Control of purple nutsedge (Cyperus rotundus) in cotton with benfuresate

The herbicide benfuresate applied preplanting to cotton (Gossypium hirsutum L.) fields infested with purple nutsedge (Cyperus rotundus L.) inhibited nutsedge growth for several weeks and was found selective for cotton. The best nutsedge control was achieved when the herbicide was mechanically incorporated following a preplant broadcast or band application which was activated by a sprinkler irrigation. The rate of benfuresate needed for effective and selective nutsedge control in cotton ranged from 0.80 to 1.60 kg/ha, the higher rates necessary in soils with higher clay and organic matter contents.     

Chemical Control of Weeds in Cotton in the Sudan Gezira

Abstract

Early work on chemical weed control in the fallow towards the end of the Second World War is reviewed briefly. Attempts to use contact residual herbicides as pre-emergence applications in the early 1950s are also described.

Pre-sowing applications of residual herbicides were found more phytotoxic to cotton than pre-emergence applications. The closer the time of pre-sowing application to cotton sowing, the more effective was suppression of weeds competing with cotton.

Mechanical cultivations and particularly disc ploughing and rotovation to a depth of more than 15 cm were found more effective in the control of Cynodon dactylon than pre-sowing herbicide applications.

Fluometuron, noruron and prometryne were found very effective as pre-emergence herbicides. Optimum rates of application were found to be only 25-50% of rates recommended for the USA and other countries. Resistant weeds included Cyperus rotundus, Cynodon dactylon, and Rhyncosia memnonia.

A large-scale trial with fluometuron, covering 125 feddans at Wad el Nairn showed that yields obtained were equal to those with normal weeding. Costs of herbicide treatments were also comparable to costs of hand-weeding in a year of exceptionally low hand-weeding costs.     

Control of johnsongrass (sorghum halepense) in cotton fields

Control of johnsongrass (Sorghum halepense (L.) Pers.) in cotton fields was achieved by the combined action of two herbicides: 1.5 kg/ha trifluralin incorporated preplanting prevented emergence of seedlings throughout the cotton growth season and reduced the vigor of rhizomes; and 1.25 kg/ha fluaziflop applied postemergence to the cotton crop selectively inhibited the growth of established rhizomes of the grass and completed the control. Reducing the spray volume for fluazifop from 300 to 200 1/ha resulted in efficient control of johnsongrass with lower rates of the herbicide.     

Interaction between timings and doses of quindorac in rice

Quinclorac (3,7-dichloro-8-quinolinecarboxylic acid) is a new herbicide in United States rice production. Field studies were conducted in 1990 and 1991 in Mississippi to determine the influence of application timings and rates on weed control efficacy and rice yield. Control of Echinochloa crus-galli (L.) Beauv. (barnyard-grass), Sesbania exaltata (Raf.) Rydb. ex A. W. Hill (hemp sesbania) and Ipomoea wrightii Gray (palmleaf morning glory) were greatest with early post-emergence application. Efficacy of pre-emergence application depends strongly on soil moisture, with significantly reduced weed control resulting when applied to dry soil. Weed control with pre-emergence application to moist soil was comparable with early post-emergence application at higher rates of quinclorac. Pre-plant and incorporated quinclorac controlled weeds effectively. Control of E. crus-galli, S. exaltata and I. wrightii ranged from 73 to 99%, 75 to 99%, and 92 to 99% at 28 days after treatment, respectively. Rice yield generally reflected weed control. No rice injury was observed for any treatment. Results indicate that early post-emergence application of quinclorac is the best time for using reduced rates and field conditions at application should be considered with these rates pre-emergence.     

Real-time weed detection, decision making and patch spraying in maize, sugarbeet, winter wheat and winter barley

Information on temporal and spatial variation in weed seedling populations within agricultural fields is very important for weed population assessment and management. Most of all, it allows a potential reduction in herbicide use, when post‐emergence herbicides are only applied to field sections with weed infestation levels higher than the economic weed threshold; a review of such work is provided. This paper presents a system for site‐specific weed control in sugarbeet (Beta vulgaris L.), maize (Zea mays L.), winter wheat (Triticum aestivum L.) and winter barley (Hordeum vulgare L.), including online weed detection using digital image analysis, computer‐based decision making and global positioning systems (GPS)‐controlled patch spraying. In a 4‐year study, herbicide use with this map‐based approach was reduced in winter cereals by 60% for herbicides against broad‐leaved weeds and 90% for grass weed herbicides. In sugarbeet and maize, average savings for grass weed herbicides were 78% in maize and 36% in sugarbeet. For herbicides against broad‐leaved weeds, 11% were saved in maize and 41% in sugarbeet.     

