Critical Period of Interference between American Black Nightshade and Triploid Watermelon

2010 ◽  
Vol 24 (3) ◽  
pp. 397-400 ◽  
Author(s):  
Joshua I. Adkins ◽  
William M. Stall ◽  
Bielinski M. Santos ◽  
Stephen M. Olson ◽  
Jason A. Ferrell
Keyword(s):  
Critical Period ◽  
Yield Loss ◽  
Field Trials ◽  
Black Nightshade ◽  
Maximum Period ◽  
American Black ◽  
Triploid Watermelon

Field trials were conducted in the spring of 2007 and 2008 to investigate the critical period of interference between American black nightshade and triploid watermelon. To determine the critical period, the maximum period of competition and minimum weed-free period were examined. American black nightshade (2 plants m−2) was established into watermelon plots at watermelon transplanting and removed at 0, 1, 2, 3, 4, and 5 wk after transplanting to determine the maximum period of competition. American black nightshade (2 plants m−2) was established into watermelon plots at 0, 1, 2, 3, 4, and 5 wk after transplanting and remained until watermelon harvest to determine the minimum weed-free period. To avoid yield loss from exceeding 10% of a crop grown weed-free, the maximum period of competition and minimum weed-free period were found to be 3.9 and 3.6 weeks after transplanting, respectively. Therefore, if American black nightshade is controlled at any time during the critical period of 3.6 to 3.9 wk after transplanting, yield loss should not exceed 10% of a crop grown weed-free.

Critical Period of Quackgrass (Elytrigia repens) Removal in Potatoes (Solanum tuberosum)

Weed Science ◽  
1994 ◽  
Vol 42 (4) ◽  
pp. 528-533 ◽  
Author(s):  
R. Baziramakenga ◽  
Gilles D. Leroux
Keyword(s):  
Critical Period ◽  
Yield Loss ◽  
Field Trials ◽  
Quebec City ◽  
Critical Periods ◽  
Marketable Yield ◽  
Elytrigia Repens ◽  
Medium Level ◽  
High Level ◽  
Loss Level

Field trials were carried out in 1989 and 1990 at St-Augustin, near Québec City, Canada, to determine the critical periods of quackgrass control in potato submitted to three levels of infestation. Potato yield losses due to quackgrass interference increased with quackgrass infestation and length of duration of interference. Quackgrass interference influenced marketable tuber yields more than total tuber yields. Duration of the critical period varied depending on the level of quackgrass infestation and year. Based on an arbitrary 5% level of marketable yield loss, the critical period started at ca. 15 days after emergence (DAE) of potato at low level of infestation, and at ca. 3 DAE at medium level of infestation. At high level of infestation, the critical period began prior to the emergence of potato. The end of the critical period of quackgrass removal was extremely variable across quackgrass infestation level and year and ranged from 23 to 68 DAE of potato at a 5 % yield loss level. It appears that onset of interference varied less than the end of it, indicating that early quackgrass control is necessary to prevent yield loss.

The Effects of American Black Nightshade (Solanum americanum) Interference in Bell Pepper (Capsicum annuum)

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 526a-526
Author(s):  
Debbie L. Roos ◽  
W.M. Stall ◽  
D.G. Shilling ◽  
S.R. Kostewicz ◽  
M.E. Swisher
Keyword(s):  
Yield Loss ◽  
Crop Yields ◽  
Block Design ◽  
Critical Density ◽  
Bell Pepper ◽  
Calculated Density ◽  
Weed Interference ◽  
Black Nightshade ◽  
Solanum Americanum ◽  
American Black

