scholarly journals Herbicide Selectivity in Peanut Cultivars

2018 ◽  
Vol 10 (8) ◽  
pp. 447
Author(s):  
Henrique Gonzalez Zanardo ◽  
Willians César Carrega ◽  
Neriane Hijano ◽  
Anne Elise Cesarin ◽  
Pedro de F. R. Barbosa Martins ◽  
...  
Keyword(s):  
Weed Control ◽  
Dry Mass ◽  
Field Conditions ◽  
Yield Potential ◽  
Control Methods ◽  
Weed Interference ◽  
Peanut Crop ◽  
Main Factors ◽  
Peanut Cultivars

Weed interference is one of the main factors responsible for reducing the productivity of the peanut crop. Among weed control methods, the chemical is considered one of the main tools, however, the herbicides registered for this crop are scarce. The objective of this study was to evaluate the selectivity of herbicides applied in post-emergence in Runner peanut cultivars. For this, an experiment was performed in an 11x5 factorial scheme, meaning 10 herbicides plus one control (without herbicide) and five peanut cultivars, with four replicates. Visual evaluations of phytointoxication were carried out at 7, 14 and 21 days after application of the herbicides. At the end of the experiment, was determined the dry mass of aboveground and root parts. Based on the results obtained, it is concluded that the herbicides 2,4-D (1.50 L ha-1), mesotrione (0.3 L ha-1), saflufenacil (0.75 L ha-1), imazapic (175 g ha-1) and S-metolachlor (1.75 L ha-1) have potential to be used for all the peanut cultivars studied. Herbicides hexazinone (2.50 kg ha-1), amicarbazone (2.00 kg ha-1), tebuthiuron (2.00 L ha-1), clomazone (2.00 L ha-1) and sulfentrazone (1.20 L ha-1) must not be indicated, at these doses, for post-emergence spraying in the evaluated cultivars. The genotypes do not react equally to certain products, therefore, there is a need for further studies the at field conditions to attest the responses obtained in the present study and verify that the yield potential is not affected.

scholarly journals WEED COMMUNITY INTERFERENCE AND PHYTOSOCIOLOGICAL STUDIES IN A SWEET SORGHUM CROP

2017 ◽  
Vol 35 (0) ◽  
Author(s):  
P.R.F. GIANCOTTI ◽  
M.S. MORO ◽  
M.P. NEPOMUCENO ◽  
P.F.R.B. MARTINS ◽  
A.A.M. BARROSO ◽  
...  
Keyword(s):  
Weed Control ◽  
Sweet Sorghum ◽  
Biomass Accumulation ◽  
Dry Mass ◽  
Summer Season ◽  
Cyperus Rotundus ◽  
Fall Season ◽  
Weed Population ◽  
Weed Interference ◽  
Indigofera Hirsuta

ABSTRACT This research was carried out to evaluate the interference periods and phytosociological indexes of the weed community on sweet sorghum, hybrid CVSW 80007, cultivated for two seasons in a year. The treatments were based on an increased duration of weed presence and weed absence after sowing (0, 4, 7, 14, 21, 28, 35, 42, 56 and 68 days after crop emergence for the summer season and 0, 4, 7, 14, 21, 28, 35, 42, 49, 56, 63 and 100 days for the fall season). The weed community was evaluated based on the number of weeds and the dry mass of each weed population in each period of weed control in the summer season and each period of no weed control and weed control in the autumn season. These data were used to determine the relative indexes of density, dominance and importance, and the weed community indexes of diversity and equitability. The main weeds comprising the community were Cyperus rotundus, Alternanthera tenella, Indigofera hirsuta, Amaranthus sp., Digitaria nuda, and Portulaca oleracea. The weed density was found to be the primary factor for the importance of weeds in the community, once their development and biomass accumulation were suppressed by the sweet sorghum competition. The sweet sorghum hybrid proved highly competitive and, in the agro-ecological conditions of the trials, weed interference did not reduce crop yield.

scholarly journals Impact of the timing and duration of weed control on the establishment of a rubber tree plantation

2014 ◽  
Vol 86 (1) ◽  
pp. 495-504
Author(s):  
CAIO D. GUZZO ◽  
LEONARDO B. DE CARVALHO ◽  
PAULO R.F. GIANCOTTI ◽  
PEDRO L.C.A. ALVES ◽  
ELAINE C.P. GONÇALVES ◽  
...  
Keyword(s):  
Plant Height ◽  
Weed Control ◽  
Critical Period ◽  
Rubber Tree ◽  
Dry Mass ◽  
First Year ◽  
Tree Plantation ◽  
Weed Interference ◽  
Growth Recovery ◽  
Second Year