Efficacy of chemical weed control in spring cereals in Finland

A national survey was conducted in Finland from 1982 to 1984 to determine the main weed species in spring cereals and the efficacy of herbicides on Finnish farms. The most common dicotyledonous weeds producing the highest biomass in spring cereals were Chenopodium album L., Galeopsis spp. L., Stellaria media (L.) Vill. and Lapsana communis L. The main grass weed was Elymus repens (L.) Gould. The average reduction of weed biomass by herbicide treatment was 75%. More reliable efficacy was obtained with herbicide mixtures than with MCPA alone.     

Weed flora distribution in Greek cotton fields and its possible influence by herbicides

A weed survey methodology was used for 2 years in three provinces in Greece to determine the abundance and spatial distribution of weeds in cotton (Gossypium hirsutum L.) fields. Based on a stratified random sampling procedure, the most frequently occurring weeds were counted in 150 cotton fields. The field surveys were conducted late in the growing season; hence, the weed populations consisted of species that had been present during the critical competitive period for the crop and may have contributed to yield losses.Solanum nigrum was the most abundant weed in the surveyed fields of the southern province, followed byCyperus rotundus, Convolvulus arvensis, Xanthium strumarium, Chrozophora tinctoria andCynodon dactylon, in descending order. The ranked weed flora in the fields of the northern province was differentiated, suggesting the geographical distribution of weed species. The weedsDatura stramonium andS. nigrum were recorded in high abundance and followed byAmaranthus spp.,Abutilon theophrasti, Portulaca oleracea, Chenopodium album andXanthium spinosum, in descending order. Although the use of preplant incorporated herbicides is the dominant practice in cotton cultivation, certain weeds continue to spread in increasing densities. http://www.phytoparasitica.org posting July 26, 2005.     

EFFECTS OF HERBICIDES ON THE PRODUCTIVITY OF FODDER MAIZE WITH ESPECIAL REFERENCE TO PRE-EMERGENCE APPLICATIONS OF 2,4-D-AMINE

Summary. The effectiveness of pre-emergence applications of 2,4-D for weed control in maize was studied In five experiments, in comparison with other herbicide treatments. 2,4-D-aimne applied before crop emergence gave satisfactory weed control if the subsequent conditions were wet, but post-emerge nee applications only killed some species ( Chenopodium album and Atriplex patula. ) A combination of 2,4-D-amine, applied pre-emergence to a moist soil and subsequently as a foliar spray, controlled completely C. album, A. patula, Stellaria media and Veronica spp. Pre-emergence applications of simazine gave better weed control with less need for rain soon after application. Only A. patula was usually resistant. Pre-emergence treatments of atrazine killed all weeds whilst linuron controlled S. media, A. patula., C. album and Sonchus oleraceus but not Veronica spp.
Irrigation experiments showed that weed competition for water was largely responsible for the depressions in the early growth of maize when the conditions were dry. Final yield largely reflected the degrees of weed control attained by the herbicidal treatments. Only 2,4-D applied pre-emergence, and followed by heavy rain caused a direct depression in yield.
Effects des herbicides sur la productivityé du mals fourrage avec référence particuliére aux applications en pré-levée du 2,4-D amine     

Physiological effects of buthidazole on Zea mays L., Amaratithus retroflexus L., Medicago sativa L. and Agropyron repens(L.) Beauv.*

Buthidazole (3-[5-(1,1-dimethylethyl)-1,3.4-thiadiazol-2-yl]-4-hydroxy-l-methyl-2-imidazolidinone) at concentrations of 10^?6-10^?4M did not affect germination of corn (Zea mays L.,‘Pioneer 3780’), redroot pigweed (Amaranlhus retroflexus L.), alfalfa (Medicago saliva L., ‘Vernal’), and quackgrass (Agropyron repens(L.) Beauv.) seeds. Stressing the seeds obtained from mature corn plants treated either pre-emergence or pre- plant incorporated with buthidazole at several rates by accelerated ageing and cold treatments further indicated that this herbicide did not affect germination. Total photosynthesis and dark respiration of corn plants 12 days after pre-emergence application and of redroot pigweed, alfalfa, and quackgrass plants after postemergence application of buthidazole at several rates were measured with an infrared CO₂ analyser. The results suggested that buthidazole was a rapid inhibitor of photosynthesis of the sensitive redroot pigweed and quackgrass plants, with less effect on corn and alfalfa. Buthidazole did not affect respiration of the examined species except for a transitory increase in corn and alfalfa 12 days after pre-emergence or 4 h after postemergence treatment with buthidazole at 0.56 or 1.12 and 2.24 kg/ha, respectively. A long-term inhibition of quackgrass respiration 96 h after treatment with buthidazole at 1.12 and 224 kg/ha was also evident.     

