scholarly journals TRIFLURALIN FOR WEED CONTROL IN CORIANDER, DILL, AND DANDELION

HortScience ◽  
1996 ◽  
Vol 31 (5) ◽  
pp. 757a-757
Author(s):  
J.R. Smart ◽  
D.J. Makus ◽  
R.J. Coleman
Keyword(s):  
Adverse Effects ◽  
Leaf Area ◽  
Weed Control ◽  
Dry Weight ◽  
Field Studies ◽  
Anethum Graveolens ◽  
Crop Tolerance ◽  
Weight Yield ◽  
High Level ◽  
Annual Weeds

Field studies were conducted to determine the efficiency and crop safety of trifluralin [2,6-dinitro-N, N-dipropyl-4(trifluoromethyl) benzenamine] in coriander (Coriandrum sativum L.), dill (Anethum graveolens L.), and dandelion greens (Taraxacum officinale Weber) when applied preplant-incorporated at 0.56 and 0.84 kg a.i./ha. Visual injury evaluations, crop fresh and dry weight at maturity, and leaf area were used to determine adverse effects of trifluralin on each crop when compared to an untreated control. Dandelion greens had a 47% and 49% reduction in leaf area when treated with trifluralin at 0.56 and 0.84 kg a.i./ha when compared to the untreated weed-free dandelion treatment. Coriander and dill showed no visual crop phytotoxicity and no adverse effects on crop growth, fresh and dry weight yield, or leaf area when treated with trifluralin. Trifluralin, when used in combination with early season mechanical cultivation, can provide selective weed control of many of the most common winter annual weeds in south Texas while exhibiting a high level of crop tolerance for coriander and dill.

scholarly journals Determining the critical period for weed control in high-yielding cotton using common sunflower as a mimic weed

2019 ◽  
Vol 33 (6) ◽  
pp. 800-807 ◽  
Author(s):  
Graham W. Charles ◽  
Brian M. Sindel ◽  
Annette L. Cowie ◽  
Oliver G. G. Knox
Keyword(s):  
Weed Control ◽  
Critical Period ◽  
Yield Loss ◽  
Field Studies ◽  
Growing Degree Days ◽  
Degree Days ◽  
Weed Density ◽  
High Level ◽  
The Cost ◽  
Planting Season

AbstractField studies were conducted over six seasons to determine the critical period for weed control (CPWC) in high-yielding cotton, using common sunflower as a mimic weed. Common sunflower was planted with or after cotton emergence at densities of 1, 2, 5, 10, 20, and 50 plants m−2. Common sunflower was added and removed at approximately 0, 150, 300, 450, 600, 750, and 900 growing degree days (GDD) after planting. Season-long interference resulted in no harvestable cotton at densities of five or more common sunflower plants m−2. High levels of intraspecific and interspecific competition occurred at the highest weed densities, with increases in weed biomass and reductions in crop yield not proportional to the changes in weed density. Using a 5% yield-loss threshold, the CPWC extended from 43 to 615 GDD, and 20 to 1,512 GDD for one and 50 common sunflower plants m−2, respectively. These results highlight the high level of weed control required in high-yielding cotton to ensure crop losses do not exceed the cost of control.

Influence of Shading by Soybeans (Glycine max) on Weed Suppression

Weed Science ◽  
1981 ◽  
Vol 29 (5) ◽  
pp. 610-615 ◽  
Author(s):  
T. R. Murphy ◽  
B. J. Gossett
Keyword(s):  
South Carolina ◽  
Glycine Max ◽  
Weed Control ◽  
Field Studies ◽  
Weed Suppression ◽  
Planting Dates ◽  
Early Season ◽  
Soybean Yield ◽  
Annual Weeds

Field studies were conducted at Florence and Clemson, South Carolina to measure the influence of soybean [Glycine max(L.) Merr.] planting dates on the length of early-season weed control needed to prevent yield reductions, the rate of shade development, and suppression of annual weeds by soybeans. The rate of shade development was similar for both planting dates during the 9- to 11-week period after planting for Florence and Clemson, respectively. The period of weed-free maintenance required to prevent soybean yield reductions was not affected by planting dates. With cultivation between rows, early- and late-planted soybeans required 3 weeks of weed-free maintenance to achieve maximum yields. Lower weed weights resulted from late than early soybean plantings. At Clemson, 3 weeks of weed-free maintenance for early and late plantings reduced weed weights 97 and 91%, respectively. Weed weights at Florence were reduced 85% with 3 weeks of weed-free maintenance for the late plantings, whereas 5 weeks were required to reduce weed weights 88% for early plantings.

