Life Sciences Commons^™

Fallow Weed Control With Vida Tank Mixtures, R. S. Currie, P. W. Geier

Kansas Agricultural Experiment Station Research Reports

The objective of the study was to compare Vida (pyraflufen) with various tank mix partners for glyphosate-resistant kochia control. Flixweed control was complete in fallow with all herbicides by 28 days after treatment. Kochia control was best when Vida was applied with glyphosate and Spartan. However, due in part to the extremely dry conditions, no treatment controlled kochia by more than 83% at 28 days after treatment, and kochia control began to decline after this 28 DAT.

Pixxaro Alone And In Combination For Weed Control In Fallow, R. S. Currie, P. W. Geier

Kansas Agricultural Experiment Station Research Reports

The objective of this study was to compare Pixxaro (halauxifen/fluroxypyr) alone and in combinations for weed control in fallow. Pixxaro alone was equal to or better than Banvel, Starane Ultra, or glyphosate alone for kochia control. However, the best kochia control occurred when these herbicides were mixed in various combinations. Similarly, Pixarro controlled flixweed equally as well as Banvel, Starane Ultra, or glyphosate at 7 days after treatment but flixweed control was complete regardless of herbicide later in the season.

Efficacy Of Imiflex, Zest, And Assure Ii On Green Foxtail Control, V. Kumar, I. Effertz, T. Lambert, R. Liu, B. Bean

Kansas Agricultural Experiment Station Research Reports

Grass weeds pose a serious management challenge in grain sorghum. Recent development of three herbicide-tolerant grain sorghum technologies such as Inzen, Igrowth, and DoubleTeam will provide the opportunity for producers to use nicosulfuron (Zest), imazamox (Imiflex), and quizalofop-p-ethyl (FirstAct) for grass weed control, respectively. The main objectives of this research were to (1) determine the effectiveness of Imiflex applied preemergence (PRE) on green foxtail control in comparison to commonly used group 15 herbicides; (2) compare the efficacy of Zest, Imiflex, and Assure II applied early- or late-POST at two different rates; and (3) determine the tank-mix compatibility of Zest, Imiflex, …

Zest Application Timings For Efficacy In Grain Sorghum, R. S. Currie, P. W. Geier

Kansas Agricultural Experiment Station Research Reports

This study was conducted to compare Zest (nicosulfuron) herbicide at two rates and two application timings for efficacy in grain sorghum. Palmer amaranth control was best when a preemergence (PRE) herbicide was followed by a late postemergence (LPOST) treatment. Zest at 0.67 or 1.33 oz/a provided the best velvetleaf and shattercane control. Either rate of Zest applied early postemergence (EPOST) controlled green foxtail more than 90%, but the higher rate was required for greater than 90% control when applications were delayed until LPOST.

Outlook Alone And In Mixtures For Efficacy In Corn, R. S. Currie, P. W. Geier

Kansas Agricultural Experiment Station Research Reports

The objective of the study was to compare Outlook (dimethenamid) alone and in various tank mixtures for season-long weed control in corn. Kochia control with most herbicides was 95% or more late in the season. However, Russian thistle control did not exceed 83% with any herbicide tested. Palmer amaranth control at 59 days after the postemergence treatments was similar among all herbicides, while green foxtail control was 93% or more with each treatment. All herbicides increased grain yields relative to the untreated control, but corn treated with Outlook or Verdict alone yielded less grain than the best yielding plots.

Foxtail Management In Smooth Brome Hay Meadows, S. R. Lancaster, S. R. Duncan

Kansas Agricultural Experiment Station Research Reports

Three different herbicides were applied at early bromegrass greenup and at post hay harvest to assess their effectiveness in controlling foxtail at two producer hay meadow sites in Pottawatomie (PT) and Dickinson (DK) counties. Pendimethalin applied early resulted in the greatest foxtail control, but control did not extend through the season to reduce late-summer infestations. Metsulfuron applied early resulted in approximately 30% visible brome injury. The injury was associated with 77 and 48% brome hay losses when compared to the untreated check, at the PT and DK sites, respectively. Injury from the early spring treatments was exacerbated by six freeze …

Impact And Liberty Rates And Mixtures For Efficacy In Corn, R. S. Currie, P. W. Geier

Kansas Agricultural Experiment Station Research Reports

The objective of the study was to compare Impact (topramezone), Liberty (glufosinate) and a premixture of the two herbicides (Sinate) for efficacy in corn. Rates for each herbicide were 0.75 and 1.0 oz/a for Impact, 22 and 30 oz/a for Liberty, and 21 and 28 oz/a for Sinate. Impact and Sinate, each at the high rates, and Status plus glyphosate provided the best kochia control for corn late in the season. These treatments, along with the low rate of Impact controlled crabgrass the best. Status was also the best treatment for Russian thistle, Palmer amaranth, and green foxtail control. The …

