YIELD LOSSES IN WHEAT DUE TO WEED COMMUNITIES DOMINATED BY GREEN FOXTAIL [Setaria viridis (L.) BEAUV.]: A MULTISPECIES APPROACH

1989 ◽  
Vol 69 (2) ◽  
pp. 521-529 ◽  
Author(s):  
L. HUME
Keyword(s):  
Yield Loss ◽  
Triticum Aestivum L ◽  
Crop Loss ◽  
Setaria Viridis ◽  
Yield Losses ◽  
Degree Days ◽  
Relative Time ◽  
Weed Communities ◽  
Green Foxtail ◽  
Multispecies Competition

A model was developed to predict wheat (Triticum aestivum L.) loss due to interference by multi-species weed communities dominated by green foxtail [Setaria viridis (L.) Beauv.], 3–4 wk after seeding. Results indicated that green foxtail-dominated weed communities averaging 427 plants m−2 over 4 yr reduced yield by about 7.8%. When plots were kept free of green foxtail, different species became important components of a second model developed to predict the yield loss. The combined effect of precipitation and growing degree days was an important component of both models. It is postulated that these environmental variables reflected the relative time of emergence of the weeds and the crop. Advantages of models based upon multispecies tests over those determined from one-weed one-crop tests are discussed as they relate to crop loss in multispecies situations.Key words: Setaria viridis, green foxtail, crop loss, multispecies competition, weed communities, modeling

Development of equations for estimating yield losses caused by multi-species weed communities dominated by green foxtail [Setaria viridis (L.) Beauv.]

1993 ◽  
Vol 73 (2) ◽  
pp. 625-635 ◽  
Author(s):  
L. Hume
Keyword(s):  
Multiple Regression ◽  
Spring Wheat ◽  
Dry Weight ◽  
Crop Loss ◽  
Regression Equations ◽  
Setaria Viridis ◽  
Important Species ◽  
Weed Communities ◽  
Green Foxtail ◽  
Crop Density

Multiple regression equations were developed to describe the relationship between percentage hard red spring wheat (Triticum aestivum L.) loss and the density and shoot dry weight of multi-species weed communities dominated by green foxtail [Setaria viridis (L.) Beauv.]. Data were collected over a 10-yr period from fields sown by farmers near Regina, Saskatchewan. Weed densities averaged 470 plants m−2, with green foxtail constituting 85% of the total number of plants and 57% by dry weight. Other important species included in the equations were stinkweed (Thlaspi arvense L.), common lamb’s-quarters (Chenopodium album L.), wild buckwheat (Polygonum convolvulus L.), and wild mustard (Sinapis arvensis L.). Including crop density as a variable made a significant improvement in the efficiency of the equations. Precipitation and growing degree-days (base 5 °C) were related to the residuals from the analysis relating wheat loss to weed abundance. These environmental variables were significantly related to crop loss, but only for the residuals of the equation where weed densities were used as independent variables. Hyperbolic and sigmoidal equations were less efficient at describing the data than were multiple linear regression equations. Key words: Green foxtail, spring wheat, competition, multi-species, multiple regression, crop loss

Volunteer Potato Density Influences Critical Time of Weed Removal in Bulb Onion

2007 ◽  
Vol 21 (1) ◽  
pp. 136-140 ◽  
Author(s):  
Martin M. Williams ◽  
Corey V. Ransom ◽  
W. Mack Thompson
Keyword(s):  
Yield Loss ◽  
Critical Time ◽  
Field Trials ◽  
Growing Degree Days ◽  
Crop Loss ◽  
Yield Losses ◽  
Degree Days ◽  
Potato Plants ◽  
Volunteer Potato ◽  
Weed Removal

Volunteer potato is highly competitive with onion and few control tactics are effective for removing this weed from an onion crop. Both volunteer potato density and duration of interference reduce onion yield, but the interaction of these factors is unknown. Field trials were conducted in 2003 in Idaho, Oregon, and Washington to determine the influence of volunteer potato density on the critical time of weed removal (CTWR) in onion. Yield losses of 2.5, 5.0, and 10% were estimated to occur at 534, 654, and 830 growing degree days (GDD) after onion emergence, respectively, with a volunteer potato density of 0.5 plants/m2. At 2.0 volunteer potato plants/m2, yield losses of 2.5, 5.0, and 10% were estimated to occur at 388, 481, and 598 GDD after onion emergence, respectively. Volunteer potato at 2.0 plants/m2had to be removed at least one onion leaf stage sooner, compared to a weed density of 0.5 plants/m2, to avoid yield loss. Yield loss due to volunteer potato density or duration of interference was greatest among jumbo, colossal, and supercolossal market grades (P ≤ 0.1). Lowering potato tuber density in crops preceding onion will extend the critical time for weed removal and reduce the risk of crop loss.

