Herbicidal Effects of Vinegar and a Clove Oil Product on Redroot Pigweed (Amaranthus retroflexus) and Velvetleaf (Abutilon theophrasti)

2009 ◽  
Vol 23 (2) ◽  
pp. 292-299 ◽  
Author(s):  
Glenn J. Evans ◽  
Robin R. Bellinder ◽  
Martin C. Goffinet

Weed management can be difficult and expensive in organic agricultural systems. Because of the potentially high cost of the natural product herbicides vinegar and clove oil, their efficacy with regard to weed species growth stages needs to be determined. A further objective was to identify anatomical and morphological features of redroot pigweed and velvetleaf that influence the effectiveness of vinegar and clove oil. Research was conducted on greenhouse-grown cotyledon, two-leaf, and four-leaf redroot pigweed and velvetleaf. Dose–response treatments for vinegar included 150-, 200-, 250-, and 300-grain vinegar at 318 L/ha and at 636 L/ha. Clove oil treatments included 1.7, 3.4, 5.1, and 6.8% (v/v) dilutions of a clove oil product in water (318 L/ha), and a 1.7% (v/v) dilution in 200-grain vinegar (318 L/ha). An untreated control was included. Separate plantings of velvetleaf and pigweed were treated with vinegar or clove oil and were used to study anatomical and morphological differences between the two species. Redroot pigweed was easier to control with both products than velvetleaf. Whereas 200-grain vinegar applied at 636 L/ha provided 100% control (6 d after treatment [DAT]) and mortality (9 DAT) of two-leaf redroot pigweed, this same treatment on two-leaf velvetleaf provided only 73% control and 18% mortality. The obtuse leaf blade angle in velvetleaf moved product away from the shoot tip, whereas in pigweed, the acute leaf blade angle, deep central leaf vein, and groove on the upper side of the leaf petiole facilitated product movement toward the stem axis and shoot tip. For both species, and at all application timings, 150-grain vinegar at 636 L/ha provided control equal to that of 300-grain vinegar at 318 L/ha. As growth stage advanced, control and biomass reduction decreased and survival increased. Application timing will be critical to maximizing weed control with vinegar and clove oil.

2009 ◽  
Vol 23 (3) ◽  
pp. 431-437 ◽  
Author(s):  
Hussein F. H. Abouziena ◽  
Ahmad A. M. Omar ◽  
Shiv D. Sharma ◽  
Megh Singh

There is an urgent need to accelerate the development and implementation of effective organic-compliant herbicides that are environmentally safe and that help the producer meet increasing consumer demand for organic products. Therefore, greenhouse experiments were conducted to evaluate the effectiveness of acetic acid (5%), acetic acid (30%), citric acid (10%), citric acid (5%) + garlic (0.2%), citric acid (10%) + garlic (0.2%), clove oil (45.6%), and corn gluten meal (CGM) compounds as natural-product herbicides for weed control. The herbicides were applied to the broadleaf weeds stranglervine, wild mustard, black nightshade, sicklepod, velvetleaf, and redroot pigweed and to narrowleaf weeds crowfootgrass, Johnsongrass, annual ryegrass, goosegrass, green foxtail, and yellow nutsedge. The herbicides were applied POST at two weed growth stages, namely, two to four and four to six true-leaf stages. CGM was applied PPI in two soil types. Citric acid (5%) + garlic (0.2%) had the greatest control (98%) of younger broadleaf weeds, followed by acetic acid (30%) > CGM > citric acid (10%) > acetic acid (5%) > citric acid (10%) + garlic (0.2%), and clove oil. Wild mustard was most sensitive to these herbicides, whereas redroot pigweed was the least sensitive. Herbicides did not control narrowleaf weeds except for acetic acid (30%) when applied early POST (EPOST) and CGM. Acetic acid (30%) was phytotoxic to all broadleaf weeds and most narrowleaf weeds when applied EPOST. Delayed application until the four- to six-leaf stage significantly reduced efficacy; acetic acid was less sensitive to growth stage than other herbicides. These results will help to determine effective natural herbicides for controlling weeds in organic farming.


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


Weed Science ◽  
1979 ◽  
Vol 27 (1) ◽  
pp. 7-10 ◽  
Author(s):  
R. B. Taylorson

AbstractGermination of seeds of 10 grass and 33 broadleaved weed species was examined for response to ethylene. Germination was promoted in nine species, inhibited in two, and not affected in the remainder. Of the species promoted, common purslane (Portulaca oleraceaL.), common lambsquarters (Chenopodium albumL.), and several Amaranths, including redroot pigweed (Amaranthus retroflexusL.), were affected most. Transformation of phytochrome to the active form (Pfr) gave interactions that ranged from none to syntergistic with the applied ethylene. In subsequent tests seeds of purslane, redroot pigweed, and giant foxtail (Setaria faberiHerrm.), a species not responsive to ethylene, were examined for germination response to 14 low molecular weight hydrocarbon gases other than ethylene. Some stimulation by the olefins propylene and propadiene was found for purslane and pigweed. Propionaldehyde and butyraldehyde were slightly stimulatory to purslane only.


