Farmer Perceptions of Weed Problems in Corn and Soybean Rotation Systems

2006 ◽  
Vol 20 (3) ◽  
pp. 751-755 ◽  
Author(s):  
K. D. Gibson ◽  
W. G. Johnson ◽  
D. E. Hillger

Corn and soybean growers across Indiana were surveyed in 2003 to determine their perceptions of the importance of weed problems in various crop rotations. Growers were asked to list the three most problematic weeds in the following rotation systems: soybean and corn planted in alternate years (SC) and corn (CC) or soybean (SS) planted to the same field for 2 or more years. Although some summer annuals and perennials (common lambsquarters, Canada thistle, and common cocklebur) and winter annuals (chickweed and henbit) were considered problematic by at least 10% of growers in all three systems, there were differences among systems in the relative importance of weed species. Giant ragweed was considered problematic by at least 30% of SC and CC growers but by less than 10% of SS growers. Horseweed was listed as a problematic summer annual by 13% of SS growers but by only 3% of CC growers. Purple deadnettle was listed by 15% of CC growers but by less than 6% of SC and SS growers. Perennial dicots were more problematic in SS than in CC. Annual and perennial grasses were more problematic in CC than in SC or SS. Despite these differences, the results of this survey suggest that the cumulative effect of weed management practices in corn and soybean rotation systems in Indiana has been the promotion of larger seeded, broadleaf, summer annual species.

2013 ◽  
Vol 27 (4) ◽  
pp. 798-802 ◽  
Author(s):  
RaeLynn A. Butler ◽  
Sylvie M. Brouder ◽  
William G. Johnson ◽  
Kevin D. Gibson

Greenhouse experiments were conducted in 2011 to evaluate the effect of mowing frequency and mowing height on four summer annual weed species (large crabgrass, barnyardgrass, giant ragweed, and common lambsquarters). Plants were clipped at three heights (5, 10, or 20 cm) and at two frequencies (single clipping or repeated clippings at the same height) to simulate mowing. A nonclipped control was also grown for each species. When clipped once, large crabgrass, barnyardgrass, and giant ragweed produced at least 90% of the total dry weight (DW) of the nonclipped plants, and common lambsquarters produced at least 75%. A single cut was generally not sufficient to prevent weed seed production or kill any of the weeds in this study. Repeated clipping reduced large crabgrass, giant ragweed, and common lambsquarters reproductive DW to 46, 27, and 10% respectively, of the nonclipped control. Barnyardgrass plants that were repeatedly clipped produced between 0 and 8% of the seed DW of nonclipped plants, depending on clipping height. Repeated clipping reduced weed total DW to below 40% for all species compared to nonclipped plants. Our results suggest that, unless combined with other weed management practices, repeated mowing may be necessary to limit the growth and seed production of these weed species.


Weed Science ◽  
1999 ◽  
Vol 47 (1) ◽  
pp. 112-122 ◽  
Author(s):  
Anne Légère ◽  
Nathalie Samson

Generalizations concerning the effects of management practices on weed community dynamics often lack robustness, most likely because of the concomitant effects of agronomic and environmental factors. However, such generalizations, when valid, provide useful grounds for predictions and are thus desirable. This study attempted to evaluate the relative importance of crop rotation, tillage, and weed management as factors affecting weed communities and tested the hypothesis of an association between management practices and weeds from certain life cycle groups. Principal component analysis (PCA) of weed density data from a 4-yr field study conducted on a Kamouraska clay and a Saint-André gravelly sandy loam at La Pocatière QC, Canada, identified groups of weed species, while an analysis of variance (ANOVA) of PCA scores associated these groups with management factors. A multivariate analysis of variance (MANOVA) of regression coefficients describing time courses of density for each species confirmed treatment effects. Species segregated roughly according to life cycles. Interactions among weed management intensity, tillage, and crop rotation mostly explained species dominance in the various cropping systems. A first group of species, mostly annual dicots, largely dominated in minimum weed management treatments; their relative importance in each rotation varied with their level of susceptibility to postemergence herbicides. A second group included annuals and perennials, whose commonality seemed to be their tolerance to herbicides; these species also had a particular affinity for chisel and no-till treatments. A third group was formed by perennial species, each with a different response to tillage. The tenuous correspondence between commonly used classification schemes and management factors suggests that other aspects of weed biology (e.g., seed size, dispersal, production, germination requirements, and seedbank longevity) should be considered when trying to explain and predict the presence and dominance of certain weed species with regard to management practices.


