bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sublethal effects of chlorsulfuron on black bindweed (Polygonum convolvulus L.)
Authors: KJÆR C. 
Published: July 2006

Summary: Résumé: ZusammenfassungEffects of the herbicide chlorsulfuron on growth and reproduction of black bindweed (Polygonum convolvulus L.) plants were investigated in a controlled environment chamber and a greenhouse over a full life cycle. Biomass of P. convolvulus was stimulated at 0.4 g a.i. ha−1, but at higher doses it was reduced compared with controls. Leaf production of plants treated with 1.6 g a.i. ha−1 was initially totally inhibited, but these plants resumed leaf production 10 days after treatment. Chlorsulfuron treatment resulted in higher proportions of small and large leaves compared with controls. Because the life‐span of the plants increased with increasing doses of chlorsulfuron, seed production was not affected at doses up to 1.6 g ha−1, even though significant effects were found on both biomass and leaf production. At rates of 1.6–4 g a.i. ha−1 seed production decreased. Plant mortality was low in this study, reaching 33% at the highest rate of chlorsulfuron. Effets sublétaux du chlorsulfuron sur la renouée faux‐liseron (Polygonum convolvulus L.)Les effets du chlorsulfuron sur la croissance et la reproduction de la renouée faux‐liseron (Polygonum convolvulus L.) ont étéétudiés en serre et en conditions controlées sur un cycle complet. La biomasse de P. convolvulusétait stimulée à 0,4 g m.a. ha−1 mais à doses plus élevées elle était réduite par rapport à celle des témoins. La production de feuilles de plantes traitées à 1,6 g m.a. ha−1était initialement totalement inhibée mais ces plantes reprenaient leur production de feuilles 10 jours après le traitement. Les plantes traitées au chlorsulfuron avaient une plus grande proportion de feuilles petites et grandes que les témoins. Comme la durée de vie des plantes s'accroissait avec la dose de chlorsulfuron, la production de graines n'était pas affectée jusqu'à la dose 1,6 g m.a. ha−1, meme si des effets significatifs étaient détectés sur la biomasse et la production de feuilles. À des doses comprises entre 1,6 et 4 g m.a. ha−1, la production de graines diminuait. La mortalité des plantes était faible dans cette étude, atteignant 33%à la plus haute dose de chlorsulfuron. Subletale Wirkungen von Chlorsulfuron auf den Gemeinen Windenknoterich (Polygonum convolvulus L.)In Ecophyt‐ und Gewachshausversuchen zur Wirkung von Chlorsulfuron auf Wachstum und Reproduktion des Gemeinen Windenknoterichs (Polygonum convolvulus L.) war die Biomassebildung bei 0,4 g AS ha−1 verstarkt, bei hoheren Dosen jedoch verringert. Bei 1,6 g AS ha−1 war die Blattentwicklung zunachast fur 10 Tage nach der Behandlung ganzlich unterdruckt. Der Anteil kleinerer und großerer Blatter war hoher. Mit zunehmendem Aufwand des Herbizids verlangerte sich der Entwicklungszyklus, so daß bis zu 1,6 g AS ha−1 die Samenproduktion nicht zuruckging, trotz signifikanter Wirkung sowohl auf die Biomasse als auch auf die Blattbildung. Bei Dosen Uber 1,6 bis 4,0 g AS ha−1 wurden weniger Samen gebildet. Die Absterberate war bei diesen Versuchen niedrig und betrug bei der hochsten Chlorsulfuron‐Dosis 33%.
Soil‐incorporated trifluralin protects cotton (Gossypium hirsutum) from root‐absorbed herbicides
Authors: KLEIFELD Y. , RUBIN B. , BLUMENFELD T. , HERZLINGER G. , BUXBAUM H. , GOLAN S. 
Published: July 2006