1995 ◽  
Vol 9 (3) ◽  
pp. 531-534 ◽  
Author(s):  
Mark J. Vangessel ◽  
Lori J. Wiles ◽  
Edward E. Schweizer ◽  
Phil Westra

An integrated approach to weed management in pinto bean is needed since available herbicides seldom adequately control all weed species present in a field. A two-year study was conducted to assess weed control efficacy and pinto bean tolerance to mechanical weeding from a rotary hoe or flex-tine harrow at crook, unifoliolate, and trifoliolate stages of bean development. Weed control was similar for both implements and all timings in 1993. In 1994, mechanical weeding at trifoliolate and both crook and trifoliolate stages controlled more weeds than at other growth stages, regardless of type of implement. Using the flex-tine harrow reduced pinto bean stand, but results based on growth stage were not consistent each year. Damage to pinto bean hypocotyls and stems was observed with the flex-tine harrow used at both crook and trifoliolate stages in 1994. Rotary hoeing did not reduce pinto bean stand or cause injury. Yield and seed weight did not differ among treatments in either year.


Weed Science ◽  
1986 ◽  
Vol 34 (1) ◽  
pp. 101-105 ◽  
Author(s):  
John D. Nalewaja ◽  
Grzegorz Skrzypczak

Experiments in controlled-environment chambers indicated that high temperature, 30 C, increased the phytotoxicity of bromoxynil (3,5-dibromo-4-hydroxybenzonitrile) to wild mustard (Sinapis arvensisL. # SINAR) and redroot pigweed (Amaranthus retroflexusL. # AMARE) compared to low temperature, 10 C, during and after treatment. Bromoxynil phytotoxicity generally was higher at relative humidities of 90 to 95% compared to 40 to 60%, but relative humidity had less influence on bromoxynil phytotoxicity than did temperature. A simulated rain immediately after bromoxynil treatment reduced control of both species, but the reduction was of no practical importance for wild mustard. The data indicate that wild mustard and redroot pigweed control would be reduced by bromoxynil application during a period of low temperatures or to plants in advanced growth stages.


HortScience ◽  
2004 ◽  
Vol 39 (2) ◽  
pp. 287-290 ◽  
Author(s):  
Joseph N. Aguyoh ◽  
John B. Masiunas ◽  
Catherine Eastman

Integrated weed management strategies maintain sub-threshold levels of weeds. The remaining weeds may impact the feeding and habitation patterns of both potato leafhoppers and bean leaf beetles in a snap bean agroecosystem. The objective of our study was to determine the effect of interference between snap beans (Phaseolus vulgaris L.) and either redroot pigweed (Amaranthus retroflexus L.) or large crabgrass (Digitaria sanguinalis L.) on populations of potato leafhopper [Empoasca fabae (Harris)] and bean leaf beetle [Cerotoma trifurcata (Forster)]. Plots were seeded with redroot pigweed or large crabgrass at either the same time as snap bean planting (early) or when snap bean had one trifoliate leaf open (late). The weed density averaged two plants per meter of row. Bean leaf beetle populations, snap bean pod damage, and leaf defoliation were lower in weed-free plots compared to those with either early emerging pigweed or crabgrass. Leafhopper nymphs and adults were 31% to 34% less in plots with crabgrass emerging with snap beans compared to those in weed-free snap bean plots. Thus, the effect of sub-threshold densities of pigweed and crabgrass on insect pests in snap bean varied depending on the species and should be considered when deciding to integrate weed management approaches.


HortScience ◽  
2008 ◽  
Vol 43 (5) ◽  
pp. 1492-1494 ◽  
Author(s):  
Darren E. Robinson ◽  
Kristen McNaughton ◽  
Nader Soltani

Pepper growers currently have limited access to many effective broadleaf herbicides. Field trials were conducted over a 3-year period in Ontario to study the effect of tank mixtures of sulfentrazone (100 or 200 g·ha−1 a.i.) with either s-metolachlor (1200 or 2400 g·ha−1 a.i.) or dimethenamid-p (750 or 1500 g·ha−1 a.i.) on transplanted bell pepper. Under weed-free conditions, there was no visual injury or reduction in plant height, fruit number, fruit size, or marketable yield of transplanted pepper with pretransplant applications of sulfentrazone applied in tank mixtures with s-metolachlor or dimethenamid-p. The tank mixture of sulfentrazone + s-metolachlor gave greater than 85% control of redroot pigweed (Amaranthus retroflexus) and eastern black nightshade (Solanum ptycanthum), but only 70% to 76% control of velvetleaf (Abutilon theophrasti), common ragweed (Ambrosia artemisiifolia), and common lambsquarters (Chenopodium album). The combination of sulfentrazone + dimethenamid-p provided good to excellent control of all weed species except velvetleaf. Based on this study, sulfentrazone and dimethenamid-p have potential for minor use registration in pepper.


