Response of 110 Kentucky Bluegrass Varieties and Winter Annual Weeds to Methiozolin

Methiozolin is a new isoxazoline herbicide that has scarcely been tested in Kentucky bluegrass turf. A field trial was conducted in Blacksburg, VA, to determine response of 110 Kentucky bluegrass varieties and winter annual weeds to sequential fall applications of methiozolin. At 1.5 and 6 mo after initial treatment (MAIT), Kentucky bluegrass injury I30values (predicted methiozolin rate that causes 30% Kentucky bluegrass injury) ranged between 3.4 to more than 10 times the recommended methiozolin rate for annual bluegrass control. Methiozolin at all rates reduced cover of annual bluegrass, common chickweed, corn speedwell, hairy bittercress, mouseear chickweed, and Persian speedwell but increased cover of parsley-piert. For all varieties, methiozolin at 2 kg ai ha−1increased Kentucky bluegrass cover, turf quality, and turf normalized difference vegetation index (NDVI) relative to the nontreated check at 6 MAIT. Kentucky bluegrass relative cover change (RCC) was attributed primarily to weed control but was inversely correlated with methiozolin rates because of increased weed control and reduced Kentucky bluegrass growth. Despite the decline in RCC with increasing methiozolin rates, most Kentucky bluegrass varieties treated with the highest methiozolin rate (6 kg ha−1) still had greater Kentucky bluegrass cover than the nontreated check at 6 MAIT. Results from this study indicate that two fall applications of methiozolin at rates beyond that previously reported for annual bluegrass control can safely be applied to a broad range of Kentucky bluegrass varieties spanning most of the known genetic classifications.

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Strategies for Control of Horseweed (Conyza canadensis) and Other Winter Annual Weeds in No-Till Corn

Weed Technology ◽

10.1614/wt-08-094.1 ◽

2009 ◽

Vol 23 (3) ◽

pp. 379-383 ◽

Cited By ~ 4

Author(s):

Gregory R. Armel ◽

Robert J. Richardson ◽

Henry P. Wilson ◽

Thomas E. Hines

Keyword(s):

Field Studies ◽

Conyza Canadensis ◽

Weed Species ◽

Annual Bluegrass ◽

No Till ◽

Winter Annual ◽

Winter Annual Weeds ◽

Annual Weeds

Field studies were conducted to determine if mesotrione alone or in combinations with other corn herbicides would control horseweed and other winter annual weeds associated with no-till corn. Mesotrione alone controlled horseweed 52 to 80% by 3 wk after treatment (WAT); however, by 7 WAT control diminished to between 37 to 68%, depending on mesotrione rate. Mesotrione at 0.16 kg ai/ha plus atrazine at 0.28 kg ai/ha controlled 99% of horseweed and annual bluegrass and 88% of yellow woodsorrel. Combinations of mesotrione at 0.16 kg/ha plus acetochlor at 1.79 kg ai/ha plus 1.12 kg ai/ha glyphosate (trimethylsulfonium salt of glyphosate) or 0.7 kg ai/ha paraquat provided 93% or greater control of all three weed species. Glyphosate alone also controlled all weed species 97 to 99%, while paraquat alone provided 99% control of annual bluegrass, 72% control of horseweed, and 36% control of yellow woodsorrel. Mixtures of paraquat plus acetochlor improved control of horseweed (93%) and yellow woodsorrel (73%) over control with either herbicide applied alone.

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Indaziflam Programs for Weed Control in Overseeded Bermudagrass Turf

HortTechnology ◽

10.21273/horttech.22.6.774 ◽

2012 ◽

Vol 22 (6) ◽

pp. 774-777 ◽

Cited By ~ 5

Author(s):

Gerald M. Henry ◽

James T. Brosnan ◽

Greg K. Breeden ◽

Tyler Cooper ◽

Leslie L. Beck ◽

...

