Impact of common ragweed (Ambrosia artemisiifolia) aggregation on economic thresholds in soybean

Weed Science ◽  
2003 ◽  
Vol 51 (6) ◽  
pp. 947-954 ◽  
Author(s):  
Michael J. Cowbrough ◽  
Ralph B. Brown ◽  
François J. Tardif
Keyword(s):  
Moisture Content ◽  
Field Experiments ◽  
Yield Loss ◽  
Ambrosia Artemisiifolia ◽  
Threshold Values ◽  
Economic Threshold ◽  
Common Ragweed ◽  
Economic Thresholds ◽  
Significant Difference ◽  
Loss Models

One approach to site-specific weed control is to map weeds within a field and then divide the field area into smaller grid units. The decision to apply a herbicide to individual grid units, or decision units, is made by using yield loss models to establish an economic threshold level. However, decision units often contain weed populations with aggregated distributions. Many yield loss models have not considered this because experiments dealing with weed–crop competition typically assume uniform weed distributions. Therefore, these models may overestimate yield losses. Field experiments conducted in 1999 and 2000 compared the effects of common ragweed having a uniform distribution vs. an aggregated distribution on soybean seed yield, moisture content, and dockage. Field experiment data were used to calculate and compare economic thresholds for both distributions. Economic thresholds that considered drying costs and dockage also were compared. There was no significant difference inIparameters (yield loss as density approaches zero) between the two ragweed distributions in either year. Seed moisture content and dockage increased with increasing common ragweed densities, but increases were not significant at the break-even yield loss level. Economic threshold values were similar for both distributions with differences between aggregated and uniform of 0.14 and 0.01 plants m−2in 1999 and 2000, respectively. The economic threshold values were reduced by 0.01 to 0.06 plants m−2when drying costs and dockage were considered.

Volunteer Barley Interference in Spring Wheat Grown in a Zero-Tillage System

Weed Science ◽  
2007 ◽  
Vol 55 (1) ◽  
pp. 70-74 ◽  
Author(s):  
John T. O'Donovan ◽  
K. Neil Harker ◽  
George W. Clayton ◽  
Linda M. Hall ◽  
Jason Cathcart ◽  
...  
Keyword(s):  
Spring Wheat ◽  
Field Experiments ◽  
Yield Loss ◽  
Wheat Yield ◽  
High Rate ◽  
Initial Slope ◽  
Threshold Values ◽  
Economic Threshold ◽  
Economic Thresholds ◽  
The Impact

There is no published information on the impact of volunteer barley on wheat yield loss or on the economics of controlling barley with a herbicide. With the registration of imazamox-resistant wheat, it is now possible to control volunteer barley in wheat. Thus, the likelihood of growing wheat in rotation with barley may increase. Field experiments were conducted in 2003 and 2004 at Beaverlodge, Lacombe, and Edmonton, AB, Canada, and Saskatoon, SK, Canada, to determine the impact of volunteer barley on yield of imazamox-resistant spring wheat seeded at relatively low (100 kg ha−1) and high (175 kg ha−1) rates. Barley was seeded at different densities to simulate volunteer barley infestations. Regression analysis indicated that wheat-plant density influenced the effects of volunteer barley interference on wheat yield loss, economic threshold values, and volunteer barley fecundity among locations and years. Economic thresholds varied from as few volunteer barley plants as 3 m−2at Beaverlodge in 2003 and 2004 to 48 m−2at Lacombe in 2003. In most cases, wheat yield loss and volunteer barley fecundity were lower and economic thresholds were higher when wheat was seeded at the higher rate. For example, averaged over both years at Beaverlodge initial slope values (percentage of wheat yield loss at low barley density) were 4.5 and 1.7%, and economic threshold values of volunteer barley plants were 3 m−2and 8 m−2at low and high wheat seeding rates, respectively. Results indicate that volunteer barley can be highly competitive in wheat, but yield losses and wheat seed contamination due to volunteer barley can be alleviated by seeding wheat at a relatively high rate.