Weed Science ◽  
2008 ◽  
Vol 56 (3) ◽  
pp. 400-407 ◽  
Author(s):  
Mohsen B. Mesgaran ◽  
Hamid R. Mashhadi ◽  
Mahmood Khosravi ◽  
Eskandar Zand ◽  
Hasan Mohammad-Alizadeh

Intercropping is an eco-friendly approach for reducing weed problems through nonchemical methods. Intercrop effects on weed community structure have rarely been studied. A 6-yr study was initiated in 1999 and the response of aboveground weed flora (1999–2002 and 2005) and seed bank (2005) to the intercropping of saffron and black zira, two perennial crops was investigated. Mixtures consisted of 0/100, 25/75, 50/50, 75/25, and 100/0 saffron/black zira ratios, each planted at three densities: 30, 50, and 70 plant m−2. The effect of planting density on weed populations was variable and in most cases not significant. However, mixture ratios caused drastic species compositional changes in the weed community for which univariate and multivariate analyses explored four major associations: (1) weeds that favored a higher ratio of saffron in mixtures (e.g., grasses, field bindweed, pigweeds), (2) weeds that preferred a higher ratio of black zira in mixtures (e.g., Persian speedwell, Brassicaceae complex, Polygoaceae complex, and earthsmoke), (3) weeds that were more abundant in 50/50 mixtures (e.g., Caryophyllaceae complex), and (4) weeds that showed no specific pattern (e.g., common lambsquarterss). Pigweeds, prostrate knotweed, and common lambsquarters dominated the viable seed bank with relative densities of 48, 28, and 8%, respectively. The seed bank of most weed species responded to mixture ratios in a similar manner to those of their corresponding aboveground flora. Seed density decreased as soil depth increased, leading to the accumulation of 66, 22, and 12% of viable seeds in soil layers of 0–5, 5–15 and 15–25 cm, respectively. Greater weed and seed densities were found in more pure stands of black zira. These findings contribute to improving current understanding of crop–weed community structures and may help in developing weed management practices.


Weed Science ◽  
2014 ◽  
Vol 62 (4) ◽  
pp. 555-562 ◽  
Author(s):  
Meredith J. Ward ◽  
Matthew R. Ryan ◽  
William S. Curran ◽  
Jeffrey Law

The utility of biological control for weed management in agroecosystems will increase with a greater understanding of the relationships between common weed and granivore species. Giant foxtail is an introduced, summer annual grass weed that is common throughout the United States and problematic in numerous crops.Harpalus pensylvanicus(DeGeer) (Coleoptera: Carabidae) is a common, native, omnivorous carabid beetle with a range that overlaps giant foxtail. In 2004 and 2005,H. pensylvanicuswas captured from farm fields in Centre County, PA, and subjected to laboratory feeding trials to test the preference of giant foxtail and other species on predation byH. pensylvanicus. Weed species seed preference experiments that included “Choice” and “No Choice” treatments were conducted using giant foxtail, common lambsquarters, and velvetleaf. When given a choice amongst the three weed species,H. pensylvanicuspreferred giant foxtail and common lambsquarters seeds equally compared to velvetleaf seeds. When given the choice,H. pensylvanicuspreferred newly dispersed giant foxtail seeds over field-aged seeds. Phenology of giant foxtail seed shed relative toH. pensylvanicusactivity density was also quantified in field experiments in 2005 and 2006. Giant foxtail seed rain was determined by collecting shed seeds from August through October using pan traps. Activity density ofH. pensylvanicuswas monitored for 72-h periods using pitfall traps from June to October. Peak activity density ofH. pensylvanicusoccurred at the onset of giant foxtail seed shed in both years; however, giant foxtail seed shed peaked approximately 30 to 50 d afterH. pensylvanicusactivity density. Future research should focus on management practices that enhance and supportH. pensylvanicuspopulations later in the growing season to maximize suppression of giant foxtail and other weeds that shed palatable seeds later in the season.


1998 ◽  
Vol 12 (3) ◽  
pp. 522-526 ◽  
Author(s):  
Theodore M. Webster ◽  
John Cardina ◽  
Mark M. Loux