Keyword(s):

Weed Control ◽

Lolium Perenne ◽

Perennial Ryegrass ◽

Untreated Control ◽

Cellulose Biosynthesis ◽

Weed Species ◽

Annual Bluegrass ◽

Winter Annual ◽

Annual Weeds ◽

And Control

Indaziflam is an alkylazine herbicide that controls winter and summer annual weeds in bermudagrass (Cynodon sp.) turf by inhibiting cellulose biosynthesis. Research was conducted in Tennessee and Texas during 2010 and 2011 to evaluate the effects of indaziflam applications on overseeded perennial ryegrass (Lolium perenne) establishment and summer annual weed control. In Texas, perennial ryegrass cover on plots treated with indaziflam at 0.75 and 1.0 oz/acre measured 37% to 48% compared with 88% for the untreated control 257 days after initial treatment (DAIT). Perennial ryegrass cover following applications of indaziflam at 0.5 oz/acre measured 84% 257 DAIT and did not differ from the untreated control on any evaluation date. Inconsistent responses in crabgrass (Digitaria sp.) control with indaziflam at 0.5 oz/acre were observed in Tennessee and Texas. However, control was similar to the 0.75-oz/acre rate and prodiamine at 7.8 oz/acre at each location. A September application of indaziflam at 0.75 oz/acre followed by a sequential treatment at 0.5 oz/acre in March of the following year provided >90% control by June 2011. Indaziflam application regimes of this nature would allow for successful fall overseeding of perennial ryegrass every two years and control winter annual weed species such as annual bluegrass (Poa annua).

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Preplant and Residual Herbicide Application Timings for Weed Control in No-Till Soybean

Weed Technology ◽

10.1017/wet.2018.105 ◽

2019 ◽

Vol 33 (1) ◽

pp. 166-172 ◽

Cited By ~ 1

Author(s):

Kurt M. Vollmer ◽

Mark J. VanGessel ◽

Quintin R. Johnson ◽

Barbara A. Scott

Keyword(s):

Weed Control ◽

Early Spring ◽

Herbicide Application ◽

Emergence Period ◽

No Till ◽

Winter Annual ◽

Winter Annual Weeds ◽

Annual Weeds ◽

Residual Herbicide ◽

Application Programs

AbstractTimely herbicide applications for no-till soybean can be challenging given the diverse communities of both winter and summer annual weeds that are often present. Research was conducted to compare various approaches for nonselective and preplant weed control for no-till soybean. Nonselective herbicide application timings of fall (with and without a residual herbicide) followed by early-spring (4 wk before planting), late-spring (1 to 2 wk before planting), or sequential-spring applications (4 wk before planting and at planting) were compared. Spring applications also included a residual herbicide. For consistent control of winter annual weeds, two herbicide applications were needed, either a fall application followed by a spring application or sequential-spring applications. When a fall herbicide application did not include a residual herbicide, greater winter annual weed control resulted from early- or sequential-spring treatments. However, application timings that effectively controlled winter annual weeds did not effectively control summer annual weeds that have a prolonged emergence period. Palmer amaranth and large crabgrass control at 4 wk after planting was better when the spring residual treatment (chlorimuron plus metribuzin) was applied 1 to 2 wk before planting or at planting, compared with 4 wk before planting. Results indicate that in order to optimize control, herbicide application programs in soybean should coincide with seasonal growth cycles of winter and summer annual weeds.

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Dates of Glyphosate Treatments on Weeds and Bermudagrass(Cynodon dactylon)

Weed Science ◽

10.1017/s0043174500064456 ◽

1978 ◽

Vol 26 (6) ◽

pp. 523-526 ◽

Cited By ~ 6

Author(s):

B. J. Johnson ◽

G. O. Ware

Keyword(s):