PROPANIL FOR CONTROL OF GREEN FOXTAIL IN WHEAT AND BARLEY

1980 ◽  
Vol 60 (1) ◽  
pp. 177-184 ◽  
Author(s):  
JAMES H. HUNTER
Keyword(s):  
Triticum Aestivum ◽  
Hordeum Vulgare ◽  
Growth Period ◽  
Triticum Aestivum L ◽  
Setaria Viridis ◽  
Wheat Grain ◽  
Hordeum Vulgare L ◽  
Crop Tolerance ◽  
Green Foxtail ◽  
Excellent Control

In a series of field and greenhouse experiments, propanil (3′, 4′-dichloropropionalide) as a postemergent herbicide provided excellent control of green foxtail (Setaria viridis (L.) Beauv.) in wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.). Although some initial chlorosis occurred, wheat and barley recovered quickly and were considered tolerant to propanil at up to 1 kg/ha applied over a growth period extending from the 2- to 8-leaf stages of the green foxtail. Propanil at rates greater than 1 kg/ha resulted in considerable chlorosis and leaf tip burn, and although grain yields were not reduced, crop tolerance was visually assessed as unsatisfactory. Control of green foxtail was satisfactory with 1 kg/ha at the 2- to 4-leaf stages but not at later stages. Control was significantly better when the spray pressure at application was 310 kPa compared to 207 kPa. Analysis indicated that at the 2 and 4 kg/ha rate of propanil the residues in wheat and barley disappeared very quickly. At harvest, wheat grain contained 0.09 ppm of propanil.

SEASONAL EMERGENCE AND PERSISTENCE OF GREEN FOXTAIL

1973 ◽  
Vol 53 (2) ◽  
pp. 369-376 ◽  
Author(s):  
J. D. BANTING ◽  
E. S. MOLBERG ◽  
J. P. GEBHARDT
Keyword(s):  
Triticum Aestivum ◽  
Triticum Aestivum L ◽  
Setaria Viridis ◽  
Primary Dormancy ◽  
Secondary Dormancy ◽  
Green Foxtail

Green foxtail, Setaria viridis (L.) Beauv., emerged at the same time in the spring as the wheat Triticum aestivum L. This was attributed to faster growth of green foxtail when the soil warmed up and its emergence from shallower depths than the wheat. There was a flush of emergence in the spring. Subsequent emergence appeared to depend on rainfall but some seedlings emerged in every 2-wk period throughout the season and in some years as late as October. A buildup of seeds occurred with the 3-yr rotation, i.e., when wheat was sown as a second crop. Germination was primarily controlled by temperature. No germination occurred in 10 days at 4.4 C and only a limited amount at 10 C. Eleven to 26% of the seeds in the soil and 7% of those on the surface were viable after 4 yr. Persistence increased markedly with depth, which emphasizes the need for shallow tillage. Primary dormancy disappeared rapidly. Secondary dormancy was detected thereafter in as many as 24% of the seeds.

EFFECTS OF COMBINED APPLICATIONS OF TRIALLATE OR TRIFLURALIN WITH SOLUTION NITROGEN ON WHEAT, WILD OATS AND GREEN FOXTAIL

1977 ◽  
Vol 57 (2) ◽  
pp. 479-484 ◽  
Author(s):  
J. R. MOYER ◽  
R. D. DRYDEN
Keyword(s):  
Triticum Aestivum ◽  
Nitrogen Content ◽  
Nitrogen Fertilizer ◽  
Good Control ◽  
Triticum Aestivum L ◽  
Avena Fatua ◽  
Setaria Viridis ◽  
Wheat Grain ◽  
Wild Oats ◽  
Green Foxtail

Tank mixtures of solution nitrogen, triallate [S-(2,3,3-trichloroallyl)diisopropyl-thiocarbamate] and/or trifluralin [α,α,α,-trifluro-2, 6-dinitro-N, N-dipropyl-p-toluidine] were evaluated for the control of wild oats (Avena fatua L.) and/or green foxtail (Setaria viridis (L.) Beauv.). The response of wheat (Triticum aestivum L.) cv. Neepawa to solution nitrogen applied alone or in combination with triallate and/or trifluralin were evaluated. Good control of wild oats and green foxtail was obtained with a tank mixture of solution nitrogen, trifluralin at 1.38 kg/ha, and triallate at 1.65 kg/ha. Tank mixtures of triallate at 1.65 kg/ha with solution nitrogen controlled wild oats. Trifluralin at 1.38 kg/ha with solution nitrogen controlled wild oats and green foxtail. Control of green foxtail and wild oats resulted in increased wheat yields, higher nitrogen content in wheat grain, and a more efficient use of applied nitrogen fertilizer. The response of wheat to nitrogen was similar when nitrogen was applied in tank mixes with herbicides or with water to hand-weeded plots.

