2009 Corn Weed Control Update. Eric P. Prostko Extension Weed Specialist Dept. Crop & Soil Sciences UGA

Transcription

1 2009 Corn Weed Control Update Eric P. Prostko Extension Weed Specialist Dept. Crop & Soil Sciences UGA

2 Herbicide Resistance Concerns for Field Corn glyphosate ALS herbicides Accent, Basis Gold, Beacon, Exceed, Lightning, Option, Permit, Steadfast Atrazine

3 Glyphosate Resistance Around the World (15 species) rigid ryegrass (1996)** goosegrass (1997) horseweed (2000)** Italian ryegrass (2001)** hairy fleabane (2003)** buckhorn plantain (2003) common ragweed (2004)** giant ragweed (2004)** Palmer amaranth (2005)** common waterhemp (2005)** johnsongrass (2005)** wild poinsettia (2005) sourgrass (2006) junglerice (2007) liverseedgrass (2008) ** 9/15 (60%) can be found in the US

4 Georgia counties confirmed to be infested with glyphosate-resistant Palmer amaranth county counties counties counties 2008 screening in progress

5 GA Confirmed ALS-Resistant Palmer Sites

6 2008 Triazine Resistance Survey Macon County 4/20 sites resistant to 10X rate (4,5,15,20) 6/20 sites took 5 qts/a to kill (3,6,8,14,17,19)

7 A Closer Look (4, 5, 15, 20)

8 Site 5 Atrazine Resistance Survey Atrazine (qts/a)

9 Cotton Herbicides/Corn Rotations Cadre: 9 months Reflex Strongarm: 18 months Staple: 9-10 months Envoke: 210 days Staple Reflex: 10 months

10 Reflex Carryover in 2008 Early County

11 Burndown Control Options glyphosate paraquat Ignite (glufosinate) tank-mixes with? 2,4-D atrazine others Aim, ET, Harmony Extra (14 DBP), Express (14 DBP), Clarity, Valor (14 DBP) Need a clean seedbed at planting

12 Ryegrass Control - Burndown 1.50 lb ai/a = 35 oz/a of 5.5 lb/gal or 48 oz/a of 4 lb/gal 0.47 lb ai/a = 30 oz/a of 2L or 20 oz/a of 3L Hard to kill with 1 shot Ryegrass is most susceptible to glyphosate when applied between boot and early flower stage of growth. Option # lb ai/a + atrazine 3 pts/a Option # lb ai/a 2 WBP fb 0.47 lb ai/a + atrazine 3 pts/a at planting RR corn systems Accent????

13 Annual Ryegrass Control with Roundup WM oz/a 21 oz/a 42 oz/a 80 Control - % Late Tiller 2nd Node Boot Early Flower Stage of Growth Source: Lins et al Weed Technology 21:

14 Conventional or RR or LL Systems?

15 Conventional Systems Atrazine still THE major player in any system Prowl in cheap but. One of my favorites is Accent + Atrazine If Texas panicum is main problem many Pre-mixes

16 Accent + Atrazine 2008 (52 DAT) 96 Bu/A 148 Bu/A CN Ponder Farm June 13, 2008 NTC Accent 0.67 oz/a Atrazine 1.5 qt/a 1% v/v

17 Why do you not want to spend the money on an Accent + Atrazine treatment in field corn? Accent + Atrazine NTC Bu/A 163 Bu/A Data from 24 comparisons from field trials conducted in Georgia from At $3.00 to $4.00/bu, it only takes a 5-7 Bu/A increase to pay for the treatment!!!

18 Corn Yield Response to Various POST Herbicide Treatments Untreated Prowl Accent RR-split 250 Bu/A b 179 a 193 a 184 a 95 e 139 d 207 ab 212 a 0 low (11/ft2) Texas Panicum Density high (27/ft2) Average of 2 tests conducted in 2003 and 2004 (Tifton, Attapulgus) us) Where Texas panicum is the main weed problem Atrazine 1.5 qt/a

19 Conventional Weed Management Systems Many Pre-Mixes Available Bicep II Magnum (atrazine + Dual II Magnum) Lariat/Bullet (atrazine + Lasso) Lexar (atrazine + Dual Magnum + Callisto) many others preemergence a good choice if many different weed species are present need 0.5 of rainfall or irrigation within 7-10 days for activation