Cynodon Dactylon ◽

Poa Annua ◽

Annual Bluegrass ◽

Winter Annuals ◽

Winter Annual ◽

Winter Annual Weeds ◽

Annual Weeds

Glyphosate [N-(phosphonomethyl)glycine] consistently controls many winter annual weeds in dormant bermudagrass [Cynodon dactylon(L.) Pers.] but injures actively growing turf. Experiments were conducted to determine the effects of dates of glyphosate treatments on control of winter annuals in different stages of maturity and on the tolerance of bermudagrass when applied to the turf at different stages of greenness from dormant turf in the winter to actively growing turf in the spring. Glyphosate was applied at rates of 0, 0.3, 0.6, 1.1, and 2.2 kg/ha to different plots of winter annuals and bermudagrass at 3-week intervals from February 13 to May 3. Glyphosate at 0.3 kg/ha controlled at least 90% of annual bluegrass(Poa annuaL.), spur weed(Soliva sessilisP. & K.), and corn speedwell(Veronica arvensisL.) within a 6-week period regardless of the date of treatment. All glyphosate treatments injured bermudagrass when applied to semi-dormant or actively growing turf. Bermudagrass treated with glyphosate at 0.3 kg/ha was injured the least and the turf had essentially recovered by 6 weeks after treatment. However, the injury from higher rates (0.6 to 2.2 kg/ha) was too severe to be acceptable in turf areas. Glyphosate did not severely injure bermudagrass when applied to dormant turf.

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Fall and Spring Preplant Herbicide Applications Influence Spring Emergence of Glyphosate-Resistant Horseweed (Conyza canadensis)

Weed Technology ◽

10.1614/wt-09-064.1 ◽

2010 ◽

Vol 24 (1) ◽

pp. 11-19 ◽

Cited By ~ 23

Author(s):

Vince M. Davis ◽

Greg R. Kruger ◽

Bryan G. Young ◽

William G. Johnson

Keyword(s):

Early Spring ◽

Late Spring ◽

Conyza Canadensis ◽

No Till ◽

Early Fall ◽

Winter Annual ◽

Winter Annual Weeds ◽

Annual Weeds ◽

Spring Emergence ◽

Residual Control

Horseweed (Conyza canadensis) is a common weed in no-till crop production systems. It is problematic because of the frequent occurrence of biotypes resistant to glyphosate and acetolactate synthase (ALS)-inhibiting herbicides and its ability to complete its life cycle as a winter or summer annual weed. Tactics to control horseweed while controlling other winter annual weeds routinely fail; herbicide application timing and spring emergence patterns of horseweed may be responsible. The objectives of this experiment were to (1) determine the influence of fall and spring herbicides with and without soil residual horseweed activity on spring-emerging glyphosate-resistant (GR) horseweed density and (2) evaluate the efficacy and persistence of saflufenacil on GR horseweed. Field studies were conducted in southern Indiana and Illinois from fall 2006 to summer 2007 and repeated in 2007 to 2008. Six preplant herbicide treatments were applied at four application timings: early fall, late fall, early spring, and late spring. Horseweed plants were counted every 2 wk following the first spring application until the first week of July. Horseweed almost exclusively emerged in the spring at both locations. Spring horseweed emergence was higher when 2,4-D + glyphosate was fall-applied and controlled other winter annual weeds. With fall-applied 2,4-D + glyphosate, over 90% of the peak horseweed density was observed before April 25. In contrast, only 25% of the peak horseweed density was observed in the untreated check by April 25. Starting from the initiation of horseweed emergence in late March, chlorimuron + tribenuron applied early fall or early spring, and spring-applied saflufenacil at 100 g ai/ha provided greater than 90% horseweed control for 12 wk. Early spring–applied saflufenacil at 50 g ai/ha provided 8 wk of greater than 90% residual control, and early spring–applied simazine provided 6 wk of greater than 90% control. When applied in late spring, saflufenacil was the only herbicide treatment that reduced horseweed densities by greater than 90% compared to 2,4-D + glyphosate. We concluded from this research that fall applications of nonresidual herbicides can increase the rate and density of spring emerging horseweed. In addition, spring-applied saflufenacil provides no-till producers with a new preplant herbicide for foliar and residual control of glyphosate- and ALS-resistant horseweed.

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Weeds and Alfalfa Hay Quality

Weed Science ◽

10.1017/s0043174500027326 ◽

1973 ◽

Vol 21 (5) ◽

pp. 400-401 ◽

Cited By ~ 20

Author(s):

H. P. Cords

Keyword(s):

Medicago Sativa ◽

Protein Content ◽

Direct Effect ◽

Dormant Period ◽

Alfalfa Hay ◽

Winter Annual ◽

Winter Annual Weeds ◽

Annual Weeds

Established stands of alfalfa (Medicago sativa L. ‘Lahontan’) at six field locations were treated with soil-active herbicides during the dormant period for the control of winter annual weeds. Weeds and alfalfa were hand separated at the first harvest. This forage, which varied widely in weed content, was analyzed for protein. The percentage of protein correlated negatively with weed content in all cases. Analyses of covariance revealed that the direct effect of the herbicides on protein content was either small or absent and that the primary cause of the negative correlations was weed content.