ÉTUDE DU COMPORTEMENT DU PEBC ET DE SON UTILISATION POUR LE DÉSHERBAGE DES BETTERAVES

Summary. A series of experiments was carried out in glasshouses and in fields to study the - behaviour of PEBC and its possible use for weed control in different beet crops as compared with other herbicides. The loss by volatilization of PEBC does not seem to constitute an important factor of dissipation, when the herbicide is applied on dry soil without incorporation; the herbicidal activity was even increased after an exposure of several days on the dry soil surface. The clay and organic matter content of the soil affected the activity of PEBC. In the field trials on sugar beet, fodder beet and red beet, PEBC was sprayed on dry soil before or after planting and activated by sprinkler irrigation or rainfall after 12 or 48 hr. In the pre-planting experiment, deep incorporation by disk-harrow and shallow incorporation by roller were compared with a non-incorporated treatment; the herbicidal activity of PEBG was significantly lower with deep incorporation. In two pre-emergence experiments, incorporation by rolling was compared with non-incorporation; the control of weeds susceptible to PEBC was somewhat better when the application was followed by rolling. PEBC was active against annual grasses and fairly active against Amaranthus spp. and Portulaca oleracea, which constitute the majority of the weeds infesting beet fields in Israel. Cruciferae were quite tolerant and perennial weeds were resistant to PEBC. Sugar beet, fodder beet and red beet tolerated doses of PEBC capable of satisfactory weed control. The activity of PEBC treatment lasted for 1 or 2 months. Under the specific conditions of beet cultivation in Israel, the application of PEBC before emergence, possibly followed by rolling, appears to be a promising herbicidal treatment. Untersuchungen über die Eigenschaften von PEBC (S-propyl N-Aubuty N-äthylthiolcarbamat) und dessen Eignung zur Unkrautbekämpfung in Rüben.     

Selective control of graminaceous weeds in spring wheat

Infestation of wheat fields in Israel by graminaceous weeds is increasing due to effective control of broad-leaf weeds and lack of crop rotation. The main graminaceous weeds are wild oat (Avena sterilis L.) and wild canarygrass (Phalaris paradoxa L. andPh. brachystachys L.). In eight experiments carried out in wheat fields during 1975–1977, wild oat was effectively controlled by post-emergence applications of barban, isoproturon and difenzoquat, while wild canarygrass was controlled by post-emergence applications of barban, isoproturon and metha-benzthiazuron.     

Soybean weed control by chloramben granules coated with haloxyfop-methyl

Experimental granules were made from moistened calcareous loess (pH 8·5) containing 2% w/w gum xanthan and chloramben sodium salt at w/w concentrations of 0·4–3·6%. Haloxyfopmethyl * * Approved WSSA common name.
(DOWCO-453 ME) {Methyl 2-(4-((3-chloro-5-(trifluoromethyl)-2-pyridinyl)oxy)-phenoxy)propanoate) was dissolved in tung oil at a range of concentrations and poured on the dried chloramben granules with stirring. In the glasshouse, dry granules containing chloramben plus haloxyfop-methyl spread pre-emergence at the rate of 0·8 + 0·4 kg ha^?1 reduced the dry weight of maize (Zea mays L.), red rice (Oryza sativa L.), Abutilon theophrasti Medic., and Sesbania exaltata (Raf.) Cory by 89, 100, 94, and 68%, respectively, with no injury to soybeans [Glycine max (L.) Merr.]. Coated granules spread pre-emergence controlled A. theophrasti and volunteer maize grown from seed sown in soil up to 10 cm deep. In a preliminary field test, the experimental granules reduced numbers of weeds in soybeans and improved crop yield. Ten weeks after treatment, chloramben granules coated with haloxyfop-methyl gave 97% control of Sorghum halepense (L.) Pers compared to 80% by uncoated granules. Linuron granules coated with haloxyfop-methyl gave 85% control compared to 12% by uncoated granules. Yields in plots treated with coated and uncoated chloramben were 3280 and 2700 kg ha^?1, respectively. In coated and uncoated linuron plots, yields were 2920 and 2340 kg ha^?1, respectively. Except for the uncoated linuron plot, all yields were significantly higher than 2050 kg ha^?1 obtained in the weedy untreated plot.     