Information about the effects of weed interference on crop yields can help growers make appropriate management decisions. Such information is particularly useful in horticultural crops such as pepper, where the number of registered herbicides is limited. Bell pepper is the second most-valuable vegetable crop grown in Florida, and American black nightshade (Solanum americanum) is one of the primary weeds in Florida pepper production. Additive experiments were conducted in 1997 in Florida to determine the effects of American black nightshade interference on bell pepper yield. One additive experiment was conducted in Gainesville, Fla., in the spring and two additive studies were conducted in the fall in Gainesville and Live Oak, Fla. A randomized complete-block design with four replications was used. Double rows of `Capistrano' peppers were transplanted into white polyethylene mulched beds with 1.22-m centers. Peppers were planted at an in-row spacing of 0.3 m. Weeds were propagated in the greenhouse in polystyrene flats and transplanted at the two-leaf stage simultaneously with the peppers. Overhead irrigation was used and monitored with tensiometers. Fertilizers and pesticides were applied based on Extension recommendations. Weed densities in the spring trial were 0, 2, 4, 8, 12, 16, and 20 plants/m2. Weed densities of 0, 0.5, 1, 1.5, 2, 3, 4, and 8 plants/m2 were planted in the fall. Crop and weed heights were recorded weekly, and fruit number, grade, and weights were recorded at each harvest. Crop and weed dry weights were obtained at final harvest. Data were subjected to analysis of variance and regression. There was an interaction by season, but there was not an interaction by location for the fall season; therefore, the fall data were combined. In all trials, S. americanum had a significant effect of bell pepper fruit yield. In the spring, the biological threshold of weed interference occurred at a density of four S. americanum/m2, but only caused a 50% yield loss. In the spring, the critical density causing 20% yield loss was calculated from the regression model to occur at 0.36 S. americanum/m2. A calculated density of 0.58 S. americanum/m2 caused 20% yield loss in the fall. Plant height and dry weight data indicated that the pepper initially grew more quickly in the fall than in the spring.

scholarly journals Smooth Amaranth Interference with Watermelon and Muskmelon Production

HortScience ◽  
1997 ◽  
Vol 32 (4) ◽  
pp. 630-632 ◽  
Author(s):  
Ernest R. Terry ◽  
William M. Stall ◽  
Donn G. Shilling ◽  
Thomas A. Bewick ◽  
Steven R. Kostewicz
Keyword(s):  
Cucumis Melo ◽  
Regression Models ◽  
Critical Period ◽  
Yield Loss ◽  
Total Yield ◽  
Critical Periods ◽  
Exponential Regression ◽  
Maximum Period ◽  
Best Fit ◽  
Fruit Mass

Studies were conducted to determine the critical period of smooth amaranth interference in watermelon (Citrullus lunatus L.) and muskmelon (Cucumis melo L. var. reticulatus). Best-fit linear or exponential regression models were used to predict the maximum period of competition and the minimum weed-free period for 10% yield loss. The maximum period of competition and minimum weed-free period was 0.50 and 2.97 weeks after watermelon emergence, respectively, and 1.0 and 3.9 weeks after muskmelon emergence, respectively. The critical periods of smooth amaranth interference for the crops were between those intervals. In both crops, late emerging smooth amaranth had little effect on total yield. Smooth amaranth introduced at crop emergence reduced total yield. The effect of competition on yield components, i.e., fruit number per hectare and fruit mass, varied by crop. Muskmelon fruit count was more sensitive to smooth amaranth competition than was watermelon fruit count. Conversely, mass per fruit of muskmelon was less sensitive to this competition than was mass per fruit of watermelon.

scholarly journals Selectivity of herbicide oxadiazon to processing tomato and control of American black nightshade plants

2021 ◽  
Vol 39 (1) ◽  
pp. 32-38
Author(s):  
Núbia Maria Correia
Keyword(s):  
Field Trials ◽  
Field Conditions ◽  
Control Treatment ◽  
Herbicide Application ◽  
Tomato Plants ◽  
Processing Tomato ◽  
Black Nightshade ◽  
Randomized Design ◽  
Negative Effect ◽  
American Black

ABSTRACT American black nightshade (Solanum americanum) is one of the main weeds for tomato crops. However, no herbicide approved for this crop in Brazil is effective for the control of this species and selective to tomato plants. Therefore, the objective of the present study was to evaluate the selectivity of the herbicide oxadiazon to plants of three processing tomato hybrids and the control of American black nightshade plants. Four trials were installed: one under greenhouse and three under field conditions. The greenhouse trial was conducted in a completely randomized design with four replications, using a 2x5 factorial arrangement consisting of preemergence and postemergence applications of five oxadiazon rates (75, 125, 250, 375, and 500 g ha-1) to control American black nightshade plants, and two control treatments without herbicide application. The field trials were conducted in a randomized blocks design with four replications on commercial production areas in the municipality of Cristalina-GO, Brazil. The tomato hybrids tested were Acangata 9992, H-9553, and HMX 7885, one in each trial. The treatments consisted of application of five oxadiazon rates (125, 250, 375, 500, and 625 g ha-1) at pre-planting of the tomato seedlings, and a control treatment without herbicide application. The application of oxadiazon in preemergence, in the greenhouse, was more efficient for controlling American black nightshade plants under greenhouse conditions than the application on plants with 2-3 leaves. However, the weed control was satisfactory (>90%) when rates up to 246 g ha-1 were used, in both application times. The herbicide application caused no visual injuries to tomato plants under field conditions, and had no negative effect on fruit yield. Therefore, the herbicide oxadiazon was highly selective to the three processing tomato hybrids when applied at pre-planting, using rates of up to 625 g ha-1. The herbicide presented excellent control of American black nightshade plants, using rates from 125 to 371 g ha-1.