The objectives of this study were to determine how the timing of weed management treatments in winter wheat stubble affects weed control the following season and to determine if spring herbicide rates in corn can be reduced with appropriately timed stubble management practices. Field studies were conducted at two sites in Ohio between 1993 and 1995. Wheat stubble treatments consisted of glyphosate (0.84 kg ae/ha) plus 2,4-D (0.48 kg ae/ha) applied in July, August, or September, or at all three timings, and a nontreated control. In the following season, spring herbicide treatments consisted of a full rate of atrazine (1.7 kg ai/ha) plus alachlor (2.8 kg ai/ha) preemergence, a half rate of these herbicides, or no spring herbicide treatment. Across all locations, a postharvest treatment of glyphosate plus 2,4-D followed by alachlor plus atrazine at half or full rates in the spring controlled all broadleaf weeds, except giant ragweed, at least 88%. Giant foxtail control at three locations was at least 83% when a postharvest glyphosate plus 2,4-D treatment was followed by spring applications of alachlor plus atrazine at half or full rates. Weed control in treatments without alachlor plus atrazine was variable, although broadleaf control from July and August glyphosate plus 2,4-D applications was greater than from September applications. Where alachlor and atrazine were not applied, August was generally the best timing of herbicide applications to wheat stubble for reducing weed populations the following season.


2020 ◽  
pp. 7-30
Author(s):  
Md. Golam Mostafa ◽  
Syed Arvin Hassan ◽  
Md. Ehsanul Haq ◽  
Md. Ahasan Habib ◽  
Kaniz Fatema ◽  
...  

A field experiment was conducted in medium fertile soil at Sher-e-Bangla Agricultural University, Dhaka, Bangladesh during November 2017 to April 2018 in Rabi season with a view to evaluate the performance of wheat varieties under different weed control methods. The experiment was carried out with three varieties i.e. BARI Gom-28, BARI Gom-29 and BARI Gom-30 in the main plot and five weed management methods viz. control (no weeding), two hand weeding at 20 and 40 DAS, Panida 33EC (Pendimethalin) @ 2000 ml ha-1 at 5 DAS pre-emergence, Afinity 50.75WP (Isoproturon) 1500 g ha-1 at 25 DAS as post-emergence herbicide and Panida 33EC (Pendimethalin) @ 2000 ml ha-1 at 5 DAS + Afinity 50.75WP (Isoproturon)1500 g ha-1 at 25 DAS in the sub plot in split plot design. Nine different major weed species were found in the field such as Cynodon dactylon, Cyperus rotundus, Echinochloa colonum, Eleusine indica, Chenopodium album, Alternanthera philoxeroides, Brassica kaber, Leliotropium indicum, Vicia sativa. Results reveled that BARI Gom-30 contributed the highest grain yield 3.01 tha-1. Pre-emergence application of Panida 33EC controlled weeds significantly which showed highest growth followed by yield achieved in wheat. BARI Gom-30 in combination with Panida 33EC produced the highest grain yield 3.52 tha-1 while the lowest grain yield 2.09 t ha-1 was obtained from BARI Gom-28 with no weeding treatment. Results reveled that Panida 33EC (pre-emergence) was found more effective to controlling weeds in wheat. Results of the study finally reveled that Panida 33EC might be considered as a feasible option for combating weed and ensuring higher yield in wheat cultivation.


2020 ◽  
Vol 10 ◽  
pp. 1-14
Author(s):  
Charles N. Nyamwamu ◽  
Rebecca Karanja ◽  
Peter Mwangi

This study sought to determine the relation between soil weed seed bank and weed management practices and diversity in farms in Kisii Central Sub County, Western Kenya. Eight administrative sub-locations were randomly selected. Ten farms were selected at equal distance along transect laid across each sub-location. Weed soil seed bank was assessed from soil samples collected from each of the farms; a sub-sample was taken from a composite sample of ten soil cores of 5cm diameter and 15cm deep and placed in germination trays in a greenhouse. Weed diversity in soil weed seedbank was calculated using the Shannon index (H’). Twelve weed species from 12 genera of nine families were recorded. Diversity of the weed species in soil weed seed bank was (H'=1.48). Weed management practises significantly affected weed species soil weed seedbank reserves. Use of inefficient and ineffective hand-weeding techniques resulted in high weed species diversity and abundance.


2000 ◽  
Vol 80 (4) ◽  
pp. 963-972 ◽  
Author(s):  
R. C. Van Acker ◽  
A. G. Thomas ◽  
J. Y. Leeson ◽  
S. Z. Knezevic ◽  
B. L. Frick

