scholarly journals Effect of Purple Nutsedge (Cyperus rotundus) Population Densities on Onion (Allium cepa) as Influenced by Nitrogen in the Eastern Province of Sri Lanka

2011 ◽  
Vol 22 (4) ◽  
pp. 348
Author(s):  
T Geretharan ◽  
UR Sangakkara ◽  
V Arulnandhy
Keyword(s):  
Sri Lanka ◽  
Allium Cepa ◽  
Cyperus Rotundus ◽  
Population Densities ◽  
Eastern Province ◽  
Purple Nutsedge

Biocontrol of Purple Nutsedge byBactra verutanaZeller in a Greenhouse

Weed Science ◽  
1977 ◽  
Vol 25 (1) ◽  
pp. 13-17 ◽  
Author(s):  
K.E. Frick ◽  
P.C. Quimby
Keyword(s):  
Osmotic Stress ◽  
Cucumis Sativus ◽  
Allium Cepa ◽  
Nitrogen Deficiency ◽  
Dry Weight ◽  
Stress Conditions ◽  
Cyperus Rotundus ◽  
Plant Weight ◽  
Purple Nutsedge ◽  
Degree Of Control

The degree of control of purple nutsedge (Cyperus rotundusL.) provided byBactra verutanaZeller, a native moth, was evaluated for various stress conditions. Two, three, or four weekly infestations each with three larvae per live shoot, reduced purple nutsedge dry weight an average 77% compared with an average 55% for one infestation. Eight weekly infestations reduced plant dry weight 98%. Neither caging of the larvae on the plants nor osmotic stress with NaCl to −8 bars influenced larval efficacy, but nitrogen deficiency did reduce the effect of the larvae about 75%. Purple nutsedge had no effect on the dry weight of cucumber (Cucumis sativusL., ‘Straight Eight’) after 1 month, whether larvae were or were not present. Purple nutsedge did reduce the plant dry weight of okra (Abelmoschus esculentus(L.) Moench, ‘Clemson Spineless’) 64%, but repeated (eight) weekly infestations of larvae gave a plant weight of okra equal to that of okra grown without purple nutsedge. Purple nutsedge reduced the bulb and root dry weight of onion (Allium cepaL., ‘Big Valley’) 37%, but repeated weekly infestations of larvae gave onion growth equal to that of onion grown without purple nutsedge.

Effects of Purple Nutsedge (Cyperus rotundus) on Tomato (Lycopersicon esculentum) and Bell Pepper (Capsicum annuum) Vegetative Growth and Fruit Yield

1997 ◽  
Vol 11 (4) ◽  
pp. 672-676 ◽  
Author(s):  
Jose P. Morales-Payan ◽  
Bielinski M. Santos ◽  
William M. Stall ◽  
Thomas A. Bewick
Keyword(s):  
Dry Weight ◽  
Fruit Yield ◽  
Cyperus Rotundus ◽  
Bell Pepper ◽  
Initial Population ◽  
Yield Losses ◽  
Population Densities ◽  
Purple Nutsedge ◽  
Shoot Dry Weight ◽  
Percentage Unit

Additive series experiments were conducted under greenhouse conditions to determine the effect of season-long interference of different initial population densities of purple nutsedge on the shoot dry weight and fruit yield of tomato and bell pepper. Purple nutsedge densities up to 200 plants/m2linearly reduced shoot dry weight at flowering and fruit yield of both crops as weed density increased. Both variables were directly correlated, and for each percentage unit of tomato shoot dry weight loss at flowering, fruit yield was reduced 1.24 units, whereas for bell pepper this relationship was 1 to 2.01. Total shoot and tuber biomass of purple nutsedge increased as density increased. The presence of either crop caused a decline in the total shoot dry weight accumulation of purple nutsedge, with tomato producing a higher degree of loss than bell pepper to the weed. Fruit yield losses due to purple nutsedge interference reached 44% for tomato and 32% for bell pepper.

scholarly journals Effect of Purple Nutsedge (Cyperus rotundus) Population Densities on the Growth of Transplants of Three Papaya (Carica papaya) Cultivars

