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

2009 ◽  
Vol 23 (3) ◽  
pp. 379-383 ◽  
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.

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

2010 ◽  
Vol 24 (1) ◽  
pp. 11-19 ◽  
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.

Weed Control with Fall and Early-Preplant Herbicide Applications in No-Till Soybean

2004 ◽  
Vol 18 (4) ◽  
pp. 887-892 ◽  
Author(s):  
Ryan F. Hasty ◽  
Christy L. Sprague ◽  
Aaron G. Hager
Keyword(s):  
Weed Control ◽  
Field Studies ◽  
Application Rate ◽  
Weed Species ◽  
Annual Bluegrass ◽  
No Till ◽  
Winter Annual

Field studies were conducted during 1999 and 2000 to compare weed control after fall and early-preplant (EPP) herbicide applications in no-till soybean. Three residual treatments (chlorimuron plus metribuzin, chlorimuron plus sulfentrazone, and metribuzin) were applied at two rates and timings (fall and 30 d EPP) either alone or in combination with glyphosate and 2,4-D. The addition of glyphosate and 2,4-D to fall-applied residual herbicides significantly increased control of common chickweed, annual bluegrass, cressleaf groundsel, and shepherd's-purse. The effect of application rate on weed control was species dependent. Fall-applied residual herbicides were comparable with EPP treatments with respect to winter annual weed control; however, at planting control of summer annual weed species with fall treatments was less consistent compared with EPP residual herbicides.

Winter Annual Weed Suppression in Rye–Vetch Cover Crop Mixtures

2012 ◽  
Vol 26 (4) ◽  
pp. 818-825 ◽  
Author(s):  
Zachary D. Hayden ◽  
Daniel C. Brainard ◽  
Ben Henshaw ◽  
Mathieu Ngouajio
Keyword(s):  
Cover Crops ◽  
Cover Crop ◽  
Field Experiments ◽  
Dry Weight ◽  
Weed Suppression ◽  
Weed Species ◽  
Cereal Rye ◽  
Winter Annual ◽  
Winter Annual Weeds ◽  
Annual Weeds

Winter annual weeds can interfere directly with crops and serve as alternative hosts for important pests, particularly in reduced tillage systems. Field experiments were conducted on loamy sand soils at two sites in Holt, MI, between 2008 and 2011 to evaluate the relative effects of cereal rye, hairy vetch, and rye–vetch mixture cover crops on the biomass and density of winter annual weed communities. All cover crop treatments significantly reduced total weed biomass compared with a no-cover-crop control, with suppression ranging from 71 to 91% for vetch to 95 to 98% for rye. In all trials, the density of nonmustard family broadleaf weeds was either not suppressed or suppressed equally by all cover crop treatments. In contrast, the density of mustard family weed species was suppressed more by rye and rye–vetch mixtures than by vetch. Cover crops were more consistently suppressive of weed dry weight per plant than of weed density, with rye-containing cover crops generally more suppressive than vetch. Overall, rye was most effective at suppressing winter annual weeds; however, rye–vetch mixtures can match the level of control achieved by rye, in addition to providing a potential source of fixed nitrogen for subsequent cash crops.

Buckwheat Residue Effects on Emergence and Growth of Weeds in Winter-Wheat (Triticum aestivum) Cropping Systems

Weed Science ◽  
2011 ◽  
Vol 59 (4) ◽  
pp. 567-573 ◽  
Author(s):  
Virender Kumar ◽  
Daniel C. Brainard ◽  
Robin R. Bellinder ◽  
Russell R. Hahn
Keyword(s):  
New York ◽  
Winter Wheat ◽  
Weed Management ◽  
Cropping Systems ◽  
Soil Surface ◽  
Bare Soil ◽  
Weed Species ◽  
Winter Annual ◽  
Winter Annual Weeds ◽  
Annual Weeds