Rubber tree production is reduced by weeds that compete for environmental resources; therefore, the timing and duration of weed control influences weed interference. The objectives of this study were to evaluate the growth of rubber tree (Hevea brasiliensis) plants, to determine the critical period for weed control, and to evaluate the growth recovery of rubber trees that coexisted with weeds for different periods of time after planting. Two groups of treatments were established under field conditions in the first year of the investigation: one group contained crescent periods of weed infestation, while the other contained crescent periods of weed control, also including a weed-free check and a total weedy check. In the second year of the investigation, the weeds were totally controlled. Urochloa decumbens was the dominant weed (over 90% groundcover). Crop growth was greatly reduced due to the weed interference. Plant height decreased more rapidly than did any other characteristic. Plant height, leaf dry mass, and leaf area decreased by 99%, 97% and 96%, respectively, and were the most reduced characteristics. Plant height also recovered more rapidly than did any characteristic when the period of weed control was lengthened. However, stem dry mass increased by 750%, making it the most recovered characteristic. The critical period for weed control was between 4 and 9½ months after planting in the first year; however, the rubber trees showed an expressive growth recovery when the weeds were controlled throughout the second year.

Why Early Season Weed Control Is Important in Maize

Weed Science ◽  
2012 ◽  
Vol 60 (3) ◽  
pp. 423-430 ◽  
Author(s):  
Eric R. Page ◽  
Diego Cerrudo ◽  
Philip Westra ◽  
Mark Loux ◽  
Kenneth Smith ◽  
...  
Keyword(s):  
Grain Yield ◽  
Weed Control ◽  
Dry Matter ◽  
Yield Loss ◽  
Treatment Plant ◽  
Field Trials ◽  
Yield Potential ◽  
Dry Matter Accumulation ◽  
State University ◽  
Weed Interference

Control of early-emerging weeds is essential to protect the yield potential of maize. An understanding of the physiological changes that occur as a result of weed interference is required to address variability in yield loss across sites and years. Field trials were conducted at the University of Guelph (UG), the Ohio State University (OSU), and Colorado State University (CSU) during 2009 and 2010. There were six treatments (season-long weedy and weed-free, and weed control at the 1st-, 3rd-, 5th-, and 10th-leaf-tip stages of maize development) and 20 individual plants per plot were harvested at maturity. We hypothesized that, as weed control was delayed, weed interference in the early stages of maize development would increase plant-to-plant variability in plant dry-matter accumulation, which would result in a reduction of grain yield at maturity. The onset of the critical period for weed control (CPWC) occurred on average between the third and fifth leaf tip stages of development (i.e., V1 to V3, respectively). Rate of yield loss following the onset of the CPWC ranged from 0.05 MG ha−1d−1at UG 2009 to 0.22 MG ha−1d−1at CSU 2010 (i.e., 0.5 and 1.6% d−1, respectively). On average, reductions in kernel number per plant accounted for approximately 65% of the decline in grain yield as weed control was delayed. Biomass partitioning to the grain was stable through early weed removal treatments, increased and peaked at the 10th-leaf-tip time of control, and decreased in the season-long weedy treatment. Plant-to-plant variability in dry matter at maturity and incidence of bareness increased as weed control was delayed. As weed control was delayed, the contribution of plant-to-plant variability at maturity to the overall yield loss was small, relative to the decline of mean plant dry matter.

scholarly journals SENSITIVITY OF SWEET POTATO GENOTYPES TO CLOMAZONE AND WEED INTERFERENCE

2018 ◽  
Vol 31 (2) ◽  
pp. 352-359 ◽  
Author(s):  
EDSON APARECIDO DOS SANTOS ◽  
VALTER CARVALHO DE ANDRADE JÚNIOR ◽  
DANIEL JOSÉ SILVA VIANA ◽  
ALBERTIR APARECIDO DOS SANTOS ◽  
ANTÔNIO JULIO MEDINA DA SILVA ◽  
...  
Keyword(s):  
Experimental Design ◽  
Weed Control ◽  
Sweet Potato ◽  
Branch Length ◽  
Growth And Yield ◽  
Control Methods ◽  
Root Yield ◽  
Weed Interference ◽  
Four Blocks ◽  
Mechanical Weed Control