The Critical Period of Weed Control in Grain Corn (Zea mays)

Weed Science ◽  
1992 ◽  
Vol 40 (3) ◽  
pp. 441-447 ◽  
Author(s):  
Michael R. Hall ◽  
Clarence J. Swanton ◽  
Glenn W. Anderson
Keyword(s):  
Zea Mays ◽  
Leaf Area ◽  
Weed Control ◽  
Critical Period ◽  
Field Studies ◽  
Southern Ontario ◽  
Leaf Stage ◽  
Individual Leaf ◽  
Logistic Equations ◽  
Weed Interference

Field studies were conducted in southern Ontario to determine the critical period of weed control in grain corn and the influence of weed interference on corn leaf area. The Gompertz and logistic equations were fitted to data representing increasing durations of weed control and weed interference, respectively. The beginning of the critical period varied from the 3- to 14-leaf stages of corn development However, the end of the critical period was less variable and ended on average at the 14-leaf stage. Weed interference reduced corn leaf area by reducing the expanded leaf area of each individual leaf and accelerating senescence of lower leaves. In addition, weed interference up to the 14-leaf stage of corn development impeded leaf expansion and emergence in 1989.

Dog mustard (Erucastrum gallicum) response to crop competition

Weed Science ◽  
1997 ◽  
Vol 45 (3) ◽  
pp. 397-403
Author(s):  
David A. Wall
Keyword(s):  
Interspecific Competition ◽  
Leaf Area ◽  
Seed Production ◽  
Growth And Development ◽  
Dry Weight ◽  
Field Studies ◽  
Limiting Factor ◽  
Shoot Dry Weight ◽  
Summer Fallow ◽  
Crop Competition

Greenhouse studies suggested that dog mustard was less competitive than wheat, but of similar competitiveness to flax. In field studies, dog mustard growth and development were markedly affected by crop competition. Competition from flax and wheat reduced dog mustard leaf area, shoot dry weight, plant height, and seed production compared with the weed grown on summer-fallow. Dog mustard was a prolific seed producer when grown in the absence of interspecific competition. On summer-fallow, dog mustard produced as many as 79,100 seeds plant−1when moisture was not a limiting factor. However, average seed production was 19,400 and 8000 seeds plant−1in 1994 and 1995, respectively.

Weed management with CGA-362622 in transgenic and nontransgenic cotton

Weed Science ◽  
2003 ◽  
Vol 51 (6) ◽  
pp. 1002-1009 ◽  
Author(s):  
Dunk Porterfield ◽  
John W. Wilcut ◽  
Jerry W. Wells ◽  
Scott B. Clewis
Keyword(s):  
North Carolina ◽  
Weed Control ◽  
Weed Management ◽  
Field Studies ◽  
Palmer Amaranth ◽  
Management Systems ◽  
Weed Species ◽  
Crop Tolerance ◽  
Prickly Sida ◽  
Smooth Pigweed

Field studies conducted at three locations in North Carolina in 1998 and 1999 evaluated crop tolerance, weed control, and yield with CGA-362622 alone and in combination with various weed management systems in transgenic and nontransgenic cotton systems. The herbicide systems used bromoxynil, CGA-362622, glyphosate, and pyrithiobac applied alone early postemergence (EPOST) or mixtures of CGA-362622 plus bromoxynil, glyphosate, or pyrithiobac applied EPOST. Trifluralin preplant incorporated followed by (fb) fluometuron preemergence (PRE) alone or fb a late POST–directed (LAYBY) treatment of prometryn plus MSMA controlled all the weed species present less than 90%. Herbicide systems that included soil-applied and LAYBY herbicides plus glyphosate EPOST or mixtures of CGA-362622 EPOST plus bromoxynil, glyphosate, or pyrithiobac controlled broadleaf signalgrass, entireleaf morningglory, large crabgrass, Palmer amaranth, prickly sida, sicklepod, and smooth pigweed at least 90%. Only cotton treated with these herbicide systems yielded equivalent to the weed-free check for each cultivar. Bromoxynil systems did not control Palmer amaranth and sicklepod, pyrithiobac systems did not control sicklepod, and CGA-362622 systems did not control prickly sida.