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 431E-431
Author(s):  
J.P. Morales-Payan ◽  
W.M. Stall
Keyword(s):  
Carica Papaya ◽  
Dry Weight ◽  
Cyperus Rotundus ◽  
Initial Population ◽  
Santo Domingo ◽  
Population Densities ◽  
Purple Nutsedge ◽  
Shoot Dry Weight ◽  
Weight Losses ◽  
Significant Difference

Nursery experiments were conducted in Santo Domingo, Dominican Republic, to determine the effect of increasing population densities of purple nutsedge (Cyperus rotundus) on the growth of papaya (Carica papaya) transplants. Seeds of `Sunrise Solo', `Red Lady', and `Cartagena Ombligua' were separately sown in plastic 12 × 15-cm containers filled with a 1:1 mixture of sand and loamy soil. Viable purple nutsedge tubers were planted 5 cm apart from the papaya seeds. The purple nutsedge initial population densities were 0, 1, 2, 4, and 6 tubers per container. The crop and the weed were sown the same day and allowed to interfere during 6 weeks. Purple nutsedge density had a significant effect on the height, leaf area, and shoot dry weight of the three papaya cultivars. There was no significant difference in the response of the three papaya cultivars to purple nutsedge densities. In general, as purple nutsedge density increased, papaya growth decreased. Nutsedge interference caused papaya shoot dry weight losses of 15% at the density of one plant per container and 73% at six plants per container.

scholarly journals Effect of Purple Nutsedge (Cyperus rotundus) Population Densities on the Yield of Eggplant (Solanum melongena)

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 431D-431
Author(s):  
J.P. Morales-Payan ◽  
W.M. Stall
Keyword(s):  
Field Experiments ◽  
Yield Loss ◽  
Solanum Melongena ◽  
Fruit Yield ◽  
Cyperus Rotundus ◽  
Initial Population ◽  
Santo Domingo ◽  
Population Densities ◽  
Purple Nutsedge ◽  
Linear Decline

Field experiments were conducted in Santo Domingo, Dominican Republic, to determine the effect of increasing population densities of purple nutsedge (Cyperus rotundus) on the yield of eggplant (Solanum melongena). Purple nutsedge populations were established by transplanting viable tubers on 1-m-wide soil beds previously fumigated to suppress volunteer weeds. Nutsedge densities were 0, 50, 100, 150, and 200 plants (tubers) per m2. `Jira' eggplants and purple nutsedge were transplanted the same day and were allowed to interfere season-long. Purple nutsedge initial population densities of up to 100 plants per m2 did not significantly affect the fruit yield of `Jira' eggplants. However, nutsedge densities between 100 and 200 plants per m2 had a significant impact on eggplant yield, causing a linear decline in fruit yield as purple nutsedge density increased. Eggplant fruit yield loss was 22.3% at the density of 200 nutsedge plants per m2.

Interference of Purple Nutsedge (Cyperus rotundus) Population Densities on Bell Pepper (Capsicum annuum) Yield as Influenced by Nitrogen

1998 ◽  
Vol 12 (2) ◽  
pp. 230-234 ◽  
Author(s):  
Jose P. Morales-Payan ◽  
Bielinski M. Santos ◽  
William M. Stall ◽  
Thomas A. Bewick
Keyword(s):  
Population Density ◽  
Fruit Yield ◽  
Cyperus Rotundus ◽  
Bell Pepper ◽  
Yield Reduction ◽  
Linear Regression Models ◽  
Population Densities ◽  
Purple Nutsedge ◽  
Pepper Fruit ◽  
N Rates

Additive series studies were conducted under greenhouse conditions to determine the effects of nitrogen (N) rate and purple nutsedge densities on the yield of ‘California Wonder’ bell pepper. Initial densities of purple nutsedge were 0, 100, 200, and 300 plants/m2. Nitrogen was applied at 70, 140, and 210 kg/ha. Plants were allowed to interfere for 10 wk. There were significant purple nutsedge population density by N rate interactions on bell pepper fruit yield. At 70 kg N/ha, no significant effect of weed population densities was found on fruit yield, whereas at the rates of 140 and 210 kg N/ha there were significant nutsedge density effects. As N rates and nutsedge densities increased, so did purple nutsedge biomass. Linear regression models described the interference. Bell pepper fruit yield reduction was 73% at 210 kg N/ha with an initial nutsedge population density of 300 plants/m2.