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Influence of Winter Annual Weed Removal Timings on Soybean Cyst Nematode Population Density and Plant Biomass

Weed Science ◽

10.1614/ws-09-072.1 ◽

2010 ◽

Vol 58 (4) ◽

pp. 381-386 ◽

Cited By ~ 2

Author(s):

Valerie A. Mock ◽

J. Earl Creech ◽

Virginia R. Ferris ◽

Steven G. Hallett ◽

William G. Johnson

Keyword(s):

Soybean Cyst Nematode ◽

Plant Biomass ◽

Cyst Nematode ◽

Population Increase ◽

Population Densities ◽

Soybean Production ◽

Winter Annual ◽

Winter Annual Weeds ◽

Annual Weeds ◽

Weed Removal

Soybean cyst nematode (SCN) is one of the most yield limiting pathogens in U.S. soybean production. Henbit and purple deadnettle are winter annual weeds shown to facilitate SCN reproduction after crop harvest in the eastern Corn Belt. These weeds, along with volunteer soybean that germinates in autumn after harvest, are common to postharvest soybean production fields and provide an opportunity for SCN reproduction and population increase outside of the typical soybean production season. The objective of this experiment was to determine if autumn removal of these weeds and volunteer soybean can influence the winter weed seedbank, plant biomass, and SCN population densities. Microplots were established with or without Lamium spp. and volunteer soybean, and four winter weed removal timings (none, October, December, and May). Dry weights of autumn Lamium spp. were reduced 50% in October when grown in competition with volunteer soybean. SCN juveniles were found in henbit roots at higher densities in October (42 per gram of root) than December (5 per gram of root) and were also found in the roots of volunteer soybean (14 per gram of root) in October. SCN egg population densities were 50% lower in August after the summer fallow period. The results of this experiment suggest that autumn removal of winter annual weeds and volunteer soybean did not reduce SCN populations.

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Control of Annual Bluegrass (Poa annua) in Kentucky Bluegrass (Poa pratensis) Turf with Linuron

Weed Technology ◽

10.1017/s0890037x0003637x ◽

1992 ◽

Vol 6 (4) ◽

pp. 852-857 ◽

Cited By ~ 10

Author(s):

J. Christopher Hall ◽

C. Ken Carey

Keyword(s):

Field Experiments ◽

Poa Pratensis ◽

Stand Density ◽

Normal Growth ◽

Dry Weight ◽

Kentucky Bluegrass ◽

Controlled Environment ◽

Annual Bluegrass ◽

Turf Quality ◽

Severe Reduction

Effects of linuron on annual bluegrass control and Kentucky bluegrass cultivar tolerance were studied in field and growth chamber experiments. In controlled environment experiments, linuron at 0.06, 0.12, 0.25, 0.50, and 0.75 kg ai ha-1 was applied to pure stands of annual bluegrass and eight Kentucky bluegrass cultivars. Linuron at the two highest rates controlled annual bluegrass, reducing the clipping dry weight by more than 85% 4 wk after treatment, and by 65 to 92% 6 wk after treatment. Growth of Kentucky bluegrass was reduced with the most severe reduction occurring 2 wk after linuron application. All cultivars exhibited normal growth 8 wk after treatment. In field experiments, linuron at rates from 1.5 to 2.0 kg ai ha-1 controlled annual bluegrass in old (> 5 yr) Kentucky bluegrass stands, and in 16 cultivars of 1-yr and 2-yr-old Kentucky bluegrass stands, with little or no damage. At rates of 1.5, 2.0, and 2.5 kg ai ha-1 linuron, damage to newly seeded cultivars was moderate to severe. However, 6 to 7 wk after linuron application to newly seeded cultivars, stand density and turf quality were equivalent to untreated checks.

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