20 Macon County GR Palmer Amaranth June 24, DAP CN NTC Bicep II Magnum 2.1 qt/a PRE

21 Post-Directed Options for Field Corn Evik Gramoxone Inteon/Firestorm Lorox/Linex Aim tropical spiderwort pigweeds morningglory

22 U.S. Corn Acres Planted to Herbicide Resistant Hybrids % of Acres Year Source: NASS Includes stacked

23 Should you use the RR corn system? advantages easy Broad spectrum Reduced drift concerns No soil insecticide issues disadvantages No residual over-reliance on a single product Herbicide resistance concerns Volunteer in other RR crops Glyphosate price increases

24 How would I use RR corn systems? Must use atrazine or another residual 2 applications of glyphosate 1 st application: DAP + atrazine ( qt/a) 2 nd application: DAP Sequence (Dual Magnum + Touchdown) Expert (Dual Magnum + Atrazine + Touchdown) Halex GT (Callisto + Dual Magnum + Touchdown) Do not forget to include extra seed costs/a in your budgets! 30,000/A = $11.00/A 18,000/A = $7.00/A

25 Halex GT in Field Corn CN /19/ DAP Untreated Halex GT 4.39L 4 pt/a + NIS (POST)

26 Corn Grain Yield As Influenced by Glyphosate Timing (35 locations) % of Weed Time (DAP) Gower et al., Weed Technology 17:

27 Texas Panicum Control At Harvest with Single or Split Applications of Roundup WM - II Untreated CN (Attapulgus) Roundup 22 ozs/a 21 DAP Roundup 22 ozs/a DAP

28 Corn Yield Response to Single or Split Applications of glyphosate (4.5 lb 22 ozs/a Bu/A Untreated Single Split Average of 7 locations ( ) DKC67-60RR

29 Texas Panicum Control OR About 30% of the time, Accent has provided better control of Texas panicum But, yields have not been different.

30 What about Liberty-Link Link Corn? Glufosinate Liberty 1.67SL (30 oz/a) Ignite 2.34SL (22 oz/a) No tech fee up to 24 tall corn or V7 Tank-mix with atrazine Liberty ATZ good on morningglory, Texas millet, sicklepod Hybrid performance Garst 8353CB/LL, Hytest 7729Hx/LL, Pioneer 33M57

31 RR vs LL Corn CN /17/ DAP Untreated Roundup 22 oz/a 1.5 qt/a Prowl H pt/a (POST) Ignite oz/a 1.5 qt/a Prowl H pt/a 3 lb/a (POST)

32 Morningglory Control in Corn as much atrazine as possible 1.0 lb/a PRE fb 1.5 lb/a POST small grain rotations 2,4-D, Clarity, Status, Aim Liberty-Link Corn Systems split applications of glyphosate (RR corn) * 1 st application + atrazine Harvest Aids Aim or Sodium Chlorate

33 Pigweed Control in Corn preemergence Atrazine Dual/generics Outlook postemergence Atrazine Accent Callisto Laudis 2,4-D Permit Aim glyphosate (RR corn) Status Timing is critical!

34 100 Corn Yield Losses Caused by Palmer Amaranth Plants When They Emerge with Crop % Density (plants/meter) Massinga et al Weed Sci. 49:

35 This is what a 2 pigweed looks like!!!!

36 Macon County GR Palmer Amaranth June 24, DAP CN NTC Atrazine 1 qt/a PRE Atrazine 1.5 qt/a 30 DAP 1% v/v 30 DAP

37 GR-Palmer Amaranth Control in Field Corn July 24, 2008 (92 DAP) CN NTC Roundup PowerMax (22 oz/a) Atrazine (2 qt/a) Prowl H 2 0 (2.1 pt/a) EPOST (21 DAP)

38 Sicklepod Control in Corn Conventional Systems Atrazine 2,4-D Clarity Status Herbicide-Resistant RR corn system LL corn system

39 Nutsedge Control not very competitive 800 plants/100 row feet only reduce yields by 2% Eradicane or Sutan - PPI Dual II Magnum or generic PRE Glyphosate RR corn Split applications Basagran Permit