Field and pot studies were conducted in Central New York to determine the potential weed-management benefits of a buckwheat cover crop grown before winter wheat. Specific objectives were to determine buckwheat residue effects on (1) emergence and growth of winter annual weeds; (2) wheat establishment and yield; and (3) emergence of summer annual weeds in the spring following overwinter seed burial. In a field study, buckwheat was sown at two timings (July or August), mowed, and either incorporated or left on the soil surface. Winter wheat was drilled into buckwheat residue in September and weed and crop growth were monitored. In a complementary pot study, four winter annual weeds were sown in soil removed from buckwheat and bare-soil plots at 0 or 15 d after incorporation and monitored for emergence and early growth. To assess buckwheat residue effects on spring emergence from overwintering seeds, seeds of three weed species were buried in buckwheat residue and bare-soil plots in the fall, exhumed in April, and evaluated for emergence. To investigate the mechanism for possible effects of buckwheat residue on overwintering seeds, two levels each of seed treatment (none or fungicide) and fertilization (none or 170 kg ha−1) were applied before burial. Buckwheat residue had no negative effect on wheat yields but suppressed emergence (22 to 72%) and growth (0 to 95%) of winter annual weeds, although effects were often small and inconsistent. Buckwheat residue had no effect on the emergence of buried weed seeds in spring. However, fungicide treatment enhanced the emergence of Powell amaranth seeds by 12.5 to 25.5% and of barnyardgrass seeds by 0 to 12%. Our results suggest that buckwheat residue can contribute to weed management in wheat cropping systems, but that further studies investigating the mechanistic basis for the inconsistent selective effects of buckwheat residue on weeds are needed before buckwheat use can be optimized.

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

2016 ◽  
Vol 30 (4) ◽  
pp. 965-978 ◽  
Author(s):  
Sandeep S. Rana ◽  
Shawn D. Askew
Keyword(s):  
Weed Control ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Kentucky Bluegrass ◽  
Annual Bluegrass ◽  
Turf Quality ◽  
Relative Cover ◽  
Winter Annual ◽  
Winter Annual Weeds ◽  
Annual Weeds

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.

Short Communication: Timing of stinkweed and shepherd's-purse recruitment affects biological characteristics of progeny

2012 ◽  
Vol 92 (5) ◽  
pp. 933-936 ◽  
Author(s):  
Rene C. Van Acker ◽  
S. Zahra H. Cici
Keyword(s):  
Short Communication ◽  
Biological Characteristics ◽  
Weed Species ◽  
Thlaspi Arvense ◽  
Winter Annual ◽  
Winter Annual Weeds ◽  
Germination Timing ◽  
And Performance ◽  
Annual Weeds ◽  
Seed Characteristics

Van Acker, R. C. and Cici, S. Z. H. 2012. Short Communication: Timing of stinkweed and shepherd's-purserecruitment affects biological characteristics of progeny. Can. J. Plant Sci. 92: 933–936. The effect of recruitment timing (fall versus spring recruitment) on seed characteristics and performance of two common Canadian facultative winter annual weeds; stinkweed (Thlaspi arvense L.) and shepherd's-purse (Capsella bursa-pastoris L.) was investigated. Seed germination proportion was unaffected by maternal emergence timing but germination was faster for spring versus winter cohort seeds of stinkweed. Proportionally more seeds from winter (fall-recruited) cohorts were rendered non-viable by aging treatments, while for shepherd's purse, aging treatments broke dormancy instead of reducing viability and this was especially true for winter cohort seeds. For both weed species, spring cohort seeds produced earlier flowering plants with greater and lesser biomass allocation to reproductive tissues and roots, respectively. These results show the potential importance of germination timing and maternal effects on weed populations and demonstrate additional complexity in the nature of facultative winter annual weeds, in particular.

scholarly journals Indaziflam Programs for Weed Control in Overseeded Bermudagrass Turf

2012 ◽  
Vol 22 (6) ◽  
pp. 774-777 ◽  
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).

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

2019 ◽  
Vol 33 (1) ◽  
pp. 166-172 ◽  
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.

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

Weed Science ◽  
1978 ◽  
Vol 26 (6) ◽  
pp. 523-526 ◽  
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.

Weeds and Alfalfa Hay Quality

Weed Science ◽  
1973 ◽  
Vol 21 (5) ◽  
pp. 400-401 ◽  
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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