EFFECT OF SEVERAL HERBICIDES ON GERMINATION, SURVIVAL, AND EARLY GROWTH OF CARAGANA AND ON WEEDS

1965 ◽  
Vol 45 (5) ◽  
pp. 477-486
Author(s):  
R. Grover

Several pre-emergence herbicides were tested, both in the greenhouse and in the field, for tolerance to germinating and 1-year-old seedlings of caragana (Caragana arborescens Lam.) and for effectiveness in controlling weeds.Dinoseb (4,6-dinitro-o-sec-butylphenol) and its alkanolamine salt at 8 lb/ac, trifluralin (alpha, alpha, alpha-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) at 4 to 6 lb/ac, DCPA (dimethyl 2,3,5,6-tetrachloroterephthalate) at 15 lb/ac, swep (methyl 3,4-dichlorocarbanilate) at 6 to 9 lb/ac, and Tenoran (N-4-(p-chlorophenoxy)-phenyl-1,1-dimethylurea) at 6 lb/ac gave satisfactory weed control with no injury to germinating caragana seedlings. Liquid formulations of dinoseb or dinoseb-amine were more effective than the granular dinoseb formulation at rates of 8 lb/ac or less. Mixtures of dinoseb, trifluralin, and DCPA were also effective and these may be used where a wider weed species spectrum is encountered.Trifluralin at 6 lb/ac and mixtures of granular dinoseb at 8 to 12 lb/ac with DCPA at 10 lb/ac also provided satisfactory weed control with no injury to 1-year-old caragana seedlings.In the greenhouse tests, pre-emergence applications of trifluralin, diphenamid (N,N-dimethyl-2,2-diphenylacetamide), swep, DCPA, and DMPA (Q-(2,4-dichlorophenyl) O-methyl isopropylphosphoramidothioate) did not retard the germination of weed seeds, but the young weed seedlings were either killed or retarded in growth as the experiments progressed. On the other hand, linuron (3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea), dichlobenil (2,6-dichlorobenzonitrile), and dinoseb affected the emergence of weed seedlings. The weeds surviving the dinoseb treatment grew well. Hand-weeding stimulated the germination of more weed seeds.

2007 ◽  
Vol 25 (3) ◽  
pp. 433-441 ◽  
Author(s):  
J.K.O. Gomes ◽  
P.S.L. Silva ◽  
K.M.B. Silva ◽  
F.F. Rodrigues Filho ◽  
V.G. Santos

Intercropping combined with competitive maize cultivars can reduce the use of herbicides to control weeds. The objective of this work was to evaluate the effects of intercropping cowpea and maize, as well as hand-weeding on maize morphology and yield. The experimental design was in randomized complete blocks, with treatments arranged in split-plots and five replications. The plots consisted of four maize cultivars (BA 8512, BA 9012, EX 4001, EX 6004) and the split-plots consisted of the following treatments: no-weeding; twice hand-weeding (20 and 40 days after sowing); and intercropping with cowpea ('Sempre Verde' cultivar), both maize and cowpea sown at the same time. The variables evaluated were: maize fresh green ears and grain yield; characteristics of internodes, leaves, tassels, ears, grains; plant height and ear insertion height; number of weed plants and species; fresh and dry biomass of weed species and cowpea. Ten weed species were outstanding during the experiment, many of them from the Poaceae family. No interactions were found between weed control method and maize cultivars for most variables evaluated; and plants from hand-weeded split-plots showed superior mean values compared to plants from non-weeded and intercropped split-plots, both not differing from each other. The cowpea was inefficient in controlling weed, reducing the maize yields and not producing any grain. The maize cultivars 'BA 8512' and 'BA 9012 showed the highest mean green ear yield, and the highest grain yield in hand-weeded, no-weeded and intercropped split-plots. On the other hand, the maize cultivar 'EX 6004' showed such high means only in no-weeded and intercropped split-plots. 'EX 4001 presented the worst means in these variables for hand-weeded, no-weeded ant intercropped split-plots.


2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Sharif Ahmed ◽  
Bhagirath Singh Chauhan

A field study was conducted in the boro season of 2011-12 and aman season of 2012 at Jessore, Bangladesh, to evaluate the performance of sequential applications of preemergence herbicides (oxadiargyl 80 g ai ha−1, pendimethalin 850 g ai ha−1, acetachlor + bensulfuranmethyl 240 g ai ha−1, and pyrazosulfuron 15 g ai ha−1) followed by a postemergence herbicide (ethoxysulfuron 18 g ai ha−1) in dry-seeded rice. All evaluated herbicides reduced weed density and biomass by a significant amount. Among herbicides, pendimethalin, oxadiargyl, and acetachlor + bensulfuranmethyl performed very well against grasses; pyrazosulfuron, on the other hand, was not effective. The best herbicide for broadleaf weed control was oxadiargyl (65–85% control); pendimethalin and acetachlor + bensulfuraonmethyl were not effective for this purpose. The best combination for weed control was oxadiargyl followed by ethoxysulfuron in the boro season and oxadiargyl followed by a one-time hand weeding in the aman season. Compared with the partial weedy plots (hand weeded once), oxadiargyl followed by ethoxysulfuron (4.13 t ha−1) provided a 62% higher yield in the boro season while oxadiargyl followed by a one-time hand weeding (4.08 t ha−1) provided a 37% higher yield in the aman season.


