Response of Glyphosate-Resistant Palmer Amaranth to Thirteen Residual Herbicides Jeremy Kichler
The Objective of this Study was to Determine The Most Effective Residual Herbicides for Use in Cotton 1. At planting 2. Postemergence 3. Layby
Two Locations in 2006 Macon County, Georgia Robeson County, North Carolina
Methods Plot Size – 6 feet by feet Conventional Tillage All herbicides applied to soil without debris
Planting Dates and Rainfall Planting/Application Dates May 1, 2006 – Macon County, GA May 24, 2006 – Robeson County, NC Factorial treatment 13 herbicides 2 herbicide rates 4 replications
Herbicide Treatments and 1X Rates Caparol (2 pt) Cotoran (2 pt) Direx (2 pt) Dual Magnum (1 pt) Envoke (0.1 oz) Layby Pro (2 pt) Linex (2 pt) Prowl H2O (2 pt) Reflex (1 pt) Stalwart (1 pt) Staple LX (1.7 oz) Suprend (1.0 lb) Valor SX (1.5 oz) All treatments were applied at 1X and 1.5X rates
Data Reporting Data from both GA and NC reported by location at two evaluation dates Rate main effect significant Herbicide treatment main effect significant
Percent Palmer Control Averaged Over Herbicide Treatments, DAT. RateGANC 1 X X9387 LSD23
RateGANC 1 X X8368 LSD45 Percent Palmer Control Averaged Over Herbicide Treatments, DAT.
Herbicide Options Caparol Cotoran Direx Prowl Reflex Staple Direx Layby Pro Linex Suprend Valor SX Dual Mag. Envoke Stalwart Staple At-PlantingPOSTLayby
LSD: GA = 6; NC = 6 *Data pooled over two rates. Percent Palmer Control by PRE Applied Residual Herbicides DAT.*
*Data pooled over rates. Palmer Amaranth Control by PRE Applied Residual Herbicides DAT.* LSD: GA = 10; NC =
Planting Dates and Rainfall Rainfall: GANC week 14.5 in0.4 in week 2-30 in2.99 in week 4-50 in2.08 in
Non-treated GA
115 ReflexStaple GA
ProwlCaparol GA
115 ReflexStaple NC
ProwlCaparol NC
*Data pooled over rates. Palmer Amaranth Control by POST Applied Residual Herbicides DAT.* LSD: GA = 6; NC =
*Data pooled over rates. Palmer Amaranth Control by POST Applied Residual Herbicides DAT.* LSD: GA = 10; NC =
StalwartDual Mag. GA
Palmer Amaranth Control by Layby Applied Residual Herbicides DAT.* *Data pooled over rates. LSD: GA = 6; NC =
Palmer Amaranth Control by Layby Applied Residual Herbicides DAT.* *Data pooled over rates. LSD: GA = 10; NC =
ValorDirex GA
Conclusions At-Planting Options -- Reflex or Staple Topical Options -- Staple or Dual Magnum Layby Directed Options -- Suprend or Valor
Conclusions Caution with Staple and Suprend due to growing occurrences of ALS inhibitor resistance. In fields without ALS resistance we recommend only 1 application of an ALS herbicide per season.