Enhancement of Herbicide Activity with an Isoparaffinic Oil Carrier

Weed Science ◽  
1971 ◽  
Vol 19 (6) ◽  
pp. 701-705 ◽  
Author(s):  
R. J. Burr ◽  
G. F. Warren
Keyword(s):  
Acetic Acid ◽  
Cyperus Rotundus ◽  
Setaria Viridis ◽  
Ipomoea Hederacea ◽  
Purple Nutsedge ◽  
Green Foxtail ◽  
Herbicide Activity ◽  
Dichlorophenoxy Acetic Acid ◽  
Agropyron Repens

Several herbicides were tested in the greenhouse on ivyleaf morningglory (Ipomoea hederacea(L.) Jacq.), green foxtail (Setaria viridis(L.) Beauv.), purple nutsedge (Cyperus rotundusL.), and quackgrass (Agropyron repens(L.) Beauv.) to determine the degree of enhancement in activity that could be obtained with an isoparaffinic oil carrier applied at 140 L/ha. The enhancement varied with the herbicide and with the species, ranging from 16-fold enhancement with 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine (atrazine) and 2-sec-butyl-4,6-dinitrophenol (dinoseb) on ivyleaf morningglory to no enhancement of atrazine activity on purple nutsedge and quackgrass or (2,4-dichlorophenoxy)acetic acid (2,4-D) activity on quackgrass and ivyleaf morningglory. An oil adjuvant was less effective in enhancing dinoseb and 3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea (linuron) activity than was the isoparaffinic oil carrier. Also, the isoparaffinic oil carrier emulsified in water was less effective than the undiluted oil in enhancing dinoseb activity on green foxtail, even though equal volumes of the isoparaffinic oil were applied.

Field Efficacy ofDactylaria higginsiias a Bioherbicide for the Control of Purple Nutsedge (Cyperus rotundus)1

2000 ◽  
Vol 14 (1) ◽  
pp. 1-6 ◽  
Author(s):  
JUGAH B. KADIR ◽  
R. CHARUDATTAN ◽  
WILLIAM M. STALL ◽  
BARRY J. BRECKE
Keyword(s):  
Cyperus Rotundus ◽  
Purple Nutsedge ◽  
Field Efficacy

scholarly journals Growth and Development of Purple Nutsedge Based on Days or Thermal Units

2015 ◽  
Vol 33 (2) ◽  
pp. 165-173 ◽  
Author(s):  
R.S.O. Lima ◽  
E.C.R. Machado ◽  
A.P.P. Silva ◽  
B.S. Marques ◽  
M.F. Gonçalves ◽  
...  
Keyword(s):  
Plant Growth ◽  
Mathematical Models ◽  
Growth And Development ◽  
Dry Matter ◽  
Cyperus Rotundus ◽  
Growing Degree Days ◽  
Plant Growth And Development ◽  
Degree Days ◽  
Purple Nutsedge ◽  
Independent Trials

This work was carried out with the objective of elaborating mathematical models to predict growth and development of purple nutsedge (Cyperus rotundus) based on days or accumulated thermal units (growing degree days). Thus, two independent trials were developed, the first with a decreasing photoperiod (March to July) and the second with an increasing photoperiod (August to November). In each trial, ten assessments of plant growth and development were performed, quantifying total dry matter and the species phenology. After that, phenology was fit to first degree equations, considering individual trials or their grouping. In the same way, the total dry matter was fit to logistic-type models. In all regressions four temporal scales possibilities were assessed for the x axis: accumulated days or growing degree days (GDD) with base temperatures (Tb) of 10, 12 and 15 oC. For both photoperiod conditions, growth and development of purple nutsedge were adequately fit to prediction mathematical models based on accumulated thermal units, highlighting Tb = 12 oC. Considering GDD calculated with Tb = 12 oC, purple nutsedge phenology may be predicted by y = 0.113x, while species growth may be predicted by y = 37.678/(1+(x/509.353)-7.047).

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