 17 DAP
Something to think about? Some GA growers are pushing yield limits (250+ Bu/A) 75%-80% irrigated At lower yield/input levels, are herbicide stresses masked by other stresses? At higher yield/input levels (i.e. most stresses are controlled), what about herbicides?
Herbicides and High Yield Corn After 3 years of testing under weed-free condtions…….. various herbicides applied at recommended time (V2-V5) did not reduce corn yields. glyphosate + atrazine applied from V2 to V8 did not reduce corn yields.
Herbicide Effects on Field Corn Yield in a High Input Environment (RU = Roundup W-Max, ATZ = Atrazine, PW = Prowl, LIB = Liberty, STDQ = Steadfast Q, CAP = Capreno, LAD = Laudis, HGT = Halex GT, SAN = Sandea) – Average of 3 years (2014 + 2015 + 2016) Applied 17 -27 DAP ~V2-V5 STAGE (178-337 GDD) Weed-free Dowdy Farms (Brooks Co.) BC A ABC C C AB C C Pairwise t-tests: LS Means P= 0.10
Roundup P-Max (32 oz/A) + Atrazine (48 oz/A) + AMS Xtra (2.5% v/v) Timing Effects on Field Corn Yield in a High Input Environment – YEAR 3 CN-05-16 Agrigold 6659 P = 0.5029 CV = 7.57
Pay Closer Attention to Hybrid/Herbicide Mgt. Guidelines
ALS-Sensitive Field Corn Hybrids Dekalb WARNINGS DKC 62-05 DKC 62-06 DKC 62-08 DKC 63-44 DKC 63-47 DKC 63-55 DKC 64-69 CAUTIONS 65-17, 65-18, 65-20 70-01, 70-03 RX940, RX940RR2 Pioneer WARNINGS P1324HR P1360 P1360AM P1360CHR P1360HR P1739R P1739YR CAUTIONS P1637R, P1637VYHR, P1637YHR P1690,P1690HR, P1690R P2088R, P2089YHR
Can ALS herbicide formulations that contain a crop safener (isoxadifen) be used on ALS sensitive corn hybrids? Steadfast Q = nicosulfuron + rimsulfuron + isoxadifen Resolve Q = rimsulfuron + thifensulfuron + isoxadifen Realm Q = mesotrione + rimsulfuron + isoxadifen Accent Q = nicosulfuron + isoxadifen Revulin Q = mesotrione + nicosulfuron + isoxadifen Capreno = tembotrione + thiencarbazone + isoxadifen
ALS-Sensitive Field Corn Yield as Influenced by POST Herbicide Treatment in Georgia (2014-2015)** **Averaged over 2 years (2014-2015) and 2 corn hybrids (DKC 64-69 and DKC 62-08) Al treatments also included atrazine @ 2 lb ai/A + COC @ 1% v/v. Weed-free A ABC AB BC C BC C a= 0.10
What happens when you spray Liberty on a non-LL corn hybrid? CN-01B-16 DKC 66-59 Liberty @ 29 oz/A + Atrazine @ 48 oz/A 6 DAT (April 25, 2016) Still made 28 Bu/A!!!!!
Roundup + Atrazine + AMS + MgSO4 NTC Roundup P-MAX 5.5SL @ 22 oz/A Atrazine 4L @ 64 oz/A AMS Xtra @ 2.5% v/v Roundup P-MAX 5.5SL @ 22 oz/A Atrazine 4L @ 64 oz/A AMS Xtra @ 2.5% v/v MgSO4 @ 4 lb/A CN-13-16 May 4, 2016 14 DAT
Question/Comments