scholarly journals Critical Period of Weed Control in Aerobic Rice

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
M. P. Anwar ◽  
A. S. Juraimi ◽  
B. Samedani ◽  
A. Puteh ◽  
A. Man
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Critical Period ◽  
Yield Loss ◽  
Field Trials ◽  
Integrated Weed Management ◽  
Aerobic Rice ◽  
View Point ◽  
Weed Interference ◽  
Economic View

Critical period of weed control is the foundation of integrated weed management and, hence, can be considered the first step to design weed control strategy. To determine critical period of weed control of aerobic rice, field trials were conducted during 2010/2011 at Universiti Putra Malaysia. A quantitative series of treatments comprising two components, (a) increasing duration of weed interference and (b) increasing length of weed-free period, were imposed. Critical period was determined through Logistic and Gompertz equations. Critical period varied between seasons; in main season, it started earlier and lasted longer, as compared to off-season. The onset of the critical period was found relatively stable between seasons, while the end was more variable. Critical period was determined as 7–49 days after seeding in off-season and 7–53 days in main season to achieve 95% of weed-free yield, and 23–40 days in off-season and 21–43 days in main season to achieve 90% of weed-free yield. Since 5% yield loss level is not practical from economic view point, a 10% yield loss may be considered excellent from economic view point. Therefore, aerobic rice should be kept weed-free during 21–43 days for better yield and higher economic return.

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.

scholarly journals Modeling the Competitive Effect of Euphorbia dracunculoides and Astragalus sp. in Zero Input Rainfed Chickpea

2018 ◽  
Vol 36 (0) ◽  
Author(s):  
R.M. IKRAM ◽  
A. TANVEER ◽  
R. MAQBOOL ◽  
M.A. NADEEN
Keyword(s):  
Protein Content ◽  
Critical Period ◽  
Field Experiments ◽  
Seed Protein ◽  
Yield Loss ◽  
Seed Protein Content ◽  
Yield Losses ◽  
Competition Period ◽  
Crop Competition ◽  
Weed Removal

ABSTRACT: Brown chickpea (Cicer arietinum L.) is one of the two chickpea types grown in Pakistan and other countries. The critical period for weed removal in a rainfed chickpea system is an important consideration in devising weed management strategies. Field experiments were conducted in the winter season of 2011 and 2012 to determine the extent of yield loss with different periods of weed crop competition. Seven weed crop competition periods (0, 45, 60, 75, 90, 105 and 160 days after sowing - DAS) were used to identify the critical period for weed removal in rainfed chickpea. Experimental plots were naturally infested with Euphorbia dracunculoides and Astragalus sp. in both years. Individual, composite density and dry weights of E. dracunculoides and Astragalussp. increased significantly with an increase in the competition period. However, yield and yield-contributing traits of chickpea significantly decreased with an increase in the competition period. Chickpea seed yield loss was 11-53% in different weed crop competition periods. Euphorbia dracunculoides and Astragalus sp. removed 39.9 and 36.9 kg ha-1 of N, 9.61 and 7.27 kg ha-1 of P and 38.3 and 36.9 kg ha-1 of K, respectively. Season long weed competition (160 days after sowing) resulted in 19.5% seed protein content compared with 24.5% seed protein content in weed-free chickpea. A Logistic equation was fitted to yield data in response to increasing periods of weed crop competition. The critical timing of weed removal at 5 and 10% acceptable yield losses were 26 and 39 DAS, respectively. The observed critical period suggests that in rainfed chickpea, a carefully timed weed removal could prevent grain yield losses.