麦田新型除草剂砜吡草唑的除草活性

杂草严重影响小麦的丰产丰收,而使用除草剂是麦田杂草防除中最经济有效的手段。砜吡草唑是新型广谱、高活性的苗前土壤处理除草剂。明确砜吡草唑对麦田杂草的除草活性是该药剂在麦田应用的重要内容。本文采用温室盆栽法研究了其对麦田常见杂草的杀草谱及除草活性。研究结果表明:砜吡草唑土壤处理对麦田禾本科杂草鹅观草Roegneria kamoji、多花黑麦草Lolium multiflorum、雀麦Bromus japonicus、棒头草Polypogon fugax、蜡烛草Phleum paniculatum,阔叶杂草大巢菜Vicia sativa、播娘蒿Descurainia sophia、麦家公Lithospermum arvense、泽漆Euphorbia helioscopia具有良好的防除效果,但对节节麦Aegilops tauschii和野燕麦Avena fatua的防除效果略差。在推荐剂量180 g/hm^2下,对鹅观草、多花黑麦草、雀麦、棒头草、蜡烛草、大巢菜、播娘蒿、麦家公、泽漆的株抑制率和鲜重抑制率均可达到90%以上。而对节节麦和野燕麦的ED 90分别为209.54和886.43 g/hm^2,高于砜吡草唑的田间推荐剂量。砜吡草唑具有广泛的杀草谱及较高的除草活性,可作为小麦田杂草化学防除的重要候选药剂。     

Identification of a bacterium isolated from galls on carrot and weeds

In 2004, bacterial galls were found on the roots of carrots in Shizuoka Prefecture, Japan. Galls were about 0.1–2 cm in diameter, light brown in color and had rough surfaces. In 2005, similar galls were found on the roots of three weeds: henbit (Lamium amplexicaule L.), Persian speedwell (Veronica persica Poir.) and leaf mustard (Brassica juncea L.). A bacterium that forms white, rough colonies was isolated from the carrot and weeds galls. The bacterial isolates had properties identical with Rhizobacter dauci Goto and Kuwata. Phylogenetic analysis based on 16S rDNA sequences showed that the carrot isolate had the highest homology (similarity of 100%) with that of the type strain of R. dauci. Rep-PCR genomic fingerprinting using BOX A1R primer showed that the carrot and weeds isolates were nearly identical. Pathogenicity of the isolates was confirmed by inoculating the roots of carrots and the weeds. After 2–5 weeks, they formed galls on the roots of the original host species and on other plant species tested. The galls were indistinguishable from those formed naturally, and the inoculated bacterium was reisolated. Thus, the causal bacterium of carrot and weeds gall was identified as R. dauci, and the bacterium was found to have a wider host range than previously known. These weed hosts may serve as inoculum sources for carrot bacterial gall disease.     

Influence of environmental factors on the performance of sethoxydim against Elymus repens (L.)

The performance of sethoxydim on Elymus repens (L.) Gould was studied under contrasting levels of humidity, light intensity, temperature, soil moisture and simulated rainfall using controlled environment chambers. Over a 24-h post-spraying period, increases in humidity and temperature markedly enhanced herbicide performance, while effects of light intensity were less pronounced. Soil moisture deficit significantly reduced herbicide performance, but there were no adverse effects of wet soil conditions (twice field capacity) on activity. The effects of simulated rain depended upon herbicide dosage, time interval between spraying and the onset of rain, and rain intensity. A low rain intensity of 0.5 mm h^?1 did not reduce herbicide performance even when applied 10 min after spraying. The longer term studies, over 4 weeks, showed increases in herbicide activity with higher temperatures but lower light intensities.     

Chemical control of Eleusine indica and other weeds in Setaria anceps

In field experments on the Altherton Tableland. Queensland. Auslralia, methabenzthiazuron used at 1 2 kg ha pre-emergence was the most effective herbicide for selectively controlling Eleusine indica (L.) Gaertn in seed crops of Setaria anceps Stapf. Bromoxynil. bromoxynil plus MCPA, simazine and terbutryne were either ineffective or phytotoxic to S anceps. A more reliable technique was the use of diuron applied at 2.8 kg ha pre-emergence when the crop row was physically protected with metal shields at spraying or when activated carbon applied as a slurry in water at 168 kg per sprayed ha was sprayed in a 3 cm wide band over the crop row at sowing Three successive applications of paraquat over a 39 day period prior to sowing the crop were necessary for effective control of E. indica using the ‘stale seed bed’ technique     

Uptake, translocation and metabolism of aminocyclopyrachlor in prickly lettuce, rush skeletonweed and yellow starthistle