Tillage and rotation influences on weed community composition in wheat (Triticum aestivum L.) in southwestern Saskatchewan

1991 ◽  
Vol 71 (3) ◽  
pp. 783-789 ◽  
Author(s):  
L. Hume ◽  
S. Tessier ◽  
F. B. Dyck
Keyword(s):  
Triticum Aestivum ◽  
Community Composition ◽  
Sandy Loam ◽  
Triticum Aestivum L ◽  
Conventional Tillage ◽  
Soil Disturbance ◽  
Setaria Viridis ◽  
Tillage Practices ◽  
Green Foxtail ◽  
Hordeum Jubatum

The effects on weed community composition of zero-, minimum-, and conventional tillage practices were examined on three soil types under both continuous wheat (Triticum aestivum L.) and wheat-fallow rotations between 1982 and 1989. Green foxtail [Setaria viridis (L.) Beauv.] became a problem on continuously cropped plots, especially on the sandy loam soil where densities reached a maximum of 2354 plants m−2 with conventional tillage. Without tillage, high densities of foxtail barley (Hordeum jubatum L.) developed since this species was not adequately controlled by herbicides. Even in a year when precipitation was only 63% of normal, perennial shoots of this species achieved a maximum density of 1222 plants m−2. A hoe seeder tended to improve foxtail barley control relative to the disc seeder used, likely due to greater soil disturbance. Wheat losses were significantly correlated to weed density, and it was concluded that, in terms of weed control in wheat, some degree of tillage may be required in southwestern Saskatchewan. Key words: Tillage, Setaria viridis, green foxtail, Hordeum jubatum, foxtail barley, wheat

scholarly journals Estimating Yield and Economic Loss from Constriction Canker of Peach

Plant Disease ◽  
2000 ◽  
Vol 84 (9) ◽  
pp. 941-946 ◽  
Author(s):  
Norman Lalancette ◽  
Dean F. Polk
Keyword(s):  
Yield Loss ◽  
Disease Incidence ◽  
Economic Loss ◽  
Control Measures ◽  
Economic Losses ◽  
Crop Loss ◽  
Friedman Test ◽  
Yield Losses ◽  
Yield Level ◽  
Total Crop

Constriction cankers, caused by Phomopsis amygdali, girdle and kill fruiting twigs which results in a direct crop loss. To quantitatively determine this loss from 1996 to 1998, the number of fruit lost per infected shoot was estimated as a function of disease incidence in 21 severely infected orchards in New Jersey. For each cultivar in 1997 and 1998, the distribution of fruit sizes at harvest and prices at shipping were used to calculate total crop value for typical expected yields. Economic loss was then calculated from yield loss and crop value estimates. The overall percent yield loss mean across all sites and cultivars, unadjusted for fruit remaining on infected shoots, was 22.2, 30.7, and 23.7% for 1996, 1997, and 1998, respectively. The frequency of these losses were not normally distributed, and the nonparametric Friedman test indicated that yield loss was significantly different among years. Assuming the remaining fruit on infected shoots were harvested, yield losses for 1997 and 1998 were 28.5 and 21.0%, which translated into average economic losses of $4,009 and 2,803/ha, respectively, for an expected yield level of 14,010 kg/ha. These loss values justify control measures for management of constriction canker in severely infected orchards.

scholarly journals Understanding Yield Loss and Pathogen Biology to Improve Disease Management: Septoria Nodorum Blotch - A Case Study in Wheat

Plant Disease ◽  
2018 ◽  
Vol 102 (4) ◽  
pp. 696-707 ◽  
Author(s):  
Andrea Ficke ◽  
Christina Cowger ◽  
Gary Bergstrom ◽  
Guro Brodal
Keyword(s):  
Disease Management ◽  
Plant Pathogens ◽  
Management Practices ◽  
Yield Loss ◽  
Control Measures ◽  
Crop Loss ◽  
Yield Losses ◽  
Disease Epidemiology ◽  
Economic Thresholds ◽  
Host Pathogen