Summary: Résumé: ZusammenfassungMechanical incorporation of a tank mixture of trifluralin in combination with fluometuron, diuron or prometryne in the soil to a depth of 10 cm protected emerging cotton from the damage caused by these herbicides in the absence of trifluralin. The incorporated tank mixtures, which were activated by sprinkler irrigation, controlled weeds which were tolerant to trifluralin alone. The different reaction of weeds and cotton to the soil‐incorporated herbicide mixtures corresponded to the reaction of their root systems to trifluralin. Weeds whose root system was shortened significantly by trifluralin were sensitive to the tank‐mixed, soil‐incorporated herbicides. La trifluraline incorporée au sol protége le coton (Gossypium hirsutum) des herbicides à absorption racinaireL'incorporation mécanique de mélanges de trifluraline avec du fluométuron, du diuron ou de la prométryne, à des profondeurs de sol 10 cm, protégeait le coton au moment de la levée contre les dommages occasionnés par ces herbicides en l'absence de trifluraline. Les mélanges incorporés, quiétaient activés par irrigation par aspersion, détruisaient les mauvaises herbes qui étaient tolérantes à la trifluraline seule. La réaction différente des mauvaises herbes et du coton aux mélanges d'herbicides incorporés correspondait à la réaction de leur système racinaire à la trifluraline. Les mauvaises herbes dont le systéme racinaire était raccourci par la trifluraline étaient sensibles aux mélanges d'herbicides incorporés. Schutz der Baumwolle (Gossypium hirsutum) vor wurzelabsorbierten Herbiziden durch eingearbeitetes TrifluralinNach Einarbeitung von Tankmischungen von Trifluralin mit Fluometuron, Diuron oder Prometryn bis in 10 cm Bodentiefe blieben Baumwoll‐Keimpflanzen von den sonst von diesen 3 letzgenannten Herbiziden verursachten Schaden frei, Mittels der Tankmischungen ließen sich gegenuber Trifluralin allein unempfindliche Unkrauter bekampfen. Die unterschiedliche Reaktion der Unkrauter und der Baumwolle auf die eingearbeiteten Herbizidmischungen entsprachen der Reaktion ihrer Wurzeln auf Trifluralin. Soweit die Entwicklung von Unkrautwurzeln durch Trifluralin signifikant gehemmt wurde, waren diese Arten gegenuber den eingearbeitenen Tankmischungen empfindlich.
Competitive ability and threshold levels of three broadleaf weed species in sunflower
Authors: ONOFRI A. , TEI F. 
Published: July 2006

Summary: Résumé: ZusammenfassungData collected from field trials carried out in different years and environments were used to determine competitive ability and threshold levels of Ammi majus L., Chenopodium album L. and Sinapis arvensis L. The hyperbolic model showed a good fit to the experimental data. The three broadleaf weeds showed low and similar competitive indices (i ranging from 1–08 to 1–75), supporting the hypothesis of a high sunflower competitive ability. The economic threshold was four to six plants m−2 for all three weeds in the case of weed control by hoeing and about six plants m−2 for S. arvensis in the case of a postemergence treatment with imazamethabenz. Limitations and approximations in estimating competitive parameters are pointed out and discussed. Aptitude à la compétition et seuils de nuisibilité de trois mauvaises herbes dicotylédones dans le tournesol Des données recueillies dans des expérimentations au champ conduites dans différents environnements et au cours de différentes années ont été utilisées pour déterminer l'aptitude à la compétition et les seuils de nuisibilité de Ammi majus L., Chenopodium album L. et Sinapis arvensis L. Le modéle hyperbolique fournissait un bon ajustement aux données. Les trois mauvaises herbes avaient des indices de compétition bas et similaires (i de 1,08 à 1,75) ce qui conforte l'hypothèse d'une forte aptitude à la compétition du tournesol.Les seuils économiques étaient 4–6 plantes m−2 pour toutes les mauvaises herbes dans le cas de désherbage mécanique et environ 6 plantes m−2 pour S. arvensis dans le cas de traitement de post‐levée avec l'imazaméthabenz.Les limitations et les approximations dans l'évaluation des paramètres de la compétition sont identifiés et discutés. Konkurrenzkraft und Schadensschwellen von drei dikotylen Unkrautarten in Sonnenblume Anhand von Ergebnissen aus Freilandversuchen in verschiedenen Jahren auf verschiedenen Standorten wurden die Konkurrenzkraft und die Schadensschwellen von Ammi majus L., Chenopodium album L., und Sinapis arvensis L, bestimmt. Die Ergebnisse ließen sich mit einer hyperbolischen Gleichung gut beschreiben. Die Konkurrenzindices i von 1,08 bis 1,75 waren fur alle 3 Arten ahnlich niedrig, worin sich die starke Konkurrenz der Sonnenblume widerspiegelt. Bei mechanischer Unkrautbekampfung lagen die Schadensschwellen fur alle 3 Unkrauter zwischen 4 und 6 Pflanzen m−2, fur Nachauflaufbehandlung mit Imazametabenz fur Sinapis arvenis bei 6 Pflanzen m−2. Grenzen und Annaherung der Bestimmung von Konkurrenzparametern werden eingehend diskutiert.
Interference between triazine‐resistant Brassica napus and Panicum miliaceum
Authors: MILLER T. W. , CALLIHAN R. H. 
Published: July 2006