Weed Science ◽  
1993 ◽  
Vol 41 (3) ◽  
pp. 347-352 ◽  
Author(s):  
Glenn R. Wehtje ◽  
John W. Wilcut ◽  
John A. Mcguire

Mixtures of chlorimuron and 2,4-DB were additive with respect to crop injury and were either additive or slightly antagonistic with respect to weed control in greenhouse experiments. Absorption and translocation of14C following application of14C-chlorimuron and14C-2,4-DB were not affected by the presence of the other unlabeled herbicide, except in Florida beggarweed and peanut where 2,4-DB affected distribution of14C-chlorimuron in the treated leaf. In field studies, maximum efficacy was obtained with mixtures of chlorimuron plus 2,4-DB applied 7 or 9 wk after planting. Florida beggarweed control was greatest with chlorimuron or chlorimuron mixtures while the addition of 2,4-DB to chlorimuron improved morningglory and sicklepod control. At 9 and 11 wk after planting, addition of 2,4-DB to chlorimuron controlled Florida beggarweed better than chlorimuron alone. Peanut yields were increased by the addition of 2,4-DB at later applications.


2017 ◽  
Vol 27 (2) ◽  
pp. 199-211 ◽  
Author(s):  
S. Christopher Marble ◽  
Andrew K. Koeser ◽  
Gitta Hasing ◽  
Drew McClean ◽  
Annette Chandler

Organic mulch is commonly used in landscape planting beds to improve plant growth and reduce competition from weed species. Although many different mulch materials have been evaluated in landscape, forestry, or agricultural settings, there have been no previous reports concerning the maintenance costs associated with different mulch materials from a weed control perspective. Trials were conducted at two locations in Florida to estimate the annual maintenance costs associated with pine bark nuggets (bark derived from pine species not specified) and pine straw mulch [mix of longleaf pine (Pinus palustris) and slash pine (Pinus taeda) needles] with and without the use of a granular preemergence herbicide when maintained at similar depths in schilling’s holly (Ilex vomitoria ‘Schilling’s Dwarf’) shrub beds and asiatic jasmine (Trachelospermum asiaticum ‘Minima’) groundcover beds. Weed coverage and residual mulch depth were tracked over time, with maximum and minimum thresholds (20% and 2 inches, respectively) set as triggers for maintenance activities. Results showed that the addition of herbicide (trifluralin + isoxaben) had little to no impact on weeding frequency or time when plots were mulched, but did reduce hand weeding frequency and time compared with nontreated, nonmulched plots. Both mulch materials used alone reduced hand weeding frequency and time compared with herbicide-only treatments. Although results varied by bed type and location, pine bark generally provided greater weed control compared with pine straw and required fewer mulch additions and less mulch by volume. Results from this study suggests that using pine bark nuggets as mulch may result in lower maintenance costs and weed pressure compared with pine straw when both are applied and maintained at 2-inch depths.


1967 ◽  
Vol 47 (5) ◽  
pp. 593-596
Author(s):  
E. S. Molberg

Injury to flax was greater from root uptake than from foliage absorption of dicamba (2,3-dichloro-o-anisic acid) in greenhouse tests. Applications of 0.140 kg/ha (2 oz/acre) of dicamba to both foliage and soil in an overall spray, combined with leaching of the chemical to the root zone, injured the flax beyond recovery. On the other hand, an overall spray without subsequent leaching caused negligible injury. The data help explain the occasional severe injury to flax experienced in field operations.


2020 ◽  
Author(s):  
Akashdeep Singh ◽  
S. S. Rana ◽  
Anju Bala

Chickpea (Cicer arietinum) is one of the most important pulse crops but it’s productivity in India is quite low. There are various reasons for low productivity. Weed control is the basic requirement and the major component of crop management. Weeds on an average reduce the crop yield by 40-87 per cent. Deciding time to control weeds requires detailed knowledge of the weed populations in the field. Different management practices like altering spacing, competitive cultivars, etc. can help in enhancing the productivity. With the world entering the precision-farming era, more emphasis is being put on the use of post-emergence herbicides. Application of two or more herbicide at the same time or as a double knockdown and integrating with hand-weeding provides desirable control of different weed species besides reducing the hazard of chemical weed control.