Downy Brome (Bromus tectorum) Interference and Economic Thresholds in Winter Wheat (Triticum aestivum)

Weed Science ◽  
1990 ◽  
Vol 38 (3) ◽  
pp. 224-228 ◽  
Author(s):  
Phillip W. Stahlman ◽  
Stephen D. Miller
Keyword(s):  
Winter Wheat ◽  
Bromus Tectorum ◽  
Yield Loss ◽  
Wheat Yield ◽  
Dry Weight ◽  
Quadratic Equation ◽  
Downy Brome ◽  
Economic Threshold ◽  
Weed Density ◽  
Economic Thresholds

Densities up to 100 downy brome m2were established in winter wheat in southeastern Wyoming and west-central Kansas to quantify wheat yield loss from downy brome interference and to approximate economic threshold levels. A quadratic equation best described wheat yield loss as a function of weed density when downy brome emerged within 14 days after wheat emergence. Densities of 24, 40, and 65 downy brome m2reduced wheat yield by 10, 15, and 20%, respectively. Wheat yield was not reduced when downy brome emerged 21 or more days later than wheat. Economic thresholds varied with changes in downy brome density, cost of control, wheat price, and potential wheat yield. In a greenhouse experiment, dry weight of 72-day-old wheat plants grown in association with downy brome was not affected by the distance between the weeds and wheat, whereas downy brome plant dry weight increased with increasing distance between the weeds and wheat.

scholarly journals CANOLA YIELD AND PROFITABILITY AS INFLUENCED BY VOLUNTEER WHEAT INFESTATIONS

1989 ◽  
Vol 69 (4) ◽  
pp. 1235-1244 ◽  
Author(s):  
J. T. O’DONOVAN ◽  
K. J. KIRKLAND ◽  
A. K. SHARMA
Keyword(s):  
Triticum Aestivum ◽  
Multiple Regression ◽  
Seed Yield ◽  
Field Experiments ◽  
Yield Loss ◽  
Brassica Campestris ◽  
Triticum Aestivum L ◽  
Economic Threshold ◽  
Rectangular Hyperbola

The effects of different densities of volunteer wheat (Triticum aestivum L. ’Neepawa’) on the yield of canola (Brassica campestris L. ’Tobin’ and B. napus L. ’Westar’), and the seed yield of the volunteer wheat were determined in field experiments conducted at Vegreville, Alberta and Scott, Saskatchewan. Hyperbolic models provided a good fit to the data in most instances and indicated that volunteer wheat can severely reduce canola yield. A model pooled over locations and years indicated that volunteer wheat populations as low as one plant m−2 reduced canola yield by approximately 1%. Yield loss predictions from the models were used to determine the economics of volunteer wheat control with herbicides. In some cases, revenue losses due to reduced canola yield could be alleviated when the value of the volunteer wheat was considered.Key words: Volunteer wheat, canola, rectangular hyperbola, multiple regression, economic threshold, volunteer cereals

Common Ragweed (Ambrosia artemisiifolia) Interference in Soybeans (Glycine max)

Weed Science ◽  
1981 ◽  
Vol 29 (3) ◽  
pp. 339-342 ◽  
Author(s):  
H. D. Coble ◽  
F. M. Williams ◽  
R. L. Ritter
Keyword(s):  
Glycine Max ◽  
Natural Population ◽  
Photosynthetically Active Radiation ◽  
Yield Loss ◽  
Damage Threshold ◽  
Growing Season ◽  
Ambrosia Artemisiifolia ◽  
Common Ragweed ◽  
Active Radiation ◽  
Naturally Occurring

The influence of common ragweed (Ambrosia artemisiifoliaL.) interference on soybean [Glycine max(L.) Merr. ‘Ransom’] yield was studied in the field utilizing naturally occurring weed populations. The damage-threshold population for a full-season, in-row common ragweed infestation was four weeds/10 m of row, which resulted in an 8% yield loss. Soybeans kept weed-free for 2 weeks or longer after emergence in a dry year produced normal yields, but 4 weeks of weed-free maintenance was required when adequate moisture was available early in the growing season. Soybean yield was not reduced by a natural population of common ragweed if the period of interference was limited to 6 weeks or less after crop emergence. By 8 weeks after emergence, common ragweed height averaged 25 cm taller than soybeans, and the weed canopy intercepted 24% of the photosynthetically active radiation.

ECONOMIC THRESHOLD FOR PLANT BUGS, LYGUS SPP. (HETEROPTERA: MIRIDAE), IN CANOLA

1998 ◽  
Vol 130 (6) ◽  
pp. 825-836 ◽  
Author(s):  
I.L. Wise ◽  
R.J. Lamb
Keyword(s):  
Brassica Napus ◽  
Brassica Rapa ◽  
Chemical Control ◽  
Yield Loss ◽  
Field Studies ◽  
Single Application ◽  
Economic Threshold ◽  
Bud Formation ◽  
Economic Thresholds ◽  
And Control