ABSTRACT Sweet potato is a promising crop in Brazil due to its potential for bioenergy production. However, little information on adequate chemical weed control is found for this crop. Thus, the objective of this work was to evaluate the effect of clomazone on 20 genotypes of sweet potato and the sensitivity of these materials to weed interference. A field experiment was conducted using an experimental design with four blocks arranged in split-plots. The sweet potato genotypes Brazlândia-Branca, Cariru-Vermelha, Princesa, Tomba-Carro-1 and UFVJM (01, 05, 06, 07, 08, 10, 14, 23, 26, 30, 35, 42, 43, 46, 48 and 49) were grown for 180 days under three weed managements (soils treated with clomazone, mechanically weeded and with no weed control). The plots consisted of the weed control methods and the subplots consisted of the sweet potato genotypes. Phytotoxicity, branch growth and yield were evaluated. Plants grown with no weed interference had larger branch length. The highest yields were found in clomazone-treated soils. Weed interference reduced 81 to 99.7% of the yield. The less susceptible genotypes to weed interference were UFVJM07, UFVJM10 and UFVJM35, and the most sensitive were Princesa and UFVJM01. The root yield of plants under chemical weed control was similar to or greater than those with mechanical weed control in 17 of the 20 genotypes evaluated.

scholarly journals Herbicide selectivity and weed control in cowpea

2019 ◽  
Vol 13 ◽  
pp. 101
Author(s):  
José Roberto Antoniol Fontes ◽  
Inocencio Junior Oliveira ◽  
Ronaldo Ribeiro Morais
Keyword(s):  
Weed Control ◽  
Yield Loss ◽  
The Other ◽  
Field Conditions ◽  
Effectiveness Evaluation ◽  
Control Effectiveness ◽  
Weed Interference ◽  
Crop Cycle ◽  
Delayed Development

Weeds negatively affect cowpea plants, causing reduced growth, delayed development and yield loss. The aim of this study was to assay selectivity and effectiveness of weed control herbicides in cowpea cropping field conditions. For selectivity evaluation, the herbicide S-metolachlor, was used pre-emergence (PRE), and carfentrazone-ethyl, clethodim, fenoxaprop-p-ethyl, fluazifop-p-butyl and quizalofop-p-ethyl post-emergence (POST). In effectiveness evaluation, S-metolachlor (PRE), and carfentrazone-ethyl (POST), S-metolachlor in PRE and fluazifop-p-butyl (POST), clethodim, carfentrazone-ethyl and clethodim, fenoxapropp- ethyl, carfentrazone-ethyl and fenoxaprop-p-ethyl, fluazifop-p-butyl, carfentrazone-ethyl and fluazifop-pbutyl, quizalofop-p-ethyl and carfentrazone-ethyl and quizalofop-p-ethyl (POST). Two controls were included, one with weeding at 15 and 35 days after sowing (DAS) and the other without weed control. Carfentrazone-ethyl caused mild phytotoxicity in plants seven days after application, but did not reduce yield (2337 kg ha-1). The levels of weed control and productivity obtained with S-metolachlor alone or in association with carfentrazoneethyl or fluazifop-p-butyl, associated or not with carfentrazone-ethyl, were similar to those obtained with weeds. Spraying with carfentrazone-ethyl alone resulted in low control effectiveness and reduced yield (1511 kg ha-1). Weed interference during the crop cycle reduced yield by 77% (531 kg ha-1). The selectivity and effectiveness obtained with the herbicides should be considered as an agronomic and economically-viable.

Foliar Penetration and Phytotoxicity of Paraquat as Influenced by Peanut Cultivar1

1991 ◽  
Vol 18 (2) ◽  
pp. 67-71 ◽  
Author(s):  
G. Wehtje ◽  
J. W. Wilcut ◽  
J. A. McGuire ◽  
T. V. Hicks
Keyword(s):  
Arachis Hypogaea ◽  
Untreated Control ◽  
Field Studies ◽  
Yield Potential ◽  
Laboratory Studies ◽  
Foliar Absorption ◽  
Arachis Hypogaea L ◽  
Herbicide Treatments ◽  
Peanut Cultivars