Evaluation of Harvest-Aid Herbicides as Desiccants in Lentil Production

2016 ◽  
Vol 30 (3) ◽  
pp. 629-638 ◽  
Author(s):  
Ti Zhang ◽  
Eric N. Johnson ◽  
Christian J. Willenborg
Keyword(s):  
Adverse Effects ◽  
Crop Yield ◽  
Seed Yield ◽  
Yield Loss ◽  
Field Trials ◽  
Growth Stages ◽  
Yield And Quality ◽  
Seed Field ◽  
Dry Down ◽  
General Reduction

Desiccants are currently used to improve lentil dry-down prior to harvest. Applying desiccants at growth stages prior to maturity may result in reduced crop yield and quality, and leave unacceptable herbicide residues in seeds. There is little information on whether various herbicides applied alone or as a tank-mix with glyphosate have an effect on glyphosate residues in harvested seed. Field trials were conducted at Saskatoon and Scott, Saskatchewan, Canada, from 2012 to 2014 to determine whether additional desiccants applied alone or tank mixed with glyphosate improve crop desiccation and reduce the potential for unacceptable glyphosate residue in seed. Glufosinate and diquat tank mixed with glyphosate were the most consistent desiccants, providing optimal crop dry-down and a general reduction in glyphosate seed residues without adverse effects on seed yield and weight. Saflufenacil provided good crop desiccation without yield loss, but failed to reduce glyphosate seed residues consistently. Pyraflufen-ethyl and flumioxazin applied alone or tank mixed with glyphosate were found to be inferior options for growers as they exhibited slow and incomplete crop desiccation, and did not decrease glyphosate seed residues. Based on results from this study, growers should apply glufosinate or diquat with preharvest glyphosate to maximize crop and weed desiccation, and minimize glyphosate seed residues.

scholarly journals Improving a pest management tool for scenario analysis of economic populations of Globodera pallida

Nematology ◽  
2021 ◽  
pp. 1-11
Author(s):  
Ann-Kristin Koehler ◽  
Christopher A. Bell ◽  
Matthew A. Back ◽  
Peter E. Urwin ◽  
Howard J. Atkinson
Keyword(s):  
Scenario Analysis ◽  
Yield Loss ◽  
Meta Analysis ◽  
Field Trials ◽  
Globodera Pallida ◽  
Management Tool ◽  
Analysis Tool ◽  
The Individual ◽  
The Uk ◽  
Annual Decline

Summary Globodera pallida is the most damaging pest of potato in the UK. This work underpins enhancement of a well-established, web-based scenario analysis tool for its management by recommending additions and modifications of its required inputs and a change in the basis of yield loss estimates. The required annual decline rate of the dormant egg population is determined at the individual field sample level to help define the required rotation length by comparing the viable egg content of recovered cysts to that of newly formed cysts for the same projected area. The mean annual decline was 20.4 ± 1.4% but ranged from 4.0 to 39.7% annum−1 at the field level. Further changes were based on meta-analysis of previous field trials. Spring rainfall in the region where a field is located and cultivar tolerance influence yield loss. Tolerance has proved difficult to define for many UK potato cultivars in field trials but uncertainty can be avoided without detriment by replacing it with determinacy integers. They are already determined to support optimisation of nitrogen application rates. Multiple linear regression estimates that loss caused by pre-plant populations of up to 20 viable eggs (g soil)−1 varies from ca 0.2 to 2.0% (viable egg)−1 (g soil)−1 depending on cultivar determinacy and spring rainfall. Reliability of the outcomes from scenario analysis requires validation in field trials with population densities over which planting is advisable.

scholarly journals Effect of mancozeb on the control of mycosphaerella blight of field pea

2000 ◽  
Vol 80 (2) ◽  
pp. 403-406 ◽  
Author(s):  
T. D. Warkentin ◽  
A. G. Xue ◽  
D. W. McAndrew
Keyword(s):  
Yield Loss ◽  
Foliar Application ◽  
Genetic Resistance ◽  
Similar Efficacy ◽  
Field Trials ◽  
Field Pea ◽  
Mycosphaerella Pinodes ◽  
Western Canada ◽  
Flowering Stage ◽  
Plot Design

Mycosphaerella blight (MB) [Mycosphaerella pinodes (Berk. & Blox.)Vestergr.] causes substantial yield loss to field pea in western Canada in most seasons and is a disease for which genetic resistance is lacking. The objective of this research was to evaluate the effectiveness of foliar application of mancozeb for the control of MB of field pea. Field trials of split-plot design were conducted at two sites per year from 1996 to 1998 in southern Manitoba, with cultivars as main-plots and fungicide treatments as sub-plots. In most site-years, a single application of mancozeb at the early flowering stage was effective in reducing MB severity and in increasing yield. Mancozeb had similar efficacy to chlorothalonil, the only currently registered fungicide for control of MB in field pea. The beneficial effect of both fungicides was greater for the highly MB susceptible cultivars AC Tamor and Carrera than the moderately MB susceptible cultivar Radley. Key words: Pisum sativum, field pea, mycosphaerella blight, mancozeb, chlorothalonil

Sign in / Sign up

Export Citation Format

Share Document