Life Sciences Commons^™

Liberty Rates And Tank Mixes With Balance Flexx, Capreno, Diflexx, Halex Gt, And Laudis For Weed Control In Irrigated Liberty-Resistant Corn, R. S. Currie, P. W. Geier

Kansas Agricultural Experiment Station Research Reports

Control of common sunflower, quinoa, green foxtail, and kochia was excellent regardless of herbicide treatment or evaluation date. Palmer amaranth and crabgrass control was 95% or more regardless of herbicide treatment at 7 days after postemergence application (DAPT). Postemergence applications of Liberty (glufosinate) at any rate alone controlled Palmer amaranth greater than 85% 72 DAPT, whereas tank mixing any herbicide with Liberty increased control 7 to 15%. Crabgrass control was greater than 89% at 72 DAPT with all treatments except when Liberty at 22 oz/a was applied with Diflexx (dicamba). Corn yields did not differ among herbicide-treated plots, but all …

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

Kansas Agricultural Experiment Station Research Reports

Kochia control at soon after application was best when Vida (pyraflufen) was tank mixed with glyphosate, 2,4-D amine, and/or dicamba. However, no Vida treatment controlled kochia more than 60% one month after treatment. Treatments containing glyphosate, 2,4-D, and/or dicamba without Vida did not control kochia more than 33% during the first month. Similarly, Russian thistle control was best regardless of evaluation date when Vida was applied alone or tank mixed with another herbicide. Vida treatments provided 90 to 94% Russian thistle control one month after treatment. Treatments without Vida controlled Russian thistle no more than 63%.

Comprehensive Control Of Sericea Lespedeza With Four Consecutive Years Of Prescribed Fire During Summer, J. A. Alexander, W. H. Fick, J. Lemmon, G. A. Gatson, K C. Olson

Kansas Agricultural Experiment Station Research Reports

Objective: The objective of this study was to evaluate the effects of annual prescribed burning applied during the growing season on vigor of sericea lespedeza (Lespedeza cuneata) infesting native tallgrass range.

Study Description: We burned nine fire-management units (14 ± 6 acres) at one of three prescribed-burning times: early spring (April 1), mid-summer (August 1), or late summer (September 1). Effects on sericea lespedeza were evaluated annually on July 10, October 10, and November 1.

The Bottom Line: Compared to traditional spring, dormant-season burning, burning during the summer months over four consecutive years resulted in …

Grazing Diets Of Mature Ewes In The Flint Hills Contain A Significant Proportion Of Sericea Lespedeza, C. A. Sowers, J. D. Wolf, W. H. Fick, K C. Olson

Kansas Agricultural Experiment Station Research Reports

Objective: The objective of this study was to characterize diets selected by sheep grazing sericea lespedeza (Lespedeza cuneata) infested native tallgrass pastures and contrast these diets to those of cattle grazing the same range earlier in the grazing season. Multi-species grazing may provide an additional tool to aid landholders in the control of sericea lespedeza compared to cattle grazing only.

Study Description: The study was conducted on 8 native tallgrass pastures grazed by more than 800 mature ewes. Pastures were infested with sericea lespedeza (basal frequency = 2.9 ± 2.43%) and stocked with yearling steers at a relatively …

Cattlemen's Day 2018, E. A. Boyle

Kansas Agricultural Experiment Station Research Reports

Full report, Cattlemen's Day 2018.

Herbicide And Application Timing Effects On Windmillgrass 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 in Onaga and Junction City, KS, to determine windmillgrass control with various single herbicide applications at multiple application timings (spring, summer, and fall). Data collection for research trials consisted of visual percent windmillgrass cover (0–100%), line intersect analysis on four-inch spacing, normalized difference vegetation index (NDVI) (0 to 1 scale), and windmillgrass seedhead counts. Initial observations resulted in greater windmillgrass control with summer applications compared to fall applications. Pylex (topramezome) resulted in 80% windmillgrass …

Dicamba-Tolerant Volunteer Soybean, Palmer Amaranth, And Green Foxtail Control In Irrigated Field Corn, R. S. Currie, P. W. Geier

Kansas Agricultural Experiment Station Research Reports

Dicamba-tolerant soybean control was best when Armezon (topramezone) or Armezon Pro (topramezone + dimethenamid) was applied POST with atrazine and glyphosate, and when Status (dicamba + diflufenzopyr), atrazine, and glyphosate were applied POST. These treatments, along with PRE treatments of Armezon Pro and atrazine, completely controlled soybean. Similarly, control of Palmer amaranth and green foxtail was generally best with Armezon Pro and atrazine applied PRE or any herbicide combination applied POST. Corn receiving PRE treatments yielded 41 to 120 bu/a more grain than the weedy checks, whereas corn treated POST yielded 117 to 145 bu/a more grain than the untreated …