Novel Sorghum Herbicides For Grass Control In Fallow, R. S. Currie, P. W. Geier

Kansas Agricultural Experiment Station Research Reports

This study was conducted to compare herbicides for use in herbicide-tolerant grain sorghum for grass control in fallow. Imazamox applied preemergence (PRE) was generally the most effective herbicide regardless of weed species or evaluation date. Postemergence (POST) treatments did not control green foxtail more than 78% late in the season. Imazamox, Assure II (quizalofop), and Accent (nicosulfuron) applied PRE or early POST controlled shattercane and crabgrass 90% or more late in the season. Assure II applied late POST also controlled shattercane 93 to 95% late in the year.

Weed Control With Imazamox Rates And Timings In Herbicide-Tolerant Grain Sorghum, R. S. Currie, P. W. Geier

Kansas Agricultural Experiment Station Research Reports

The objective of this trial was to evaluate weed control and crop response using imazamox (KFD-365-02) in herbicide-resistant grain sorghum. Palmer amaranth control was 80% or less late in the season due to the herbicide-resistant weed biotype in the experiment. Both velvetleaf and shattercane control exceeded 90% with most herbicides late in the year. Using KFD-365-02 at the 9.0 oz/a rate applied preemergence alone or with atrazine or Moccasin II Plus controlled green foxtail and puncturevine the best. Most early postemergence treatments caused minor sorghum necrosis 6 days after treatments, but sorghum recovered fully within one week.

Effects Of Prescribed Fire Timing On Native Plant Composition, Forage Biomass Accumulation, And Root Carbohydrate Reserves In The Kansas Flint Hills: Year 2 Of 6, Z. M. Duncan, A. J. Tajchman, M. P. Ramirez, J. Lemmon, W. R. Hollenbeck, D. A. Blasi, K C. Olson

Kansas Agricultural Experiment Station Research Reports

Objective: The objective was to document the effects of prescribed fire timing on native plant composition, forage biomass, and root carbohydrate concentrations in key native tallgrass species in the Kansas Flint Hills.

Study Description: This experiment was conducted at the Kansas State University Beef Stocker Unit. Eighteen pastures were grouped by watershed and assigned to one of three prescribed-burn treatments: spring (April 7 ± 2.1 days), summer (August 21 ± 5.7 days), or fall (October 2 ± 9.9 days). Botanical composition, forage biomass, and root carbohydrate concentrations in big bluestem, little bluestem, Indian grass, and purple prairie clover were evaluated …

Fallow Weed Control With Liberty And Enlist One Tank Mixtures And Application Timings, R. S. Currie, P. W. Geier

Kansas Agricultural Experiment Station Research Reports

This study evaluated Liberty (glufosinate) and Enlist One (2,4-D choline) at three application timings and with various tank mix partners for weed control in fallow. Most herbicides tested controlled 94% or more of volunteer sorghum 17 days after the late postemergence treatments in the season. Conversely, Palmer amaranth and crabgrass control was less than 90% with most herbicides. However, control of these species was good when Tricor, or Zidua plus OpTill were applied preemergence followed by Liberty or Liberty and Enlist One late postemergence.

Auxinic Herbicide Mixtures For Controlling Multiple Herbicide-Resistant Kochia In Fallow, V. Kumar, T. Lambert, R. Liu, R. S. Currie, P. W. Stahlman

Kansas Agricultural Experiment Station Research Reports

Kochia resistant to glyphosate (Roundup), chlorsulfuron (Glean), and dicamba (Banvel or Clarity) has become quite common in the U.S. Great Plains, whereas multiple resistance to additional herbicides, including fluroxypyr (Starane Ultra), atrazine (AAtrex), and metribuzin (Sencor) has also been reported recently. Effective management of these multiple herbicide-resistant (MHR) kochia populations warrants the need of alternative herbicide strategies. The main objective of this research was to investigate the efficacy of auxinic herbicides, including Duplosan (dichlorprop-p), Weedone (2,4-D), Clash (dicamba), and/or Pixxaro (premix of halauxifen and fluroxypyr) alone or in various combinations for controlling MHR kochia. Separate greenhouse and field experiments were …

Control Of Volunteer Enlist Corn In Enlist E3 Soybean, R. Liu, I. Effertz, T. Lambert, V. Kumar

