Smooth Pigweed (Amaranthus hybridusL.) and Livid Amaranth (Amaranthus lividus) Interference with Cucumber (Cucumis sativus)

2006 ◽  
Vol 20 (1) ◽  
pp. 227-231 ◽  
Author(s):  
Adrian D. Berry ◽  
William M. Stall ◽  
B. Rathinasabapathi ◽  
Gregory E. Macdonald ◽  
R. Charudattan
Keyword(s):  
Dry Weight ◽  
Field Studies ◽  
Fruit Yield ◽  
Yield Reduction ◽  
Cucumber Plant ◽  
Weed Density ◽  
Weed Interference ◽  
Shoot Dry Weight ◽  
Cucumber Fruit ◽  
Smooth Pigweed

Field studies were conducted to determine the effect of season-long interference of smooth pigweed or livid amaranth on the shoot dry weight and fruit yield of cucumber. Smooth pigweed or livid amaranth densities as low as 1 to 2 weeds per m2caused a 10% yield reduction in cucumber. The biological threshold of smooth pigweed or livid amaranth with cucumber is between 6 to 8 weeds per m2. Consequently, weed interference resulted in a reduction in cucumber fruit yield. Smooth pigweed, livid amaranth, and cucumber plant dry weight decreased as weed density increased. Evaluation of smooth pigweed, livid amaranth, and cucumber mean dry weights in interspecific competition studies indicated that cucumber reduced the dry weight of both species of amaranths.

Interference of Wild Poinsettia (Euphorbia heterophylla) with Soybean (Glycine max)

1994 ◽  
Vol 8 (4) ◽  
pp. 679-683 ◽  
Author(s):  
Teresa S. Willard ◽  
James L. Griffin ◽  
Daniel B. Reynolds ◽  
Arnold M. Saxton
Keyword(s):  
Glycine Max ◽  
Dry Weight ◽  
Growing Season ◽  
Field Studies ◽  
Yield Reduction ◽  
Soybean Yield ◽  
Weed Interference ◽  
Soybean Canopy ◽  
Area Of Influence

Field-studies were conducted over two years to determine the area of influence and duration of interference of wild poinsettia in soybean. Soybean canopy width averaged across years was reduced approximately 10% beginning at 6 wk of interference for both the 0- to 10-and 10-to 20-cm distances from the weed. Soybean dry weights decreased from 14 to 38% within 20 cm of the weed for 12 through 18 wk of interference. In 1990, soybean yield within 10 cm of wild poinsettia was similar to distances of 10 to 20 and 20 to 40 cm, but was less than that for distances greater than 40 cm from the weed. Weed interference resulted in a 9.5% yield reduction in the 0- to 10-cm distance when compared with the 80-to 100-cm distance. In contrast, yield of soybean in 1991 growing within 10 cm of the weed was less than at greater distances, corresponding to an 18% yield reduction when compared with 80 to 100 cm. Differences in wild poinsettia dry weights when growing alone and when growing within the soybean row occurred after 6 and 8 wk of interference in 1990 and 1991, respectively. In 1991 when rainfall during the growing season was twice that of the previous year, canopy width and dry weight of wild poinsettia growing within the soybean row were reduced an average of 57 and 82%, respectively, compared with weeds growing alone.

Effect of bicyclopyrone herbicide on sweetpotato and Palmer amaranth (Amaranthus palmeri)

2020 ◽  
Vol 34 (4) ◽  
pp. 552-559
Author(s):  
Jennifer J. Lindley ◽  
Katherine M. Jennings ◽  
David W. Monks ◽  
Sushila Chaudhari ◽  
Jonathan R. Schultheis ◽  
...  
Keyword(s):  
Dry Weight ◽  
Field Studies ◽  
Palmer Amaranth ◽  
Yield Reduction ◽  
Amaranthus Palmeri ◽  
Marketable Yield ◽  
Management Options ◽  
Application Timing ◽  
Shoot Dry Weight ◽  
Plant Injury