Vida Alone And In Tank Mixtures For Spring Kochia Control In Fallow, R. S. Currie, P. W. Geier, G. W. Boyer, P. W. Stahlman

Kansas Agricultural Experiment Station Research Reports

No herbicide treatment provided more than 50% kochia control at Garden City, KS, or 80% kochia control at Hays after the first week of application. At Garden City, KS, treatments of Vida (pyraflufen) plus glyphosate and 2,4-D or dicamba, glyphosate alone, or glyphosate plus 2,4-D or dicamba provided greater than 89% kochia control. At Hays, glyphosate alone or with 2,4-D, and Vida plus dicamba alone or with glyphosate had greater than 85% control of kochia.

Late Summer Prescribed Fire And Fall Herbicide Application Show Strong Suppressive Effects On Sericea Lespedeza Frequency And Vigor, G. A. Gatson, W. H. Fick, W. W. Hsu, K C. Olson

Kansas Agricultural Experiment Station Research Reports

Objective: The objective of this study was to evaluate the efficacy of a one-time application of late summer prescribed fire followed by fall herbicide application for substantially reducing sericea lespedeza frequency and vigor.

Study Description: A single 80-acre native tallgrass pasture was divided into 16 units. Each of these units was either burned in early September (burn only), sprayed with Escort XP (DuPont, Wilmington, DE) in late September (spray only), burned in early September and subsequently sprayed in late September (burn + spray), or neither burned nor sprayed (control). Sericea lespedeza frequency and vigor was measured shortly before …

Naive Yearling Steers Consume Little Sericea Lespedeza In The Kansas Flint Hills, C. A. Sowers, J. D. Wolf, W. H. Fick, K C. Olson

Kansas Agricultural Experiment Station Research Reports

Objective: The objective of this study was to characterize diets selected by steers grazing sericea lespedeza (Lespedeza cuneata)-infested native tallgrass pastures.

Study Description: The experiment was conducted on eight native tallgrass pastures located in Woodson County, KS, at the Kansas State University Bessner Range Research Unit during the 2015 and 2016 growing season. Pastures were burned annually in April and stocked with yearling steers (n = 281/year; initial body weight = 582 ± 75 lb) at a relatively high stocking rate (2.7 acres/steer) from April 15 to July 15. Basal frequency of sericea lespedeza was 2.9 …

Efficacy Of Mesotrione-Based Tank Mixtures And Application Timings Compared To Standards In Irrigated Corn, R. S. Currie, P. W. Geier

Kansas Agricultural Experiment Station Research Reports

Kochia, Russian thistle, and quinoa control was excellent regardless of treatment or rating date. Sunflower control at 10 DAPT was very good when Anthem Maxx (pyroxasulfone + fluthiacet) + Solstice (fluthiacet + mesotrione) + atrazine and glyphosate were applied EPOST, while green foxtail control was 94% with the same treatment at 68 DAPT. Palmer amaranth and green foxtail control at 68 DAPT was 93 and 91%, respectively, when SureStart II (acetochlor + flumetsulam + clopyralid) + atrazine and glyphosate were applied PRE followed by glyphosate POST. All herbicide-treated corn yielded 34 to 69 bu/a more grain than the untreated control. …

Diflexx Duo Compared To Capreno, Halex Gt, Armezon, Outlook, Status, Degree Xtra, And Bicep Ii Magnum For Weed Control In Irrigated Corn, R. S. Currie, P. W. Geier

Kansas Agricultural Experiment Station Research Reports

Control of kochia, quinoa, and green foxtail was complete with all herbicides at 78 days after treatment (DAT). Palmer amaranth, common sunflower, and crabgrass was 97% at 8 DAT. By 78 DAT, common sunflower control was complete with all herbicides. Crabgrass control at 78 DAT was excellent except when Diflexx Duo (dicamba + tembotrione) at 24 oz/a + atrazine was mixed with glyphosate or Liberty. All herbicide-treated corn yielded 111 to 126 bu/a more grain than the untreated controls. The various additions to the premixes improved weed control to the point that no difference occurred among them for yield.