In 1997, a weed survey was conducted during July and August in fields of wheat, barley, oat, canola and flax in Manitoba. Field selection was based on a stratified-random sampling methodology using ecodistricts as strata. Species in the Poaceae family were most commonly observed in the survey, followed by species in the Polygonaceae, Asteraceae and Brassicaceae families. The six most abundant weed species were green foxtail [Setaria viridis (L.) Beauv.], wild oats (Avena fatua L.), wild buckwheat (Polygonum convolvulus L.), Canada thistle (Cirsium arvense L.), redroot pigweed (Amaranthus retroflexus L.) and wild mustard (Sinapis arvensis L.). The survey highlighted significant differences between ecoregions and between crops in residual weed infestations. The weed community in the Boreal Transition ecoregion was dominated by seven species, whereas fields in the Aspen Parkland and Lake Manitoba Plain ecoregions were dominated by two species and the Interlake Plain ecoregion was dominated by only one species. Although significant differences were found between the weed communities in crops, they were not as great as differences between ecoregions. The Manitoba residual weed community in 1997 was very similar to that reported for 1978–1981 and 1986, suggesting that the same species should remain a focus for weed management. Key words: Weed survey, weed relative abundance, weed distributions, Manitoba ecoregions


2020 ◽  
Vol 34 (4) ◽  
pp. 607-612 ◽  
Author(s):  
Jessica Quinn ◽  
Nader Soltani ◽  
Jamshid Ashigh ◽  
David C. Hooker ◽  
Darren E. Robinson ◽  
...  

AbstractHorseweed is a competitive summer or winter annual weed that produces up to 230,000 small seeds per plant that are capable of traveling more than 500 km via wind. Giant ragweed is a tall, highly competitive summer annual weed. Glyphosate-resistant (GR) horseweed and GR giant ragweed pose significant challenges for producers in the United States and Ontario, Canada. It is thought that an integrated weed management (IWM) system involving herbicide rotation is required to control GR biotypes. Halauxifen-methyl is a new selective broadleaf POST herbicide registered for use in cereal crops; there is limited information on its efficacy on horseweed and giant ragweed. The purpose of this research was to determine the efficacy of halauxifen-methyl applied POST, alone and in a tank mix, for the control of GR horseweed and GR giant ragweed in wheat across southwestern Ontario. For each weed species, an efficacy study consisting of six field experiments was conducted over a 2-yr period (2018, 2019). At 8 wk after application (WAA), halauxifen-methyl, fluroxypyr/halauxifen-methyl, fluroxypyr/halauxifen-methyl + MCPA EHE, fluroxypyr + MCPA ester, 2,4-D ester, clopyralid, and pyrasulfotole/bromoxynil + ammonium sulfate controlled GR horseweed >95%. Fluroxypyr and MCPA provided only 86% and 37% control of GR horseweed, respectively. At 8 WAA, fluroxypyr, fluroxypyr/halauxifen-methyl, fluroxypyr/halauxifen-methyl + MCPA EHE, fluroxypyr + MCPA ester, fluroxypyr/halauxifen-methyl + MCPA EHE + pyroxsulam, 2,4-D ester, clopyralid, and thifensulfuron/tribenuron + fluroxypyr + MCPA ester controlled GR giant ragweed 87%, 88%, 90%, 94%, 96%, 96%, 98%, and 93%, respectively. Halauxifen-methyl and pyroxsulam provided only 45% and 28% control of GR giant ragweed, respectively. Halauxifen-methyl applied alone POST in the spring controlled GR horseweed but not GR giant ragweed in winter wheat.


2018 ◽  
Vol 32 (6) ◽  
pp. 698-706 ◽  
Author(s):  
Brendan A. Metzger ◽  
Nader Soltani ◽  
Alan J. Raeder ◽  
David C. Hooker ◽  
Darren E. Robinson ◽  
...  

AbstractTolpyralate is a new 4-hydroxyphenyl-pyruvate dioxygenase (HPPD)-inhibiting herbicide for POST weed management in corn; however, there is limited information regarding its efficacy. Six field studies were conducted in Ontario, Canada, over 3 yr (2015 to 2017) to determine the biologically effective dose of tolpyralate for the control of eight annual weed species. Tolpyralate was applied POST at six doses from 3.75 to 120 g ai ha−1and tank mixed at a 1:33.3 ratio with atrazine at six doses from 125 to 4,000 g ha−1. Regression analysis was performed to determine the effective dose (ED) of tolpyralate, and tolpyralate+atrazine, required to achieve 50%, 80%, or 90% control of eight weed species at 1, 2, 4, and 8 wk after application (WAA). The ED of tolpyralate for 90% control (ED90) of velvetleaf, common lambsquarters, common ragweed, redroot pigweed or Powell amaranth, and green foxtail at 8 WAA was ≤15.5 g ha−1; however, tolpyralate alone did not provide 90% control of wild mustard, barnyardgrass, or ladysthumb at 8 WAA at any dose evaluated in this study. In contrast, the ED90for all species in this study with tolpyralate+atrazine was ≤13.1+436 g ha−1, indicating that tolpyralate+atrazine can be highly efficacious at low field doses.


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