AbstractManagement options are needed to limit sweetpotato yield loss due to weeds. Greenhouse studies were conducted in 2018 in Greensboro, NC, and in the field from 2016 to 2018 in Clinton, NC, to evaluate the effect of bicyclopyrone on sweetpotato and Palmer amaranth (field only). In greenhouse studies, Covington and NC04-531 clones were treated with bicyclopyrone (0, 25, 50, 100, or 150 g ai ha−1) either preplant (PP; i.e., immediately before transplanting) or post-transplant (PT; i.e., on the same day after transplanting). Sweetpotato plant injury and stunting increased, and vine length and shoot dry weight decreased with increasing rate of bicyclopyrone regardless of clone or application timing. In field studies, Beauregard (2016) or Covington (2017 and 2018) sweetpotato clones were treated with bicyclopyrone at 50 g ha−1 PP, flumioxazin at 107 g ai ha−1 PP, bicyclopyrone at 50 or 100 g ha−1 PP followed by (fb) S-metolachlor at 800 g ai ha−1 PT, flumioxazin at 107 g ha−1 PP fb S-metolachlor at 800 g ha−1 PT, flumioxazin at 107 g ha−1 PP fb S-metolachlor at 800 g ha−1 PT fb bicyclopyrone at 50 g ha−1 PT-directed, and clomazone at 420 g ai ha−1 PP fb S-metolachlor at 800 g ha−1 PT. Bicyclopyrone PP at 100 g ha−1 fb S-metolachlor PT caused 33% or greater crop stunting and 44% or greater marketable yield reduction compared with the weed-free check in 2016 (Beauregard) and 2017 (Covington). Bicyclopyrone PP at 50 g ha−1 alone or fb S-metolachlor PT resulted in 12% or less injury and similar no. 1 and jumbo yields as the weed-free check in 2 of 3 yr. Injury to Covington from bicyclopyrone PT-directed was 4% or less at 4 or 5 wk after transplanting and marketable yield was similar to that of the weed-free check in 2017 and 2018.

scholarly journals No Evidence of Adverse Effects on Germination, Emergence, and Fruit Yield due to Space Exposure of Tomato Seeds

1996 ◽  
Vol 121 (3) ◽  
pp. 414-418 ◽  
Author(s):  
Brian A. Kahn ◽  
Peter J. Stoffella
Keyword(s):  
Adverse Effects ◽  
Outer Space ◽  
Dry Weight ◽  
Fruit Yield ◽  
Control Seed ◽  
Shoot Dry Weight ◽  
Tomato Seeds ◽  
Long Duration ◽  
Main Effect ◽  
Mean Time

Seeds of `Rutgers California Supreme' tomato (Lycopersicon esculentum Mill.) were exposed to outer space conditions aboard the long duration exposure facility (LDEF) satellite in the space exposed experiment developed for students (SEEDS) project of the National Aeronautics and Space Administration (NASA). Seeds aboard the LDEF were packed in dacron bags forming four layers per sealed canister. Some of these seeds were used in Oklahoma and Florida for studies of germination, emergence, and fruit yield. Among all measured variables in three experiments, there was only one significant main effect of canister 2 versus canister 7 (for mean time to germination) and only one main effect of layer (for seedling shoot dry weight). There also were only two inconsistent canister x layer interactions in the germination tests. The contrast of Earth-based control seed versus space-exposed seed was significant four times: in Oklahoma in 1991 the mean time to germination of space-exposed seeds and the days to 50% of final germination were 0.7 days less than for Earth-based seeds, and in Florida in 1992 seedling percent emergence and shoot dry weight were increased by space exposure. Fruit yield and marketability were unaffected in plants grown from space-exposed seeds. These results support student findings from the SEEDS project, and provide evidence that tomato seeds can survive in space for several years without adverse effects on germination, emergence, and fruit yield.