2020 ◽  
Vol 100 (1) ◽  
pp. 56-67 ◽  
Author(s):  
Gareth Davis ◽  
Jocelyne Letarte ◽  
Christopher M. Grainger ◽  
Istvan Rajcan ◽  
François J. Tardif

The apparent efficacy of linuron to control pigweeds (Amaranthus spp.) has declined in Ontario, Canada, in past decades, possibly due to resistance. Samples were collected in multiple fields across Ontario with reported linuron failure. These were characterized at the whole-plant and molecular levels. Screening with linuron revealed resistance in six out of nine green pigweed (Amaranthus powellii Wats.) populations and 36 out of 38 populations of redroot pigweed (Amaranthus retroflexus L.). Sequencing of the psbA gene showed resistant plants had mutations conferring resistance to photosystem II (PSII) inhibitors. The most commonly seen mutation was coding for a Val219Ile substitution, while other populations had Ala251Val or Phe274Val. Two populations were documented with a double mutation at Val219Ile and Phe274Val. All substitutions endowed plants with low to moderate resistance to linuron, with various levels of cross resistance to other PSII inhibitors. The double mutants were characterized by higher levels of resistance to linuron and diuron compared with each single substitution. The widespread failure of linuron to control pigweed species in many carrot fields in Ontario is due to the selection of PSII mutants. This is the first report of double mutation in psbA in any weed species and the first report of Ala251Val and Phe273Val in pigweed species. The presence of a double mutation is probably the result of continuous selection of plants already resistant due to a single mutation. Our results illustrate the need for diversified weed management strategies in crops where herbicide options are limited.


Weed Science ◽  
1980 ◽  
Vol 28 (5) ◽  
pp. 568-572 ◽  
Author(s):  
G. A. Buchanan ◽  
J. E. Street ◽  
R. H. Crowley

Influence of time of planting and distance from the cotton row of pitted morningglory (Ipomoea lacunosaL.), prickly sida (Sida spinosaL.), and redroot pigweed (Amaranthus retroflexusL.) on yield of seed cotton (Gossypium hirsutumL. ‘Stoneville 213’) was determined on Decatur clay loam during 1975 through 1978. Weed growth was measured in 1977 and 1978. Seeds of the three weed species were planted 15, 30, or 45 cm from the cotton row at time of planting cotton or 4 weeks later. Weeds planted 4 weeks after planting cotton grew significantly less than did weeds planted at the same time as cotton. When planted with cotton, redroot pigweed produced over twice as much fresh weight as did prickly sida or pitted morningglory. The distance that weeds were planted from the cotton row did not affect weed growth in 1978, but did in 1977. The distance that weeds were planted from the cotton row did not affect their competitiveness in any year as measured by yield of cotton. However, in each year, yields of cotton were reduced to a greater extent by weeds planted with cotton than when planted 4 weeks later. In 3 of 4 yr, there were significant differences in competitiveness of each of the three weed species with cotton.


2018 ◽  
Vol 10 (2) ◽  
pp. 15
Author(s):  
Charles L. Webber III ◽  
Paul M. White Jr ◽  
Douglas J. Spaunhorst ◽  
Darcey G. Wayment ◽  
Derek S. Landrum

Allelopathy, the chemical interaction between plants, may result in the inhibition of plant growth and development, and includes compounds released from a primary crop that adversely impact crop or weed species. The objective of this research was to observe the allelopathic impact of sugarcane (Saccharum sp.) post-harvest crop residue and mill bagasse leachate on seed germination of three other plant species. Oat (Avena sative L.) var. ‘Corral’, tall morningglory (Ipomoea purpurea L. Roth), and redroot pigweed (Amaranthus retroflexus L.) seeds were treated with 5 leachate concentrations (0, 12.5, 25, 50, and 100 g/L) from either sugarcane crop residue or sugarcane bagasse. Each experiment was repeated twice (Experiment 1 & 2) with each plant species, leachate concentrations, and leachate source (sugarcane crop residue and mill bagasse). The impact of leachates from sugarcane variety ‘HoCP 96-540’ crop residue and sugarcane bagasse differed by the species evaluated (oat, morningglory, and redroot pigweed), the leachate source (crop residue vs. bagasse), and leachate concentration (0 to 100 g/L). Oat germination was not affected leachate source or concentration. Germination for both weed species, tall morningglory and redroot pigweed, were adversely affected by leachate source and concentration. In both cases, the sugarcane crop residue leachate had a greater deleterious impact on germination than did the bagasse leachate. The response to the leachates was more consistent and severe for tall morningglory germination than redroot pigweed germination. Averaged across experiments, the 12.5 g/L crop residue concentration decreased the tall morningglory germination to 17% compared to 34% germination for the bagasse leachate, and the 100 g/L residue concentration reduce germination to 6% compared to 19% for bagasse 100 g/L bagasse concentration. The 100 g/L concentration of crop residue reduced redroot pigweed germination by 13% (Experiment 1) and 27% (Experiment 2), while the bagasse leachate reduced germination by 5% (Experiment 1) and 15% (Experiment 2). Future research should investigate the allelopathic compounds present in the sugarcane crop residue and bagasse, determine if the same allelopathic compounds are present and in the same concentration among other sugarcane varieties, and further examine which weed and crop species may be vulnerable to the allelopathic compounds present in sugarcane crop residue and bagasse.


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