SummaryAtrazine carryover often limits growers to production of atrazine‐tolerant crops the year following application, and allows the increase of triazine‐tolerant weed species such as Panicum miliaceum L. (wild proso millet). Tiriazine‐resistant Brassica napus L. cv. ‘Triton’ (oilseed rape) was tested to characterize the nature of interspecific interference with P. miliaceum. In a greenhouse study, atrazine at 2.2 kg ha−1 depressed oilseed rape fruit (siliqua) number and fruit dry weight, and delayed flowering, but did not significantly affect height or weight of shoots, Oilseed rape fruit weight was reduced at 200 P. miliaceum plants m−2. fruit number and shoot weight were inhibited at 400 weeds m−2. and height was reduced and flowering delayed at 600 weeds m−2. Number and weight of fruits were reduced by one‐third after 8 weeks of interference as compared to oilseed rape grown with the weed for 4 weeks. Oilseed rape height was reduced by 29% and shoot weight by 55% by 600 weeds m−2 and 2–2 kg ha−1 atrazine, while fruit number and weight were reduced by 72%. Oilseed rape shoot weight was reduced by 74% by 600 weeds m−2 for 12 weeks of interference, while fruit number and weight were reduced by 85% and 82%. respectively.In a field study, fluazifop reduced early season P. miliaceum cover by 72%, but did not increase oilseed rape cover. Mid‐season P. miliaceum shoot weight was decreased by 97% by fluazifop and oilseed rape shoot weight was increased by 34%. P. miliaceum control increased oilseed rape biomass by 38% at 89 days, but biomass of oilseed rape sown at 11.2 kg ha−1 with 2.2 kg atrazine ha−1 was not decreased by P. miliaceum interference at 89 days.
Volunteer barley interference in fibre flax (Linum usitatissimum L.)
Authors: MARSHALL G. , HACK CAROLINE M. , KIRKWOOD R. C. 
Published: July 2006

SummaryField experiments were conducted in 1989 and 1990 to determine the relationship between yield loss in fibre flax and the density of volunteer barley. At volunteer densities of 50–100 plants m−2, plants which emerged 7 days before those emerging synchronously with the flax produced a significantly greater reduction in stem height (1990), stem dry weight (DW) at flowering (1989 and 1990) and seed boll DW (1990). The relationships between flax stem and boll DW and volunteer density were described at two growth stages (flowering and maturity) using a linear model. The 1990 model indicated that where volunteer tiller densities ranged from 0 to 350 m−2, interference by 90 volunteer tillers m−2 (30 plants m−2) reduced stem DW by 2–9% at the flowering stage. These losses increased to 9–18% for stem DW plus 7–18% for seed boll DW when plants were grown to seed maturity. Due to the high value of flax fibres and seed it is concluded that an economic threshold based on the control of volunteer barley can be reached at low volunteer densities (30 plants m−2) especially if both fibre and oilseed were to be harvested.
Weed control in glyphosate‐tolerant sugarbeet (Beta vulgaris L.)
Authors: MADSEN K. H. , JENSEN J.E. 
Published: July 2006

SummaryThe effect of glyphosate on weeds was evaluated in greenhouse bioassays with five weed species and compared with a commercial mixture of phenmedipham and ethofumesate. Glyphosate was more active than a mixture of phenmedipham and ethofumesate on the weeds. Solanum nigrum was the most sensitive species to both herbicide treatments. The relative potency of glyphosate between the weeds showed consistency at 50% and 90% control levels for four out of five weed species, which could be ranked independently of control level because of similar response curves. In a field trial on sugarbeet genetically engineered to acquire glyphosate tolerance, a total of 720 g a.i. ha−1 of glyphosate applied in one, two or three applications gave similar or superior control of weeds to a total of 3.17 kg a.i. ha−1 mixture of metamitron, phenmedipham and ethofumesate applied in three repeated applications.
Resistance of dicot weeds to acetolactate synthase (ALS)‐inhibiting herbicides in Australia
Authors: BOUTSALIS P. , POWLES S. B. 
Published: July 2006