Kansas Agricultural Experiment Station Research Reports

Recent development of Enlist corn allows the use of 2,4-D choline (Enlist One), glyphosate (Roundup PowerMax), glufosinate (Liberty), and aryloxyphenoxypropionate (FOPs) herbicides for controlling grass and broadleaf weeds. However, volunteer Enlist corn plants can cause infestation in subsequent Enlist E3 soybean (resistant to 2,4-D, glyphosate, and glufosinate) in areas where a corn-soybean rotation is commonly practiced. The main objective of this research was to determine the effectiveness of cyclohexanedione (DIMs) herbicides alone or in tank-mixtures with Enlist One for Enlist corn control in Enlist E3 soybean. A field study was conducted in the 2020 growing season at the Kansas State …

Response Of Dicamba/Fluroxypyr/Glyphosate-Resistant Kochia To Atrazine And Alternative Postemergence Herbicides, R. Liu, V. Kumar, R. Currie, P. W. Geier, T. Lambert, P. W. Stahlman

Kansas Agricultural Experiment Station Research Reports

Two kochia accessions (KS-4A and KS-4H) were previously identified from a corn field near Garden City, KS, with multiple resistance to glyphosate (Roundup PowerMax), dicamba (Clarity), and fluroxypyr (Starane Ultra). The objectives of this research were to (1) determine the response of these kochia accessions to preemer­gence (PRE) and postemergence (POST) applied atrazine (Aatrex) in dose-response assays, and (2) determine the effectiveness of alternative POST herbicides. Seeds of a known susceptible kochia accession (SUS) collected from research fields in Hays, KS, were used for comparison. Greenhouse experiments were conducted at the Kansas State University Agricultural Research Center near Hays, KS, …

Response Of Kansas Feral Rye Populations To Aggressor Herbicide And Management In Coaxium Wheat Production System, V. Kumar, R. Liu, T. Lambert

Kansas Agricultural Experiment Station Research Reports

Feral rye (Secale cereale L.), also commonly known as cereal or volunteer rye, is a trou­blesome winter annual grass weed species in wheat producing regions of the United States, including Kansas. Lack of effective herbicide options complicates the selective control of feral rye in winter wheat. The main objectives of this research were (1) to determine the response of 10 feral rye populations collected from central Kansas wheat fields to Aggressor herbicide in dose-response assays, and (2) to evaluate the effective­ness of Aggressor herbicide for feral rye control in CoAXium winter wheat in Kansas. Dose-response assays indicated that all …

Early Postemergence And Sequential Herbicides For Weed Control In Corn, R. S. Currie, P. W. Geier

Kansas Agricultural Experiment Station Research Reports

In this study, herbicides were tested to compare sequential and split rates for weed control in corn. Control of green foxtail, Russian thistle, and quinoa was excellent regardless of herbicide treatment, and most herbicides provided good kochia and Palmer amaranth control. Minor corn injury occurred with some herbicides applied early postemergence or postemergence, but did not persist. All herbicide treatments increased grain yield 56 to 78% compared to the weedy control, but yields did not differ between herbicide treatments.

Residual Weed Control With Preemergence Herbicides In Grain Sorghum, R. S. Currie, P. W. Geier

Kansas Agricultural Experiment Station Research Reports

In this study, herbicides were tested to compare preemergence (PRE) application for weed control in grain herbicides. All herbicides controlled quinoa and crabgrass similarly, as well as Russian thistle late in the season. Halex GT at either rate with atrazine as well as Bicep Lite II Magnum controlled Palmer amaranth less than 90% late in the season. Similarly, these herbicides along with Degree Xtra provided less than 90% kochia control late. Grain yields did not differ between herbicide-treated and non-treated sorghum.

Efficacy Of Kfd-365-02 Rates And Mixtures In Imidazolinone-Tolerant Grain Sorghum, R. S. Currie, P. W. Geier

Kansas Agricultural Experiment Station Research Reports

This study compared various tank mixes of generic S-metolachlor/mesotrione and imazamox for weed control in imidazolinone-tolerant grain sorghum. All herbicides provided more than 90% control of Russian thistle, velvetleaf, and green foxtail, and kochia control late in the season was 85% or more. Puncturevine control late in the season was 80 to 90% with all herbicides except Coyote followed by KFD-365-02 and by KFD-365-02 at 6 oz/a plus atrazine followed by 2,4-D. Only Coyote followed by KFD-365-02 plus atrazine or 2,4-D controlled Palmer amaranth more than 78% late.