The estimated potential yield losses caused by plant pathogens is up to 16% globally and most research in plant pathology aims to reduce yield loss in our crops directly or indirectly. Yield losses caused by a certain disease depend not only on disease severity, but also on the weather factors, the pathogen’s aggressiveness, and the ability of the crop to compensate for reduced photosynthetic area. The yield loss-disease relationship in a certain host-pathogen system might therefore change from year to year, making predictions for yield loss very difficult at the regional or even at the farmer’s level. However, estimating yield losses is essential to determine disease management thresholds at which acute control measures such as fungicide applications, or strategic measures such as crop rotation or use of resistant cultivars are economically and environmentally sensible. Legislation in many countries enforces implementation of integrated pest management (IPM), based on economic thresholds at which the costs due to a disease justify the costs for its management. Without a better understanding of the relationship between disease epidemiology and yield loss, we remain insufficiently equipped to design adequate IPM strategies that will be widely adapted in agriculture. Crop loss studies are resource demanding and difficult to interpret for one particular disease, as crops are usually not invaded by only one pest or pathogen at a time. Combining our knowledge on disease epidemiology, crop physiology, yield development, damage mechanisms involved, and the effect of management practices can help us to increase our understanding of the disease-crop loss relationship. The main aim of this paper is to review and analyze the literature on a representative host-pathogen relationship in an important staple food crop to identify knowledge gaps and research areas to better assess yield loss and design management strategies based on economic thresholds.

CONTROL OF GREEN FOXTAIL IN CEREALS WITH AC 206,784, ALONE AND IN MIXTURES WITH TRIALLATE FOR WILD OATS

1982 ◽  
Vol 62 (4) ◽  
pp. 995-1001
Author(s):  
P. A. O’SULLIVAN ◽  
P. N. P. CHOW ◽  
J. H. HUNTER ◽  
K. J. KIRKLAND
Keyword(s):  
Root Zone ◽  
Soil Surface ◽  
Triticum Aestivum L ◽  
Western Canada ◽  
Setaria Viridis ◽  
Hordeum Vulgare L ◽  
Leaf Stage ◽  
Wild Oats ◽  
Soil Zone ◽  
Green Foxtail

Control of green foxtail (Setaria viridis (L.) Beauv.) with AC 206,784 (2-chloro-N-isopropyl-2′,3′-acetoxylidide) was evaluated at four locations in western Canada. With soil applications, control was good at Lacombe in 1978 but poor at Lacombe and Regina during 1979. Control was good at Brandon and Scott in 1979. At two locations in 1979, soil surface (PE) applications were less effective for control of green foxtail than preplant-incorporated (PPI) treatments. PPI treatments to a depth of 5 cm were more effective than PPI to 10 cm. Soil applications of AC 206,784 did not control wild oats (Avena fatua L.) or injure wheat (Triticum aestivum L.) under field conditions but did provide suppression of these species under greenhouse conditions. Barley (Hordeum vulgare L.) tolerance to AC 206,784 was good. Treating the soil zone containing the emerging coleoptiles of green foxtail and wheat caused more injury that treating the root zone. Application of AC 206,784 as a tank-mixture with triallate did not affect its activity on green foxtail or influence triallate activity on wild oats. In field and greenhouse experiments, control of green foxtail with AC 206,784 applied at the two-leaf stage was variable; at the four-leaf stage it was poor.

Relationships Among Green Foxtail (Setaria viridis) Seedling Development, Growing Degree Days, and Time of Nicosulfuron Application

1996 ◽  
Vol 10 (1) ◽  
pp. 60-67 ◽  
Author(s):  
Frank Forcella ◽  
Kevin R. Banken
Keyword(s):  
Seedling Growth ◽  
Weed Management ◽  
Corn Yield ◽  
Growing Degree Days ◽  
Yield Losses ◽  
Degree Days ◽  
Predictive Tool ◽  
Application Timing ◽  
Green Foxtail ◽  
The Relationship

Success of postemergence weed management often depends upon application timing and weed seedling size. To develop a predictive tool for estimating green foxtail development and optimizing timing of management operations, seedling growth was monitored in fields for two years, as well as in a single greenhouse experiment, and compared with elapsed thermal time (growing degree days, GDD, base 10 C). The relationship between seedling height (mm) and GDD was similar both years and could be described by the following equation: Height = (-0.27 + 0.033 * GDD)2. A comparable equation described seedling growth in a greenhouse. Leaf number was linearly related to GDD. Green foxtail in corn was controlled with nicosulfuron applied at seven intervals between 100 and 450 GDD after corn planting in 1993 and 1994. In 1993 corn yield losses due to green foxtail interference were least when nicosulfuron was applied 200 to 300 GDD after planting, at which time green foxtail height was 50 to 100 mm. In 1994 corn yield losses were minimized if nicosulfuron was applied any time before 300 GDD.

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