40 Tropical spiderwort (a.k.a. Benghal dayflower) Commelina benghalensis tropical Africa native annual or perennial seeds and rhizomes above and below ground flowers 1,600 seeds/plant alternate host of southern root-knot nematode Reservoir for southern stem blight (white mold)

41 TSW in Georgia 2004: 29 counties (light blue) 2005: 5 counties (black) 2006: 6 counties (dark blue) 2007: 2 counties (yellow) 2008: 2 counties (red)

42 TSW Control in Field Corn Depends on planting date 2,4-D or Aim POST Sequence or Expert in RR corn Aim/Gramoxone/Evik + Dual Magnum layby Post-harvest may be more important than in-crop Tillage 2 applications of 2,4-D, Gramoxone, or Aim

43 Tropical Spiderwort Control in Field Corn Untreated Aim 1.5 ozs/a Dual Magnum 1.33 pt/a 1% v/v 34 DAT CN

44 Post-Harvest Control of Tropical Spiderwort POST1: 8-10 tall COMBE POST2: 2 weeks later Photo 1 week after POST2 Untreated 1.5 pt/a POST1 + POST 2 ($14.41/A)

45 Johnsongrass Control in Corn Accent no OP soil insecticide hybrid tolerance to Accent hybrid resistance to MDMV Glyphosate in RR corn

46 Callisto New (er( er) ) Products Status Resolve Q Laudis Generic Accent s

47 Syngenta POST 3 oz/a + COC + UAN or AMS ($12-13/A) Up to 30 tall or 8-leaf corn Palmer amaranth up to 5 Tank-mix with atrazine also good on horsenettle Interaction with OP s Weak on PANTE and CASOB Good option for atrazine, ALS and GR-Palmer Unique mode of action Bleacher

48 Callisto + Atrazine 2008 (51 DAT) CN /13/08 NTC Callisto 3 oz/a Atrazine 2 qt/a 1% v/v

49 BASF Status 56WG dicamba + diflufenzopyr + isoxadifen Super Banvel + safener POST 5-10 oz/a ($2.20/oz) broadleaf weed control

50 GR-Palmer Amaranth Control in Field Corn July 24, 2008 (92 DAP) CN NTC Status 5 oz/a 0.25% v/v 3 lb/a EPOST (21 DAP)

51 Dupont Resolve Q Resolve (rimsulfuron) + Harmony (thifensulfuron) + safener (isoxadifen) 1.25 oz/a + COC or NIS + N POST control but has some residual 20 corn or 7 collars Is it as good as Accent on Texas millet in GA????????

52 Accent vs. Resolve Q (51 DAT) NTC Accent 0.67 oz/a Atrazine 1.5 qt/a 1% v/v Resolve 1.25 oz/a Atrazine 1.5 qt/a 1% v/v CN Ponder Farm June 13, 2008

53 Laudis 3.5SC Bayer Tembotrione + isoxadifen (safener) Bleacher POST 3 oz/a Emergence to V8 stage Requires use of MSO and nitrogen Good for pigweed management Also has crabgrass and BL signalgrass listed on label Is it as good as Accent on Texas millet?

54 Laudis vs. Accent CN Attapulgus Farm June 12, DAT NTC Laudis 3 oz/a Atrazine 1.5 qt/a 1% v/v 1.5 qt/a Accent 0.67oz/A 2 qt/a 1% v/v

55 Generic Accent s (nicosulfuron) NIC-IT Cheminova Formulated as 2SC instead of 75WDG Use rate is 2 oz/a Samson UPI 0.33 ai/gal (SC) Use rate is 12 oz/a Both have not yet been tested in GA

56 Optimum GAT Technology Glyphosate-ALS Tolerance Dupont/Pioneer Glyphosate metabolic inactivation mechanism Gene shuffling Insensitive ALS enzyme Soybean 2009/ demonstration plots Commercial introduction Field corn (2010?) What does it bring to the table? Flexibility

57 Optimum GAT Field Corn CN /13/ DAT NTC Touchdown Total - 24 oz/a Classic oz/a Harmony GT 0.25 oz/a Express oz/a Callisto 2.5 oz/a All applied at V3 stage

58 Potential GAT Corn Products Diligent Classic + Resolve + Valor Freestyle Classic + Harmony + Express Instigate Classic + Resolve + Callisto Traverse Classic + Resolve Trigate Resolve + Express + Callisto

59 For More Weed Science Info