AbstractPlant bugs in the genus Lygus infest canola (Brassica napus L. and Brassica rapa L.) when the crop is producing buds, flowers, and pods. Field studies in cages and open plots show that plant bugs can reduce yield by 20% or more, but have little effect on seed size. A single application of a foliar insecticide when the crop has finished flowering and is beginning to produce pods will prevent most or all of the yield loss. The yield loss of canola that can be prevented by control is 0.007 t/ha per plant bug per 10 sweeps sampled at the end of flowering or the beginning of pod formation. The yield loss that can be prevented by a later application drops to 0.005 t/ha. When precipitation is greater than 100 mm from the onset of bud formation to the end of flowering, the crop may partially compensate for plant bug damage. The economic threshold for control of plant bugs in canola at the end of flowering or at the beginning of pod formation is 15 plant bugs per 10 sweeps, based on crop prices and control costs from 1989 to 1992. If plant bugs are present but control is not warranted when most flowering is complete, plant bug densities should be assessed again 5–7 days later as pods develop, but at this stage the threshold is 20 plant bugs per 10 sweeps. The use of economic thresholds for chemical control of plant bugs will maximize seed yield and minimize unnecessary or ineffectively timed insecticide applications.

scholarly journals Yield Loss and Economic Threshold Level of Soybean due to Leaf Roller (Apoderus cyaneus Hope) in Nepal

1970 ◽  
Vol 6 ◽  
pp. 73-77
Author(s):  
Bishnu K Gyawali
Keyword(s):  
Population Density ◽  
Field Experiments ◽  
Yield Loss ◽  
Threshold Level ◽  
Growth Stages ◽  
Yield Losses ◽  
Adult Beetle ◽  
Economic Threshold ◽  
Leaf Roller ◽  
Research Journal

Yield loss in soybean due to leaf roller (Apoderus cyaneus Hope) was studied at Khumaltarduring 1985 and 1986 seasons. Field experiments were conducted during vegetative as well asreproductive stages of soybean. Rolled leaves of soybean with eggs, grubs and pupae werecollected from the field and reared in the laboratory for adults. Adults were introduced intonylon cages installed at the central rows of each plot just after germination of soybean. Insectswere maintained at population density of 25, 50 and 100 per m2density, the potential grain yield loss of cultivar, Ransom soybean in its vegetative andreproductive stages were 103 and 48 mg per day respectively from each adult of A. cyaneus.Percentages of yield losses were 36.2, 45.2, and 58.0 during vegetative and 37.5, 48.5 and 66.0during reproductive stages from the insect population of 25, 50 and 100, respectively which, wasnot in accordance with the level of two and four fold increased population density of insect.Yield reduction was higher (260 and 108 mg per day) from each adult beetle at lower populationlevel (25) in both vegetative and reproductive stages of soybean.Key words: Economic threshold level; leaf roller; physiological growth stages; yield lossDOI: 10.3126/narj.v6i0.3367Nepal Agriculture Research Journal Vol.6 2005 pp.73-77

scholarly journals Common Ragweed (Ambrosia artemisiifolia L.) Causes Severe Yield Losses in Soybean and Impairs Bradyrhizobium japonicum Infection

Agronomy ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1616
Author(s):  
Rea Maria Hall ◽  
Bernhard Urban ◽  
Helmut Wagentristl ◽  
Gerhard Karrer ◽  
Anna Winter ◽  
...  
Keyword(s):  
Bradyrhizobium Japonicum ◽  
Yield Loss ◽  
Chemical Compounds ◽  
Ambrosia Artemisiifolia ◽  
Yield Losses ◽  
Management Options ◽  
Soybean Yield ◽  
Common Ragweed ◽  
Arable Fields ◽  
The Mean

Ambrosia artemisiifolia L. (Asteraceae), known as common ragweed, is an annual herbaceous species native to North America that has become one of the most economically important weeds in arable fields throughout Central Europe. Its large ecological amplitude enables the species to become established in several types of environments, and management options to effectively contain its spread are limited due to a lack of efficacy, high cost, or lack of awareness. In the last decade, in particular, soybean fields have been severely affected by common ragweed invasion. However, until now, information on the yield-decreasing effects of the plant has been scarce. Therefore, the aim of this study was to evaluate the competition effects of common ragweed on (1) soybean growth (aboveground/belowground), (2) the yield of two different soybean cultivars, and (3) the nodulation potential. Based on a greenhouse and biennial field trial, we found that in plots with the highest common ragweed biomass, the soybean yield loss accounted for 84% compared to the weed-free control, on average. The number of nodules, in addition to the mean nodule weight, which are tightly correlated with soybean yield, were significantly reduced by the presence of common ragweed. Just one common ragweed plant per square meter reduced the number of nodules by 56%, and consequently led to a decrease in yield of 18%. Although it has been reported that the genus Ambrosia produces and releases several types of secondary metabolites, little is known about the influence of these chemical compounds on soybean growth and nodulation. Thus, there is substantial need for research to understand the mechanisms behind the interaction between common ragweed and soybean, with a view to finding new approaches for improved common ragweed control, thereby protecting soybean and other crops against substantial yield losses.