BACKGROUND: Aminocyclopyrachlor is a new herbicide proposed to control broadleaf weeds and shrubs in non‐crop and rangeland systems. To gain a better understanding of observed field efficacy, the uptake and translocation of foliar‐applied aminocyclopyrachlor (DPX‐MAT28) and aminocyclopyrachlor methyl ester (DPX‐KJM44) were evaluated in two annuals, prickly lettuce (Lactuca serriola L.) and yellow starthistle (Centaurea solstitialis L.), and one perennial, rush skeletonweed (Chondrilla juncea L.). RESULTS: Absorption and translocation varied between species. While absorption of DPX‐KJM44 was greater than absorption of DPX‐MAT28, rush skeletonweed absorbed the most, followed by yellow starthistle and prickly lettuce. Overall, the total translocation of either herbicide was highest in yellow starthistle, followed by rush skeletonweed and prickly lettuce. Proportional herbicide movement between species was similar, with the majority translocating to developing shoots. However, in rush skeletonweed, early translocation was directed to root tissue. In rush skeletonweed, no DPX‐MAT28 metabolism occurred, while DPX‐KJM44 was rapidly de‐esterified and translocated as DPX‐MAT28. CONCLUSION: Aminocyclopyrachlor absorption and translocation are dependent on active ingredient structure and species sensitivity. Highly sensitive species such as prickly lettuce absorb and translocate less material than relatively less sensitive species such as rush skeletonweed. De‐esterification of DPX‐KJM44 appears to delay translocation of the resulting acid in yellow starthistle and rush skeletonweed. Copyright © 2011 Society of Chemical Industry     

Performance of pyrazosulfuron-ethyl in non-puddled transplanted rainy season rice and its residual effect on growth of the succeeding crop in rice-wheat cropping pattern

Abstract

A study was carried out in sandy clay loam textured soil of Mymensingh, Bangladesh to evaluate weed control efficiency of pre-emergence herbicide pyrazosulfuron-ethyl either alone or in sequential application with post-emergence herbicide in transplanted rainy season rice under non-puddled strip-tilled (NPST) field condition and also to examine the residual effect of those herbicides on germination and growth of the subsequently grown wheat crop. Five treatment combinations of pyrazosulfuron-ethyl were tested against one weedy check and one weed-free check. The study revealed that NPST rice field was mostly infested by grass and sedge weeds and herbicide treatments offered a wide range of control (above 50% to 95%) on all types of weeds. Application of pyrazosulfuron-ethyl followed by (fb) orthosulfamuron fb butachlor plus propanil provided the most effective and economic weed control over two years of the study. Moreover, micro-plot bioassay study claimed germination and growth of subsequently grown wheat were not adversely affected by herbicides that were applied in rice. Therefore, application of pyrazosulfuron-ethyl followed by post-emergence herbicide could be effective and economic to control weeds in NPST rice under rice-wheat system, but proper rate and time of application should strictly be followed.     

Tillage implement effects on herbicide efficacy and the yield of cotton grown under a sprinkler or drip irrigation system

Field experiments were conducted during 2003 and 2004 at four locations in northern Greece to evaluate the effects of tillage implements and herbicide treatments on the weed control and yield of cotton grown under a mobile sprinkler or drip irrigation system. The tillage implements consisted of three seedbed preparation tillage implements: a field cultivator with a double rolling basket, a disk harrow or a rotary harrow. The herbicide treatments consisted of a broadcast preplant-incorporated (PPI) application of trifluralin or S-metolachlor followed by pre-emergence (PRE)-applied prometryn, a PRE 38 cm band application of S-metolachlor plus fluometuron or a broadcast PPI application of S-metolachlor followed by early postemergence-applied trifloxysulfuron-sodium. In most cases, the PPI applications followed by the PRE application of prometryn resulted in the greatest control of black nightshade ( Solanum nigrum L.), redroot pigweed ( Amaranthus retroflexus L.), and common lambsquarters ( Chenopodium album L.). The control of black nightshade and common lambsquarters was slightly reduced when the herbicides were incorporated by rotary harrow. The cotton yield was not affected in most cases by the tillage implements, while the drip irrigation system provided a greater or similar cotton yield as compared with the sprinklers. The PPI application of trifluralin followed by the PRE-applied prometryn in the cotton grown under drip irrigation provided the greatest lint yield in most cases. Therefore, a drip irrigation system and disk harrow or field cultivator implement could be used as the first choice of cotton growers in integrated crop management production systems.     

The Royal Show

Abstract

A non-mechanical system of applying herbicides to weeds taller than crops by a simple rope wick device is described. The herbicide applicator requires no pumps or moving parts to deliver the herbicide, and it can be built by the farmer at a very low cost. Selective control of johnsongrass (Sorghum halepense (L.) Pers.) in soyabeans (Glycine max (L.) Merr.) with glyphosate was demonstrated in two experiments under field conditions.