Split Applications Of Acuron, Halex Gt, Resicore, Balance Flexx, And Armezon Pro For Weed Control In Irrigated Corn, R. S. Currie, P. W. Geier

Kansas Agricultural Experiment Station Research Reports

Control of kochia, green foxtail, quinoa, and Palmer amaranth was excellent and did not differ among treatments. Common sunflower control was slightly less effective with Acuron (S-metolachlor + atrazine + mesotrione + bicyclopyrone) + atrazine applied PRE compared to other treatments early in the season but later in the season no differences occurred. Crabgrass control was excellent regardless of treatment early in the season, and remained high with all herbicides except Balance Flexx (isoxaflutole) + atrazine PRE followed by Diflexx (dicamba) + atrazine and glyphosate POST, which provided less than 89% control. All herbicide treatments resulted in grain yields that …

Sericea Lespedeza Control From Growing-Season Prescribed Burning Causes No Collateral Damage To Non-Target Species, J. A. Alexander, W. H. Fick, J. Lemmon, G. A. Gatson, K C. Olson

Kansas Agricultural Experiment Station Research Reports

Objective: The objective of this study was to evaluate the effects of 4 consecutive years of prescribed fire applied to native tallgrass range in either April, August, or September on forage biomass production, soil cover, and basal plant cover.

Study Description: Nine fire-management units (14 ± 6 acres) were burned at 1 of 3 prescribed times: early spring (April 1), mid-summer (August 1), or late summer (September 1). Plant species composition and soil cover were assessed annually each July using a modified step-point technique.

The Bottom Line: Burning during the summer for 4 consecutive years resulted in …

Efficacy Of Zest, Resolve, And Harmony Tank Mixes Used Sequentially In Irrigated Acetolactase Synthase (Als)-Resistant Grain Sorghum, R. S. Currie, P. W. Geier

Kansas Agricultural Experiment Station Research Reports

Palmer amaranth control was best when Cinch was applied preemergence (PRE) fol­lowed by Zest plus atrazine postemergence (POST) or when Cinch ATZ was applied early postemergence (EPOST) with Zest and atrazine. Most herbicides provided excellent crabgrass control. Shattercane control was excellent with all herbicides except Cinch ATZ applied PRE. Minor sorghum stunting was observed with some treatments three days after application, but sorghum had completely recovered within one week. Herbicide-treated grain sorghum yielded 48 to 93 bu/a more grain than untreated sorghum. Sorghum yields were best when Cinch or Cinch ATZ was applied PRE followed by Zest and atrazine POST, …

Sericea Lespedeza Control Strategies Differ In Their Impacts On Overall Range Health And Native Plant Species Composition, G. A. Gatson, W. H. Fick, W. W. Hsu, K C. Olson

Kansas Agricultural Experiment Station Research Reports

Objective: The objective of this study was to evaluate the effects of sericea lespedeza (Lespedeza cuneata) control strategies of late summer prescribed burning and fall her­bicide application on soil cover, native plant populations, and biological diversity.

Study Description: We established 16 individual units within an 80-acre native tallgrass pasture. Each unit was assigned to 1 of 4 treatments: control, spray only, burn only, or burn-plus-spray. Burn only and burn-plus-spray units were burned in early September. Spray only and burn-plus-spray units were sprayed with metsulfuron methyl (Escort XP, DuPont, Wilmington, DE) in late September. The change in …

Palmer Amaranth Populations From Kansas With Multiple Resistance To Glyphosate, Chlorsulfuron, Mesotrione, And Atrazine, V. Kumar, P. W. Stahlman, G. Boyer

Kansas Agricultural Experiment Station Research Reports

Multiple herbicide-resistant (MHR) Palmer amaranth poses a serious management concern for growers across the United States. Since 2014, several Palmer amaranth populations with suspected resistance to most commonly used herbicides were collected in random field surveys across Kansas. This study aimed to characterize the resistance levels to glyphosate (EPSPS inhibitor), mesotrione (HPPD inhibitor), chlorsulfuron (ALS inhibitor), and atrazine (PS II inhibitor) in three suspected MHR Palmer amaranth populations (KW2, PR8, and BT12) compared to a known herbicide-susceptible (SUS) population. Dose-response studies revealed that PR8 and BT12 populations had 7- to 14-fold level resistance to glyphosate, and up to 12-fold level …

Variable Response Of Kochia Accessions To Dicamba And Fluroxypyr In Western Kansas, V. Kumar, P. W. Stahlman, R. Currie, R. Engel, G. Boyer

Kansas Agricultural Experiment Station Research Reports

The rapid development of glyphosate resistance in kochia has increased the use of auxinic herbicides (dicamba and fluroxypyr) in the US Great Plains, including Kansas. Increasing reliance on auxinic herbicides for controlling glyphosate-resistant (GR) kochia may also enhance the evolution of resistance to these herbicide chemistries. The main objectives of this research were to (1) investigate the variation in kochia response to dicamba and fluroxypyr, and (2) characterize the dicamba resistance levels among progeny of kochia accessions collected from western Kansas. Greenhouse experiments were conducted at the Kansas State University Agricultural Research Center near Hays, KS. Discriminate-dose studies with field-use …