Broccoli (Brassica oleraceavar.botrytis) Yield Loss from Italian Ryegrass (Lolium perenne) Interference

Weed Science ◽  
1995 ◽  
Vol 43 (1) ◽  
pp. 117-120 ◽  
Author(s):  
Carl E. Bell
Keyword(s):  
Weed Control ◽  
Lolium Perenne ◽  
Field Experiments ◽  
Yield Loss ◽  
Threshold Value ◽  
Competition Model ◽  
Italian Ryegrass ◽  
Economic Threshold

Italian ryegrass interference in broccoli was measured in field experiments and the data fit a rectangular hyperbolic competition model. The model predicted 58% of broccoli yield loss related to Italian ryegrass density when pooled over three y. An economic threshold value of 4.9 Italian ryegrass plants m−1of crop row was determined to be the density required to cause a 3.6% yield loss, equal to postemergence weed control costs. Italian ryegrass densities of 600 to 1000 plants m1of broccoli row caused 100% yield loss.

Influence of Common Ragweed (Ambrosia artemisiifolia) Time of Emergence and Density on White Bean (Phaseolus vulgaris)

Weed Science ◽  
1995 ◽  
Vol 43 (3) ◽  
pp. 375-380 ◽  
Author(s):  
David Chikoye ◽  
Stephan F. Weise ◽  
Clarence J. Swanton
Keyword(s):  
Seed Yield ◽  
Yield Loss ◽  
Maximum Yield ◽  
Ambrosia Artemisiifolia ◽  
Parameter Estimates ◽  
Large White ◽  
Area Index ◽  
Common Ragweed ◽  
Weed Density ◽  
White Bean

Common ragweed is a major problem in white bean production systems in Ontario. The influence of time of emergence and density of common ragweed on white bean growth and seed yield was examined in Ontario at Elora in 1990, and at Woodstock and Staffa in 1991 and 1992. Ragweed emerged with white bean seedlings (VE) and at the second trifoliate stage of white bean (V3). Time of ragweed emergence and weed density affected white bean yield at all locations. When 1.5 ragweed seedlings m−1of row emerged at the VE stage of crop growth 10 to 22% seed yield loss occurred. Yield losses of 4 to 9% occurred when 1.5 ragweed seedlings m−1of row emerged at the V3 crop stage. Yield loss parameter estimates, i.e., the predicted weed-free crop yield (YWF) and the maximum yield loss (A), varied among locations and with time of ragweed emergence, whereas the parameter for yield loss at low weed density (I) was more consistent across all locations and times of weed emergence. Although I values were relatively consistent across locations and times of ragweed emergence, the standard errors associated with each estimate were large. White bean leaf area index, above-ground biomass and pod number m−2were affected most by ragweed interference. White bean density, number of seeds per pod, and seed weight per plant were not affected by ragweed interference. Ragweed emerging at VE and V3 produced a maximum of 6000 and 1000 seeds m−2, respectively. Time of ragweed emergence may be more important than weed density when evaluating weed control options.

scholarly journals Soybean yield loss and economic thresholds due to glyphosate resistant hairy fleabane interference

2018 ◽  
Vol 84 (0) ◽  
Author(s):  
Dirceu Agostinetto ◽  
Diecson Ruy Orsolin da Silva ◽  
Leandro Vargas
Keyword(s):  
Yield Loss ◽  
Development Stage ◽  
Control Measures ◽  
Economic Threshold ◽  
Economic Management ◽  
Soybean Yield ◽  
Weed Density ◽  
Economic Thresholds ◽  
Soybean Price ◽  
Hairy Fleabane

ABSTRACT: The interference of glyphosate resistant hairy fleabane (Conyza bonariensis) has caused yield losses in soybean crop. Knowledge of the economic threshold is an important aspect for the economic management of resistant weeds. Because of it, the interference of the glyphosate resistant hairy fleabane density on the soybean yield loss was evaluated, as well as to estimate the economic threshold. Two experiments were conducted to verify the effect of different weed densities on the yield of two soybean cultivars (BRS Estância and BMX Turbo). Weed density ranged from 0 to 124 plants m-2. The yield of the BRS Estância decreased by 1.4% to the increase of one single plant, while for the BMX Turbo the loss was 25.9%. Soybean yield and economic threshold were lower for the BMX Turbo cultivar compared to the cultivar BRS Estância, which can be attributed to the genotype, competitive ability, weed development stage and/or environment. Increases in crop yield expectation, soybean price and herbicide efficiency reduce the economic threshold, indicating that the adoption of control measures should be taken when the weed density is low. Due to the high cost of hairy fleabane control, it is only feasible at high densities.

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