1980 ◽  
Vol 60 (3) ◽  
pp. 917-922 ◽  
Author(s):  
J. A. IVANY

The effects of different periods of weed competition and of trifluralin (α,α,α-trifluro-2,6-dinitro-N,N-dipropyl-p-toluidine), niclofen (2,4-dichloro-phenyl-p-nitrophenyl ether), and cultivations were studied for effects on yield of rutabaga (Brassica napobrassica Mill. ’York’). Delaying weed removal for 4 wk after crop emergence significantly reduced yields of marketable and total roots compared with plots kept weed-free all season. Delayed weeding beyond 4 wk resulted in progressively greater reductions in yield. Rutabagas kept weed-free for 2, 4, 6, and 8 wk from crop emergence by once-weekly weeding gave yields comparable to those kept weed-free all season. Herbicide treatments without hand-weeding gave significantly lower yields than those with one hand-weeding. The use of three hand-weedings with herbicides was not significantly better than herbicides with one hand-weeding. Level of weed control was dependent on weed species present in the test area; however, a combination of trifluralin and niclofen gave a broader spectrum of control and better crop yields than either used alone.


2015 ◽  
Vol 29 (1) ◽  
pp. 56-62 ◽  
Author(s):  
Hassan Karimmojeni ◽  
Ali Reza Yousefi ◽  
Per Kudsk ◽  
Amir Hossein Bazrafshan

Winter sowing of lentil results in higher yields than a spring-sown crop. However, when lentil is winter-sown, the critical period of weed control is extended and might require sequential herbicide management strategies to obtain maximum yields. The efficacy of POST alone or soil applied followed by (fb) POST herbicides or hand weeding were evaluated in 2002 and 2003. Trifluralin (PPI) or pendimethalin (PRE) were applied at planting, and pyridate or oxyfluorfen were applied POST at the three- to four-leaf stage of lentil. The lowest level of weed biomass was recorded with all treatments, except pyridate alone in both years, pendimethalin PRE fb pyridate in 2002, and oxyfluorfen in 2003. Application of pyridate or oxyfluorfen POST alone resulted in lower yields. In 2002, trifluralin PPI or pendimethalin PRE fb one hand weeding or pendimethalin fb pyridate resulted in yields similar to the weed-free treatment. In 2003, yields were similar to the weed-free treatment, except pyridate or oxyfluorfen alone and trifluralin PPI fb oxyfluorfen. Weed species observed in the present study required sequential management to achieve both effective control and maximum lentil yield.


2013 ◽  
Vol 27 (3) ◽  
pp. 431-436 ◽  
Author(s):  
Michael Walsh ◽  
Peter Newman ◽  
Stephen Powles

The widespread evolution of multiple herbicide resistance in the most serious annual weeds infesting Australian cropping fields has forced the development of alternative, non-chemical weed control strategies, especially new techniques at grain harvest. Harvest weed seed control (HWSC) systems target weed seed during commercial grain harvest operations and act to minimize fresh seed inputs to the seedbank. These systems exploit two key biological weaknesses of targeted annual weed species: seed retention at maturity and a short-lived seedbank. HWSC systems, including chaff carts, narrow windrow burning, bale direct, and the Harrington Seed Destructor, target the weed seed bearing chaff material during commercial grain harvest. The destruction of these weed seeds at or after grain harvest facilitates weed seedbank decline, and when combined with conventional herbicide use, can drive weed populations to very low levels. Very low weed populations are key to sustainability of weed control practices. Here we introduce HWSC as a new paradigm for global agriculture and discuss how these techniques have aided Australian grain cropping and their potential utility in global agriculture.


2006 ◽  
Vol 12 (2) ◽  
pp. 161 ◽  
Author(s):  
Valentín A. Esqueda ◽  
Liviana Altamirano ◽  
Yanett Hernández ◽  
Alicia López

An experiment was established at Rancho Casablanca, located in the Municipality of Puente Nacional, in the State of Veracruz, Mexico, in order to evaluate the toxicity caused by the mixture of the herbicides ametryn + clomazone to the sugarcane varieties MEX-79-431, MEX- 69-290, MEX-68-P23 and CP-72-2086. Four weed control treatments were evaluated: 1. Ametryn + clomazone (1200 + 800 g/ha), 2. Ametryn + clomazone (1800 + 1200 g/ha), 3. Ametryn + 2,4-D (1225 + 650 g/ha) and 4. Weeded control. Herbicides were applied when sugarcane plants had from two to four leaves. The mixture of ametryn + clomazone caused leaf bleaching in all the sugarcane varieties. The bleached area varied from 36.3 to 47.5% with the highest dose of the mixture, and from 25 to 39.4%, with the lowest dose, and it practically disappeared about 45 days after application. On the other hand, the mixture of ametryn + 2,4-D did not cause any bleaching. Toxicity caused by the mixture of ametryn + clomazone did not affect the number of plant leaves, the number of stalks in 2 linear m, nor the plant height. Stalk yield and sucrose content were not affected either.


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