Single And Sequential Herbicide Treatments For Efficacy In Corn, R. S. Currie, P. W. Geier

Kansas Agricultural Experiment Station Research Reports

In this study, herbicides were tested to compare application of single and sequential treatments for weed control in corn. Quinoa and Russian thistle control was 95% or more regardless of herbicide treatment. Anthem Maxx, Resicore, and Corvus followed by Harness Max provided good control of Palmer amaranth. Acuron applied preemergence and Anthem Maxx plus Callisto and atrazine early postemergence were less effective on kochia than other herbicides, whereas Anthem Maxx plus Callisto and atrazine applied preemergence and Halex GT applied early postemergence were less effective on green foxtail. Grain yields from all herbicide-treated corn were substantially greater than for the …

Weed Management And Soybean Yields As Influenced By Row Width And Post-Emergent Herbicide Application Timing, S. R. Duncan, E. A. Adee

Kansas Agricultural Experiment Station Research Reports

Irrigated soybeans were grown in 2018 and 2019 at the Kansas River Valley Experi­ment Field near Rossville, KS. Soybeans were planted in 30-inch or 15-inch rows and a standard pre-emergent herbicide was applied. Planting dates were May 11 and June 4 in 2018 and 2019, respectively. The post-emergent herbicide was applied at approxi­mately 21 or 35 days following soybean planting (DAP). Weed control and crop injury were visually evaluated approximately every seven days following herbicide application. Yields, moisture, and test weights were calculated from the center two rows in 30-inch plots and four rows in 15-inch plots after combine harvest. …

Vida Tank Mixtures For Postemergence Weed Control In Fallow, R. S. Currie, P. W. Geier

Kansas Agricultural Experiment Station Research Reports

The objective of the study was to compare Vida (pyraflufen ethyl) with various tank mix partners for weed control in fallow. All herbicides controlled flixweed and tansymustard 96% or more by 16 days after treatment. Treatments containing Spartan provided faster and better kochia control compared to other herbicides, and these treatments were the only ones to control kochia 95% or more late in the season.

Control Of Multiple Herbicide-Resistant Palmer Amaranth In Enlist Corn, R. Liu, V. Kumar, T. Lambert

Kansas Agricultural Experiment Station Research Reports

Recent evolution of multiple herbicide resistant (MHR) Palmer amaranth [resistant to 2,4-D, glyphosate (Roundup), chlorsulfuron (Glean), atrazine (Aatrex), and mesotrione (Callisto)] is a serious threat to newly developed stacked trait technologies, including Enlist crops (tolerant to 2,4-D, glyphosate, and glufosinate). Field experiments were conducted in 2019 at the Kansas State University Agricultural Research Center near Hays, KS, to determine the effectiveness of various preemergence (PRE) followed by (fb) postemergence (POST) herbicides (multiple modes of action) for controlling this MHR Palmer amaranth in Enlist corn. The study was established in no-till dryland wheat stubble where MHR Palmer amaranth seeds …

Efficacy Of Late-Season Herbicide Programs For Controlling Palmer Amaranth In Postharvest Wheat Stubble, R. Liu, V. Kumar, N. Aquilina, T. Lambert

Kansas Agricultural Experiment Station Research Reports

Late-season control of Palmer amaranth in wheat stubble is a challenge for Kansas producers. The objective of this study was to determine the effectiveness of POST herbicide programs (with multiple modes of actions) for late-season control of Palmer amaranth in postharvest wheat stubble. The study was conducted at the Kansas State University Agricultural Research Center in Hays, KS, in 2019. The study site had a natural seedbank of Palmer amaranth that emerged immediately after wheat harvest. All selected herbicide programs were tested 3 weeks after wheat harvest, when Palmer amaranth plants had attained a height of 2 to 2.5 feet …

Comparison Of Terbuthylazine And Atrazine Preemergence In Grain Sorghum, R. S. Currie, P. W. Geier

Kansas Agricultural Experiment Station Research Reports

Terbuthylazine is an atrazine analog that is used in Europe as a replacement for atra­zine. This study compares terbuthylazine with common herbicide tank mixes for weed control in this region. All herbicides controlled quinoa and crabgrass 95% or more, whereas Bicep II Magnum controlled kochia, Palmer amaranth, and Russian thistle the best late in the season. No herbicide visibly injured grain sorghum in this experiment. Grain yields increased 18 to 32 bu/a when herbicides were applied compared to the nontreated controls except with atrazine at 24 oz/a.

Herbicide And Application Timing Effects On Windmillgrass (Chloris Verticillata) Control, Nicholas Mitchell, Jared Hoyle

Kansas Agricultural Experiment Station Research Reports

Windmillgrass (Chloris verticillata Nutt.) populations commonly infest turfgrass systems in the midwest, which result in aesthetically unacceptable turfgrass stands. Research trials were initiated in 2017 and 2018, in Onaga and Junction City, KS, to determine windmillgrass control with various single herbicide applications at dif­ferent application timings. Pylex (topramezone) resulted in more than 80% wind­millgrass control 8 weeks after spring and summer application.