Abstract Field studies were conducted over a three year period to examine the sensitivity of four peanut (Arachis hypogaea L.) cultivars (Florunner, Sunrunner, Southern runner, and NC 7) to foliar applications of paraquat (1, 1′-dimethyl-4, 4′-bipyridinium ion). Treatments included an untreated control and four herbicide treatments: paraquat applied alone at 0.14 and 0.28 kg/ha, or tank mixed with alachlor [2-chloro-N-(2, 6-diethylphenyl)-N-(methoxymethyl)acetamide] at 4.40 kg/ha. Weeds were hand-removed so that only herbicidal treatments were variables. Paraquat phytotoxicity did not differ between cultivars. No cultivar evaluated was abnormally sensitive nor tolerant to any paraquat-containing treatment. Laboratory studies utilizing radio labelled paraquat revealed that foliar absorption and translocation of paraquat did not vary between peanut cultivars. Yield differences were attributed to differences in yield potential between cultivars.

Evaluation of Imazethapyr for Weed Control in Leafy Vegetable Crops

1996 ◽  
Vol 10 (2) ◽  
pp. 253-257 ◽  
Author(s):  
Joan A. Dusky ◽  
William M. Stall
Keyword(s):  
Regression Analysis ◽  
Weed Control ◽  
Crop Yield ◽  
Relative Sensitivity ◽  
Leafy Vegetable ◽  
Field Conditions ◽  
Vegetable Crops ◽  
Weed Species ◽  
Common Lambsquarters ◽  
Common Purslane

Imazethapyr was evaluated PRE and POST in five lettuce types and chicory under Florida field conditions. The relative sensitivity of leafy crop vigor (most sensitive to most tolerant) to imazethapyr PRE, based on 20% inhibition determined using regression analysis, was as follows: Boston > bibb > crisphead > romaine > leaf > escarole > endive. Leafy crop injury increased as the rate of imazethapyr applied POST increased, with all leafy crops responding in a similar manner. Surfactant addition increased imazethapyr phytotoxicity. Imazethapyr PRE treatments at 0.067 kg ai/ha provided greater than 80% control of livid amaranth, common purslane, flatsedge, and common lambsquarters. Imazethapyr POST at 0.067 kg/ha, with surfactant provided control greater than 85% of all weed species. Greater than 85% spiny amaranth control was provided by imazethapyr POST at 0.017 kg/ha. Use of surfactant with imazethapyr did not improve spiny amaranth control over imazethapyr with no surfactant. POST treatments did not decrease leafy crop yield compared with the hand-weeded check. Imazethapyr applied PRE reduced crop yield compared to the POST treatments and the hand-weeded control.

scholarly journals Integrating Economics in the Critical Period for Weed Control Concept in Corn

Weed Science ◽  
2014 ◽  
Vol 62 (4) ◽  
pp. 608-618 ◽  
Author(s):  
Martina Keller ◽  
Geoffroy Gantoli ◽  
Jens Möhring ◽  
Christoph Gutjahr ◽  
Roland Gerhards ◽  
...  
Keyword(s):  
Weed Control ◽  
Critical Period ◽  
Logistic Models ◽  
Crop Growth ◽  
Growth Stages ◽  
Corn Yield ◽  
Leaf Stage ◽  
Weed Interference ◽  
Free Interval ◽  
Crop Growth Stages

The effect of weed interference on corn yield and the critical period for weed control (CPWC) were determined in Germany and Benin. Treatments with weed control starting at different crop growth stages and continuously kept weed-free until harvest represented the “weed-infested interval.” Treatments that were kept weed-free from sowing until different crop growth stages represented the “weed-free interval.” Michaelis–Menten, Gompertz, logistic and log–logistic models were employed to model the weed interference on yield. Cross-validation revealed that the log–logistic model fitted the weed-infested interval data equally well as the logistic and slightly better than the Gompertz model fitted the weed-free interval. For Benin, economic calculations considered yield revenue and cost increase due to mechanical weeding operations. Weeding once at the ten-leaf stage of corn resulted already profitable in three out of four cases. One additional weeding operation may optimize and assure profit. Economic calculations for Germany determined a CPWC starting earlier than the four-leaf stage, challenging the decade-long propagated CPWC for corn. Differences between Germany and Benin are probably due to the higher yields and high costs in Germany. This study provides a straightforward method to implement economic data in the determination of the CPWC for chemical and nonchemical weed control strategies.

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