A review of the recruitment biology of winter annual weeds in Canada

2009 ◽  
Vol 89 (3) ◽  
pp. 575-589 ◽  
Author(s):  
S. Z.H. Cici ◽  
R. C. Van Acker
Keyword(s):  
Climate Change ◽  
Weed Management ◽  
Management Practices ◽  
Seed Longevity ◽  
Plant Vigour ◽  
Seed Biology ◽  
Winter Annuals ◽  
Winter Annual ◽  
Winter Annual Weeds ◽  
Annual Weeds

Typically, summer annual weeds have been the primary management target for field crop farmers in Canada, but with changes in cropping systems and with acknowledged global climate change there will be an increasing need to consider the management of species that are present very early in the spring, including winter annual weeds. Knowledge of weed recruitment biology and emergence patterns can be used to guide weed management practices. A review was conducted of the recruitment biology of winter annual weeds in Canada. The key finding was that all of the significant winter annual weeds in Canadian agriculture are facultative, with the majority of species emerging at two peak periods, April-May and September-October. For the weed species included in this review, the information available on recruitment and seed biology was far from comprehensive, and for some species there was very little published information, in particular on specific base temperatures for germination, documented field-based emergence periods and data that could be used to create simple predictive population dynamics models, including fecundity (× environment), seed longevity and overwintering probability. This is particularly true with respect to information in Canadian agricultural contexts. A number of questions result from this review, a key one being whether spring versus fall emergence creates significant differences in fundamental biological characteristics of winter annual weeds including seed dormancy status, microsite requirements, phenology, plant vigour and competitive ability. Given that none of the winter annuals in Canada are constitutive and given ongoing climate change, farmers in Canada should be careful not to encourage summer annuals to become winter annuals. Movement away from fall weed management, including tillage and repeated sowing of winter annual crops will encourage facultative winter annual behaviour. In addition, farmers should be wary of invasion by populations of persistent winter annuals including stinkweed, chickweed and American dragonhead.Key words: Facultative winter annual, dormancy, microsites, emergence pattern, seed rain, seed longevity, weed management

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.

Influence of Winter Annual Weed Management and Crop Rotation on Soybean Cyst Nematode (Heterodera Glycines) and Winter Annual Weeds

Weed Science ◽  
2008 ◽  
Vol 56 (1) ◽  
pp. 103-111 ◽  
Author(s):  
J. Earl Creech ◽  
Andreas Westphal ◽  
Virginia R. Ferris ◽  
Jamal Faghihi ◽  
Tony J. Vyn ◽  
...  
Keyword(s):  
Crop Rotation ◽  
Weed Management ◽  
Soybean Cyst Nematode ◽  
Heterodera Glycines ◽  
Cyst Nematode ◽  
Winter Annual ◽  
Winter Annual Weeds ◽  
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.

Influence of Winter Annual Weed Management and Crop Rotation on Soybean Cyst Nematode (Heterodera glycines) and Winter Annual Weeds: Years Four and Five

Weed Science ◽  
2012 ◽  
Vol 60 (4) ◽  
pp. 634-640 ◽  
Author(s):  
Valerie A. Mock ◽  
J. Earl Creech ◽  
Virginia R. Ferris ◽  
Jamal Faghihi ◽  
Andreas Westphal ◽  
...  
Keyword(s):  
United States ◽  
Population Density ◽  
Weed Management ◽  
Soybean Cyst Nematode ◽  
Cyst Nematode ◽  
Weed Density ◽  
Weed Growth ◽  
Winter Annual ◽  
Winter Annual Weeds ◽  
Annual Weeds

Certain winter annual weeds have been documented as alternative hosts to soybean cyst nematode (SCN), and infestations by such species are common in no-till production fields in the midwestern United States of Indiana, Ohio, and Illinois. The objective of this research was to determine the influence of crop rotation and winter annual weed management on winter weed growth, SCN population density, and crop yield. Two crop rotations (SS and soybean–corn rotation) and six winter annual weed-management systems (autumn-applied herbicide, spring-applied herbicide, autumn + spring applied herbicides, autumn-seeded Italian ryegrass, autumn-seeded wheat, and a nontreated check) were evaluated in long-term, no-tillage systems at West Lafayette, IN, and Vincennes, IN. In the fourth and fifth years of these experiments, the 2-yr corn–soybean rotation generally resulted in increased soybean yield, decreased winter annual weed growth, and reduced SCN population density compared with SS. Autumn or spring herbicide applications or both were a more effective option than cover crops at reducing winter annual weed density. Cover-crop systems generally did not differ from the nontreated check in winter weed density. Between years three and five, winter annual weed SCN hosts in nontreated check plots increased approximately threefold to levels as high as 102 and 245 plants m−2 at West Lafayette, IN, and Vincennes, IN, respectively, which are infestation levels at or above those commonly observed in production fields. However, controlling winter annual weeds did not influence crop yields or SCN population density. The results of these studies suggest that winter weed management, even at the high levels of weed infestation present in these studies, appears to have little value as a tool for SCN management in corn and soybean production systems in the midwestern United States.

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.

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.

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

Weed Science ◽  
2010 ◽  
Vol 58 (4) ◽  
pp. 381-386 ◽  
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.

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.

Forage Radish Cover Crop Suppresses Winter Annual Weeds in Fall and Before Corn Planting

2011 ◽  
Vol 103 (1) ◽  
pp. 137-144 ◽  
Author(s):  
Yvonne E. Lawley ◽  
Ray R. Weil ◽  
John R. Teasdale
Keyword(s):  
Cover Crop ◽  
Winter Annual ◽  
Winter Annual Weeds ◽  
Annual Weeds
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