Effects Of Spring-Planted Cover Crops On Weed Suppression And Winter Wheat Grain Yield In Western Kansas, A. K. Obour, J. D. Holman, J. A. Dille, V. Kumar

Kansas Agricultural Experiment Station Research Reports

Herbicide resistant (HR) weeds pose a major challenge to continuous no-tillage (NT) dryland crop management systems. Integrating cover crop (CCs) in dryland crop rota­tions could suppress weeds and provide a weed management option for HR weeds in NT systems. Field experiments were conducted to investigate weed suppression poten­tial of spring-planted CCs and their impacts on subsequent winter wheat grain yields. The CCs were oat/triticale, oat/triticale/pea, spring pea, and chem-fallow (standard) over 3 years and 2 locations in western Kansas. A weedy-fallow check was added to compare weed suppression of CCs in 2 out of the 3 years. Results showed CC …

Effective Herbicide Options For Controlling Glyphosate-Resistant Palmer Amaranth In Roundup Ready 2 Xtend Soybean, V. Kumar, R. Liu, T. Lambert, D. E. Peterson, C. L. Minihan, P. W. Stahlman

Kansas Agricultural Experiment Station Research Reports

Glyphosate-resistant (GR) Palmer amaranth has become a serious challenge for soybean producers in the mid-south and central United States, including Kansas. Field experi­ments were conducted at the Kansas State University Agricultural Research Center (KSU-ARC) near Hays, KS, and Kansas State University Ashland Bottoms (KSU-AB) research farm near Manhattan, KS, to determine the effectiveness of preemergence (PRE) and PRE followed by (fb) postemergence (POST) herbicide programs on GR Palmer amaranth control in Roundup Ready 2 Xtend soybean. The study site at Hays was infested with GR Palmer amaranth population prior to soybean planting; whereas, the Manhattan site had natural …

Characterization And Management Of Glyphosate- And Hppd-Inhibitor-Resistant Palmer Amaranth In Kansas Corn Production, V. Kumar, R. Liu, T. Lambert

Kansas Agricultural Experiment Station Research Reports

Multiple herbicide-resistant (MHR) Palmer amaranth is an increasing management concern for Kansas grain producers. The main purpose of this research was to 1) char­acterize the resistance levels to glyphosate (Roundup PowerMax) and mesotrione (Callisto) in an MHR Palmer amaranth population collected from Stafford County, KS, compared to a known herbicide-susceptible (SUS) population; and 2) to evaluate the effectiveness of preemergence (PRE), PRE followed by (fb) early post emergence (EPOST), and PRE fb late POST (LPOST) herbicide programs for controlling this MHR population in Roundup Ready and LibertyLink corn. To achieve these objec­tives, a whole plant dose-response study was …

Application Timing Efficacy Of Enlist Duo In Irrigated Corn, R. S. Currie, P. W. Geier

Kansas Agricultural Experiment Station Research Reports

In this study, herbicides were tested to compare application timing for weed control in irrigated corn. All herbicides tested provided season-long control (90% or more) of Palmer amaranth, Russian thistle, quinoa, and common sunflower. The inclusion of Enlist Duo to SureStart II as an early postemergence (V2) treatment increased kochia and johnsongrass control compared to a preemergence treatment of SureStart II alone early in the season. However, by later in the year, control of kochia and johnsongrass was best when Enlist Duo application was delayed until the V4 stage. Enlist Duo provided equal control of all weeds when applied at …

Efficacy Of Zest Application Timings In Irrigated Acetolactase Synthase-Resistant Grain Sorghum, R. S. Currie, P. W. Geier

Kansas Agricultural Experiment Station Research Reports

Acetolactase synthase inhibiting (ALS) herbicides were evaluated for efficacy in ALS-resistant grain sorghum. Kochia and quinoa control were similar among all herbicides tested regardless of evaluation date. Cinch ATZ alone preemergence, and Cinch plus Resolve and Harmony GT PRE followed by Zest POST controlled puncturevine 73-78%. Late-season green foxtail control was best when Zest was included as an early postemergence or postemergence application. Cinch ATZ applied alone preemergence, Cinch ATZ preemergence followed by Zest POST, and Cinch plus Resolve and Harmony GT PRE followed by Zest POST controlled Palmer amaranth 81–84%, and resulted in the highest grain yields.