Efficacy of Preplant and Early Postemergence Herbicides in Corn

Kansas Agricultural Experiment Station Research Reports R. Currie 0 1 P. Geier 0 1 0 Kansas State University , USA 1 Kansas State University Agricultural Experiment Station and Cooperative Extension Service , USA Follow this and additional works at: https://newprairiepress.org/kaesrr Part of the Agronomy and Crop Sciences Commons, and the Weed Science Commons Recommended Citation Currie, R. and Geier, P. (2017) "Efficacy of Preplant and Early Postemergence Herbicides in Corn," Kansas Agricultural Experiment Station Research Reports: Vol. 3: Iss. 5. https://doi.org/10.4148/2378-5977.7413 - This report is brought to you for free and open access by New Prairie Press. It has been accepted for inclusion in Kansas Agricultural Experiment Station Research Reports by an authorized administrator of New Prairie Press. Copyright 2017 Kansas State University Agricultural Experiment Station and Cooperative Extension Service. Contents of this publication may be freely reproduced for educational purposes. All other rights reserved. Brand names appearing in this publication are for product identification purposes only. No endorsement is intended, nor is criticism implied of similar products not mentioned. K-State Research and Extension is an equal opportunity provider and employer. Creative Commons License This work is licensed under a Creative Commons Attribution 4.0 License. This weed science is available in Kansas Agricultural Experiment Station Research Reports: https://newprairiepress.org/kaesrr/vol3/iss5/31 Efficacy of Preplant and Early Postemergence Herbicides in Corn Summary A study was initiated near Garden City, KS, in 2016, comparing the weed control of several herbicide treatments applied sequentially for weed control in irrigated corn. Acuron (metolachlor + atrazine + mesotrione + bicyclopyrone), Clarity (dicamba), Corvus (isoxaflutole + thiencarbazone), Halex GT (metolachlor + glyphosate + mesotrione), and Lumax EZ (metolachlor + atrazine + mesotrione) were compared when combined at various ratios and timings. All combinations gave similar levels of weed control, allowing a producer to compare these tank mixes head-to-head based on prices alone. Introduction Acuron, Clarity, Corvus, Halex GT, and Lumax EZ are very competitive herbicides for weed control in corn. Therefore, it was the objective of this study to measure various combinations and times of applications of these products to allow economic comparisons. Experimental Procedures An experiment conducted at the Kansas State University Southwest Research-Extension Center near Garden City, KS, evaluated weed control with single and sequential herbicide treatments in corn. The entire plot area was over-seeded with foxtail, crabgrass, and Palmer amaranth, as well as the domestically cultivated sorghum ‘Rox orange’, quinoa and sunflowers. These serve as proxies for their wild relatives, shattercane, lambsquarters, and wild sunflowers, respectively. Single treatments were applied on May 23, 2016, which was 11 days prior to planting (11 DPP); sequential treatments consisted of 11 DPP treatments followed by early postemergence treatments applied on June 17, 2016. The early postemergence treatments were applied when corn had two true leaves (V2). All herbicides were applied using a tractor-mounted, compressed-CO2 sprayer delivering 20 GPA at 3.0 mph and 30 psi. Plots were 10- by 35-feet, and treatments were arranged in a randomized complete block with four replications. Soil was a Ulysses silt loam with 1.4% organic matter, pH of 8.0, and cation exchange capacity of 18.4. Visual weed control was determined on June 2 and August 18, 2016, which was 10 days after the preplant applications (10 DAPP) and 62 days after the early postemergence applications (62 DAPO), respectively. Corn yield was determined September 29, 2016, by mechanically harvesting the center two rows of each plot and adjusting grain weights to 15.5% moisture. Results and Discussion Quinoa and common sunflower control was 95 to 100% regardless of treatment or evaluation date (data not shown), while kochia control was 97% or more. At 62 DAPO, Palmer amaranth control was greater than 96% with all herbicides, except Corvus plus atrazine and glyphosate applied 11 DPP (93%). Green foxtail control was generally best (95 to 99%) when sequential herbicides were applied. Corn yields ranged from 138 to 167 bu/a and did not differ between any treatment (data not shown). All herbicide combinations gave similar levels of weed control, allowing producers to compare these tank mixes head-to-head based upon prices alone. Treatmenta Glyphosate AMS Acuron Atrazine Glyphosate AMS Acuron Atrazine Clarity 2,4-D ester Glyphosate AMS Acuron Atrazine Glyphosate AMS Halex GT Atrazine NIS AMS Acuron Atrazine Clarity 2,4-D ester Glyphosate AMS Halex GT Atrazine NIS AMS Acuron Atrazine Glyphosate AMS Acuron Atrazine Glyphosate AMS Rate per a 28 oz 2% 2.5 qt 0.4 qt 28 oz 2% 2.5 qt 0.4 qt 6 oz 6 oz 28 oz 2% 1.5 (...truncated)