Mustard tolerance to clopyralid applied alone or with ethametsulfuron

1994 ◽  
Vol 74 (3) ◽  
pp. 635-641
Author(s):  
H. A. Loeppky ◽  
R. E. Blackshaw
Keyword(s):  
Weed Control ◽  
Oil Content ◽  
Growth Stage ◽  
Field Studies ◽  
The Other ◽  
Yellow Mustard ◽  
Crop Tolerance ◽  
Drought Tolerant ◽  
Control Limits ◽  
Oriental Mustard

Mustard is a drought-tolerant crop well adapted to the Brown and Dark Brown soils of the Prairies; however, lack of broad-leaved weed control limits production. Two field studies were conducted at Indian Head, Saskatchewan and Lethbridge, Alberta to determine the response of brown and oriental mustard (Brassica juncea (L.) Coss), and yellow mustard (B. hirta Moench) to clopyralid. Clopyralid was applied at 0.10, 0.15, 0.20, 0.30, 0.60 kg a.i. ha−1 at the 4- or 10-leaf stage in one experiment. The other was a factorial experiment of clopyralid at 0.10, 0.20, and 0.30 kg a.i. ha−1 with ethametsulfuron at 0.01, 0.02, and 0.03 kg a.i. ha−1. Clopyralid applied at 0.15 kg a.i. ha−1, the lowest rate at which it is registered for weed control in canola, resulted in brown mustard yield reductions of 21%, oriental mustard yield reductions of 23% and yellow mustard yield reductions of 9% over 5 site years. This rate of clopyralid applied with ethametsulfuron reduced brown, oriental and yellow mustard yield by 30, 33 and 8%, respectively. Oil content was also reduced by clopyralid. Clopyralid cannot be used for weed control in mustards. Key words: Crop tolerance, growth stage, clopyralid, ethametsulfuron, seed yield, oil content

scholarly journals EXPOSURE TO CHILLING TEMPERATURES REDUCES GROWTH AND YIELD OF `SUPERSTAR' MUSKMELON

HortScience ◽  
1994 ◽  
Vol 29 (7) ◽  
pp. 734a-734
Author(s):  
W.D. Scott
Keyword(s):  
Leaf Area ◽  
Significant Interaction ◽  
Dry Weight ◽  
Field Studies ◽  
Growth And Yield ◽  
Single Plant ◽  
Growth Data ◽  
Flower Number ◽  
Chilling Temperatures ◽  
Plastic Containers

Greenhouse and field studies were conducted using research coolers to expose 4 week old `Superstar' muskmelons, planted into 1 liter plastic containers, to chilling temperatures. Temperatures of 1, 5, & 9 °C were arranged in factorial combination with lengths of exposures 6, 12, & 24 hours and number of exposures 1, 3, & 5. In the Greenhouse studies single plant experimental units were allowed to grow for 2 weeks following application of the chilling treatments, then growth data was taken. In field studies, exposed muskmelons were planted into 8 plants/plot units when all plants had received chilling treatments. Leaf area and plant dry weight of `Superstar' melons were significantly reduced by both the interaction of temperature and length of exposure and times exposed and temperature, with dramatic reductions in leaf area occurring at 24 hours of exposure or 5 times exposed at 1 °C. A significant interaction was found between times exposed or length of exposure and temperature on vine length, flower number and type measurements taken 4 weeks after chilled transplants were established in the field. Additionally, fruit number and mean melon weight were reduced by ether exposure to 10C, exposure of 24 hours or 3 times exposed.

scholarly journals SPUR PRUNING `DELICIOUS' APPLE TREES

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1102c-1102
Author(s):  
Richard Marini
Keyword(s):  
Leaf Area ◽  
Dry Weight ◽  
Fruit Weight ◽  
Apple Trees ◽  
Weight Yield ◽  
Spur Length ◽  
Leaf Dry Weight ◽  
All Treatment