Spring Wheat (Triticum aestivum)Cultivar Responses to Trifluralin and Postemergence Herbicides

1995 ◽  
Vol 9 (2) ◽  
pp. 352-355 ◽  
Author(s):  
Sharon A. Clay ◽  
Jim F. Gaffney ◽  
Leon J. Wrage
Keyword(s):  
Spring Wheat ◽  
Plant Stress ◽  
Dry Weight ◽  
Field Studies ◽  
Growth And Yield ◽  
Hard Red Spring Wheat ◽  
Wheat Field ◽  
Shoot Dry Weight ◽  
Cultivar Responses ◽  
Postemergence Herbicides

Trifluralin is used for weed control in wheat but may reduce vegetative growth and yield. Postemergence (POST) herbicides may cause additional plant stress to trifluralin-stressed wheat. Field studies at Groton, SD in 1991 and 1992 and at Highmore, SD in 1992 evaluated the effects of 2,4-D-amine, difenzoquat, metsulfuron, and a combination of fenoxaprop-ethyl + 2,4-D-ester + MCPA-ester on hard red spring wheat cultivars ‘2375,’ ‘Prospect,’ and ‘Butte 86’ seeded in areas treated with preplant incorporated trifluralin either in the spring before seeding (0.56 kg ai/ha) or the previous year (1.12 or 2.24 kg ai/ha). Trifluralin applied alone in the spring, and followed by some POST herbicides, reduced shoot dry weight and grain yield. Trifluralin reduced the yield of Prospect the most and the yield of 2375 the least. Yields of trifluralin-treated wheat were reduced 23% by metsulfuron and 14% by fenoxaprop-ethyl + 2,4-D + MCPA compared to yields of wheat treated with only the respective POST herbicide. Yields were not reduced with any trifluralin-POST herbicide combination when trifluralin was applied a year prior to seeding wheat.

Effects of Barnyardgrass (Echinochloa crus-galli) on Growth, Yield, and Nutrient Status of Transplanted Tomato (Lycopersicon esculentum)

Weed Science ◽  
1988 ◽  
Vol 36 (6) ◽  
pp. 775-778 ◽  
Author(s):  
Prasanta C. Bhowmik ◽  
Krishna N. Reddy
Keyword(s):  
Unit Area ◽  
Tomato Fruit ◽  
Growth Yield ◽  
Dry Weight ◽  
Nutrient Status ◽  
Field Studies ◽  
Fruit Weight ◽  
Fresh Weight ◽  
Shoot Dry Weight ◽  
Marketable Fruit

Field studies were conducted to determine the effects of various barnyardgrass populations on growth, yield, and nutrient concentration of transplanted “Jetstar’ tomato. Barnyardgrass densities at 16, 32, and 64 plants/m tomato row were tested in 1982 and 1983. Barnyardgrass shoot fresh weights/unit area increased as density increased. Fresh weight of barnyardgrass shoots ranged from 17 100 kg/ha at 16 plants/m of row to 35 500 kg/ha at 64 plants/m of row. At the vegetative stage, tomato shoot dry weight was unaffected by barnyardgrass. As crop growth progressed, tomato shoot dry weight decreased at all barnyardgrass densities. Season-long interference of barnyardgrass reduced marketable tomato fruit number and fruit weight at all densities compared to weed-free plots. Reductions in marketable fruit weight ranged from 26% to 16 plants/m row to 84% at 64 plants/m row. In 1982, concentrations of N, P, K, Ca, and Mg in tomato shoots were unaffected by season-long interference of barnyardgrass at all densities. However, in 1983, concentrations of N and K decreased and concentration of P increased in tomato leaves as the density of barnyardgrass increased. Concentrations of Ca and Mg in tomato leaves were unaltered by barnyardgrass density.

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.

