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Lessons Learned (or not) in 2007. Eric P. Prostko Extension Weed Specialist Dept. of Crop & Soil Sciences. Topics For Discussion. Weather Drought, freeze, heat Problems Triazine resistance Corn rotations (Reflex, Staple) Provost contaminated 2,4-DB Mixing errors
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Lessons Learned (or not) in 2007 Eric P. Prostko Extension Weed Specialist Dept. of Crop & Soil Sciences
Topics For Discussion • Weather • Drought, freeze, heat • Problems • Triazine resistance • Corn rotations (Reflex, Staple) • Provost • contaminated 2,4-DB • Mixing errors • RR cotton in RR soybeans • Will we be able to handle Palmer amaranth? • A new herbicide?
March-April-May Rainfall in Georgia (2007) - 5.58 -11.31 -9.59 Source: GEMN
April 8, 2007 Georgia FreezeMinimum Temperatures Source: GEMN
Maximum Air Temperatures in Georgia (August 4 – August 15, 2007) Source: GEMN
Triazine Resistant Palmer AmaranthMacon County 2007 • Atrazine 4L @ 1 qt/A (PRE) fb Atrazine 4L @ 1.5 qt/A + COC @1% v/v (POST) • Photo 14 Days after POST • 15-20 year rotation • Ryegrass-corn-sorghum-sudangrass
Cotton Herbicides/Corn Rotations Reflex • Staple: 9-10 months • Envoke: 210 days • Reflex: 10 months Staple
Field Corn Yield Response to PRE Applications of Reflex 2SC - 2007 a a a a a a a a a a a a a a a a Bu/A b a b c c Average field half-life of Reflex is 100 days. Label restriction for corn is 10 months!
PRE- Reflex 2L Injury to Corn 9 DAT NTC 16 oz/A 4 oz/A 8 oz/A 0.5 oz/A 2 oz/A 1 oz/A
Provost (10.7 oz/A) + Fulbor + Penatrator Plus + 2,4-DB Richard McDaniel, 2007
Lot #’s EC-16 FB-01
Be careful when mixing!! Staple, Envoke, Cadre are not a good idea on soybeans!!!!
Controlling RR Cotton in RR Soybeans • Preemergence • Canopy 75DG (8 oz/A) • Sencor 4L (8-12 oz/A) • Sencor 75DF (5.3-8 oz/A) • POST glyphosate tank-mixes • 6” cotton, 3 leaves • Resource (4 ozs/A) - 77% • 2,4-DB (2 ozs/A) - 76% • Reflex (12 ozs/A) - 72% • Classic (0.33 ozs/A) - 62% • PRE only = 54-87% • POST only = 62-77% • PRE + POST = > 95% Source: York et al., Weed Technology. 2004. 532-539.
Managing Palmer Amaranth • Know your enemy • Resistant or not?? • ALS or GR • Residual herbicide • activation • Timely POST’s • Avoid overusing PPO’s
GR-Palmer Amaranth Control in Soybean – 2007 (83 DAT) Untreated Prefix 5.2EC @ 2.03 pt/A SB-01-07
Palmer Amaranth Control in PeanutsMacon County, GA – 2007 (38 DAT) NTC Valor SX 51WG @ 3 oz/A
GR-Palmer Amaranth Control in Field CornMay 31, 2007 (38 DAP) Roundup Original Max (22 oz/A) Atrazine (2 qt/A) Prowl H20 (2.1 pt/A) EPOST (18 DAP) NTC CN-07-07
Palmer Amaranth Control in Sorghum-Sudangrass Silage NTC 2,4-D amine @ 1 pt/A (27 DAT) GS-01-07
A New Herbicide • KIH-485 (pyroxasulfone) • Kumiai • corn and soybeans • GA tests on peanuts and cotton • MOA not well understood at this time • Shoot inhibitor???? • Similar to metolachlor?? • Used at lower rates • more active on Texas panicum
Texas Panicum Control in Field Corn with KIH-485 Applied PRE (53 DAT) NTC KIH-485 85WG @ 4.2 oz/A (0.223 lb ai/A)
Wild Radish Control in Field Corn with KIH-485 Applied PRE (43 DAT) KIH-485 85WG @ 1.67 oz/A (0.089 lb ai/A) NTC
Tropical Spiderwort Control in Peanuts with KIH-485 (2007) – 15 DAT NTC Gramoxone Inteon @ 12 oz/A KIH-485 @ 4.2 oz/A Storm @ 12 oz/A 80/20 @ 0.25% v/v NTC PE-10-07