Twenty-eight-year-old `Starkrimson Delicious' trees were spur pruned in 1986 and 1987 and/or treated with BA + GA4+7 in 1986 in an attempt to improve spur growth and fruit weight. Yield, fruit weight, and spur quality characters were recorded for 1986-1989. All treatment combinations failed to improve yield or fruit weight. Although spur-pruning improved spur length, spur bud diameter, leaf area per spur and leaf dry weight per spur, fruit weight was not improved. BA + GA4+7 reduced yield and fruit weight, and increased the number of pygmy fruit in 1986, but had little effect on fruiting for the three years after treatment.

scholarly journals The Effect of Composted Organic Wastes on Weed Control Provided by Preemergence Herbicides

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 470E-470
Author(s):  
Jennifer A. Johnson ◽  
Larry Kuhns ◽  
Tracey Harpster
Keyword(s):  
Organic Matter ◽  
Sewage Sludge ◽  
Weed Control ◽  
Dry Weight ◽  
Field Studies ◽  
Silty Clay ◽  
Yard Waste ◽  
Application Rates ◽  
Preemergence Herbicides ◽  
Composted Sewage Sludge

Community waste management programs that include the composting of sewage sludge and yard wastes have become a necessity. Using these composts provides many benefits; however, increased levels of organic matter may reduce the effectiveness of preemergence herbicides. Determining how herbicide application rates may need to be adjusted when composted waste is incorporated into the soil may permit the use of these amendments without any decrease in weed control. This experiment examined the effect of two types of compost (composted sewage sludge and composted yard waste) on the weed control provided by four preemergence herbicides. The soil was a Hagerstown silt loam amended with 10%, 20%, or 30% compost by volume. Each mix was placed in half-gallon cardboard milk cartons. The cartons were seeded at 1/2 and 1/4 inches with a mixture of broadleaved weeds and grasses. Each soil mix was treated with simazine, oxyfluorfen, oryzalin, and metolachlor at two rates. Control was evaluated both visually by number and by the dry weight of the harvested weeds. Preliminary results indicate composted sewage sludge causes a greater reduction in herbicide efficacy than composted yard waste. Oryzalin and metolachlor were affected less than oxyfluorfen or simazine. The experiment was repeated using lower application rates. In one replication the soil mixes from the previous experiment were used. The second replication used a Hagerstown silty clay loam soil with fresh compost. The results of this experiment will provide preliminary information for future field studies designed to determine if the application rates of preemergence herbicides need to be adjusted when fields are amended with composted organic matter.

Weed competition in maize (Zea mays L.) as a function of the timing of hand-hoeing weed control in the southern Guinea savanna zone of Nigeria

2012 ◽  
Vol 60 (3) ◽  
pp. 257-264 ◽  
Author(s):  
F. Takim
Keyword(s):  
Grain Yield ◽  
Weed Control ◽  
Seedling Emergence ◽  
Dry Weight ◽  
Field Studies ◽  
Growth And Yield ◽  
Weed Competition ◽  
Maize Crop ◽  
Weed Interference ◽  
The University

Field studies were conducted in 2010 and 2011 at the Teaching and Research Farm of the University of Ilorin, Nigeria (9°29′ N, 4°35′ E) to evaluate the effect of early weed competition on the growth and yield of maize. The experiment was designed as a randomized complete block (RCBD) with a split-plot arrangement and three replications. The main plots consisted of three weed control treatments included weedy (no herbicide), grass weeds (pre-emergence atrazine) and broadleaf weeds (pre-emergence metolachlor), while the sub-plots consisted of six durations of weed infestation (3, 4, 5, 6, 7 and 8 weeks after emergence). The pre-emergence herbicides had a greater effect on weed density and weed dry weight. Weed seedling emergence and weed dry weight increased significantly with an increase in the duration of weed interference. The grasses and broadleaf weeds had a similar influence on the growth and grain yield of maize. Three to five weeks of weed interference gave similar grain yields, which were significantly higher than those obtained in plots that had 6-8 weeks of weed interference. These results suggest that the maize crop must be kept free of weeds for 6-8 weeks after the application of pre-emergence herbicide to minimize weed-crop competition and harvest a good grain yield.

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