Time of Removal of Crownbeard (Verbesina encelioides) on Peanut Yield

2005 ◽  
Vol 19 (2) ◽  
pp. 380-384 ◽  
Author(s):  
Rodney L. Farris ◽  
Cody J. Gray ◽  
Don S. Murray ◽  
Laval M. Verhalen
Keyword(s):  
Natural Population ◽  
Field Experiments ◽  
Yield Reduction ◽  
Weed Density ◽  
Weed Interference ◽  
Weed Growth ◽  
Poor Predictor ◽  
Verbesina Encelioides ◽  
Shell Peanut ◽  
Weed Removal

Field experiments were conducted in southwestern Oklahoma near Colony in 2000 and near Ft. Cobb in 2001 to quantify the effect of time of removal of a natural population of crownbeard on peanut yield. Weed densities and dry weed weights were measured at eight weed-removal times, and in-shell peanut yields were determined at harvest. Crownbeard was removed at 0 (the weed-free check), 4, 6, 8, 10, 12, 14, and 16 wk (full season) after crop emergence (WAE). Weed density was a poor predictor for dry weed weight and peanut yield; however, dry weed weight and time of removal were good predictors for peanut yield. Weed growth was minimal up to 4 WAE and increased linearly after that time. For each week of weed growth, a 0.52 kg/plot increase in dry weed weight was measured. Peanut yield decreased linearly because of crownbeard competition. For each kilogram per plot increase in dry weed weight, a 129 kg/ha or 5.1% peanut yield reduction took place. For each week of weed interference, a 75 kg/ha or 2.8% peanut yield reduction occurred. Crownbeard removal by or before 4 WAE will minimize losses in peanut yield because of interference.

scholarly journals Household Detergent on Tomato: Phytotoxicity and Toxicity to Silverleaf Whitefly

HortScience ◽  
1995 ◽  
Vol 30 (7) ◽  
pp. 1406-1409 ◽  
Author(s):  
C.S. Vavrina ◽  
P.A. Stansly ◽  
T.X. Liu
Keyword(s):  
Dry Weight ◽  
Field Studies ◽  
Yield Reduction ◽  
Silverleaf Whitefly ◽  
Fresh Market ◽  
Fruit Maturity ◽  
Household Detergent ◽  
Household Detergents ◽  
Rate Frequency ◽  
Laboratory Bioassays

Household detergents were evaluated in field studies on fresh-market tomato (Lycopersicon esculentum Mill.) for insecticidal and phytotoxic effects. Laboratory bioassays were used to examine the toxicity of a household liquid dish detergent on small nymphs of silverleaf whitefly, Bemisia argentifolii Bellows and Perring. The detergents tested proved to be more toxic to whitefly nymphs than the commercial insecticidal soap. Detergent treatments were applied to tomato with a commercial high pressure hydraulic sprayer at 0%, 1%, 2%, 4%, and 8% (by volume) initially and at 0%, 0.25%, 0.5%, 1.0%, and 2.0% (by volume) in subsequent tests. As detergent rate, frequency of application, or both increased, plant dry weight accumulation and fruit yield decreased. Applying detergent also increased time to fruit maturity. A once-a-week application of 0.25% to 0.5% detergent initially applied 2 weeks after transplanting alleviated phytotoxicity and yield reduction problems.

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.

Spotted Spurge (Euphorbia maculata) Interference with Cotton (Gossypium hirsutum)

Weed Science ◽  
1994 ◽  
Vol 42 (4) ◽  
pp. 553-555 ◽  
Author(s):  
Mohammad T. Bararpour ◽  
Ronald E. Talbert ◽  
Robert E. Frans
Keyword(s):  
Linear Relationship ◽  
Dry Weight ◽  
Field Studies ◽  
Yield Reduction ◽  
Cotton Yield ◽  
Seed Cotton ◽  
Percent Reduction ◽  
Cotton Boll ◽  
Positive Linear Relationship ◽  
Seed Cotton Yield

Field studies were conducted from 1988 through 1990 in Fayetteville, AR, to measure competitiveness of spotted spurge in cotton. Population levels were established by transplanting seedlings from other field areas. There was a positive linear relationship between cotton boll numbers and seed cotton yield. Percent reduction in cotton height, leaf area, dry weight, boll numbers, and seed cotton yield increased as spotted spurge densities increased. Seed cotton yield reduction was 47, 57, and 85% for spotted spurge densities of 5, 10, and 50 spotted spurge plants m–1of row.

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