SummaryA biotype of Sonchus oleraceus L. and two bio types of Sisymbrium orientate Torn., SSO 3 and NSO 1, are the first dicot weeds in Australia to develop resistance to ALS‐inhibiting herbicides. The resistant biotypes had been exposed to va rying periods of selection with sulfonylurea her bicides. All three biotypes are resistant to a range of sulfonylurea and imidazolinone herbicides. The S. orientale biotypes are also resistant to the triazolopyrimidine herbicide, flumetsulam. LD50 ratios of resistant Sonchus oleraceus for sulfony lurea and imidazolinone herbicides are greater than 64‐fold and 4.5‐fold, respectively. GR50 ratios are greater than 9 for sulfonylureas and 7.4 for imazapyr. The LD50 ratios for both S. orien tale biotypes for chlorsulfuron, sulfometuron methyl, metsulfuron‐methyl, flumetsulam and imazethapyr are greater than 110‐, 15‐, 7‐, 24‐ and 29‐fold, respectively. All resistant biotypes are susceptible to MCPA, diuron and diflufenican, herbicides which do not inhibit ALS.
Growth, development and nutrient accumulation in Senecio vulgaris L. and Chenopodium album L.
Authors: QASEM J. R. , HILL T. A. 
Published: July 2006

SummaryGrowth, development and nutrient accumula tion in Chenopodium album and Senecio vulgaris grown in pure and mixed stands were investi gated through several experiments conducted under glasshouse conditions. Results showed that the two weeds were different in their growth, development and tissue concentration and accu mulation of mineral elements. The mean concen trations of nitrogen, phosphorus, potassium, calcium and magnesium in shoots of C. album were higher than those of S. vulgaris, while root concentrations of nitrogen, potassium and mag nesium were lower for C. album. Marked dif ferences between the two weed species in their responses to different potassium levels were found. C. album had a high specific requirement for potassium while the reverse was true for S. vulgaris. The competitive ability and accumula tion of nutrients by C. album appeared to be greatly dependent on the availability of high potassium levels in the media.
Growth characteristics of spring barley and selected weeds. I. Effect of irradiance in growth chambers
Authors: SEMB K. 
Published: July 2006

SummaryA study in growth chambers with three irradiance levels was carried out over a four‐week period on individual seedlings of spring barley (Hordeum vulgare L.) and five weed species (Brassica rapa L. ssp. oleifera (DC.) Metzger, Chenopodium album L., Galeopsis tetrahit L., Stellaria media (L.) Vill., and Viola arvensis Murray). Increased irradiance resulted in larger dry weight, net photosynthetic rate, relative growth rate (RGR), net assimilation rate (NAR), and lower leaf area ratio (LAR). The number of leaves per plant, plant length, leaf area, and shoot/root ratio were unaffected by irradiance levels, During the experimental period the net photosynthetic rate increased, while NAR remained the same, and RGR, LAR, and shoot/ root ratio decreased. On the basis of leaf area and dry weight, especially at the high irradiance level during the last part of the experimental period, barley, B. rapa, and C. tetrahit had the largest values, followed by C. album and S. media with medium values, and V. arvensis with the smallest values. As for leaf area and dry weight, S. media took more advantage of the low than the high irradiance level compared with C. album. Species differences are discussed with regard to competitive ability.
The effect of nitrogenous compounds on in vitro germination of Orobanche crenata Forsk.
Authors: VAN HEZEWIJK M. J. , VERKLEIJ J. A. C. 
Published: July 2006

SummaryThe effect of nitrogen (ammonium, urea and nitrate), applied during a conditioning or germination phase, on germination of Orobanche crenata Forsk, seeds was investigated in vitro. Ammonium sulphate (8 mM) applied during conditioning in combination with the nitrification inhibitor nitrapyrin, reduced germination of seeds from 46% to 26%. A lower concentration of 4 mM ammonium sulphate or supplying nitrogen as 8 mM urea or 16 mM nitrate did not inhibit germination. Applied after conditioning during the germination phase, 4 mM ammonium sulphate strongly inhibited germination, especially in combination with a nitrification inhibitor: germination was reduced to less than 5%. Urea (8 mM) reduced germination to only a limited extent (from 58% to 40%). When a urease inhibitor (carbon disulfide) was additionally applied, germination percentage was not affected. Nitrate had no effect. It is hypothesized that the inhibition by ammonium of O. crenata germination is connected with a reduced ability to detoxify ammonium, owing to the reduced activities of the enzymes GS and GOGAT. The inhibitory effect of urea may be indirect, occurring through conversion to ammonium. The effect of a short‐term exposure to ammonium was largely reversible and no increase in mortality could be detected. The presence of 6 mM phosphate, Hepes or Mops buffer was found to intervene with the inhibition by ammonium.
Alcoholysis and chemical hydrolysis of bensulfuron‐methyl
Authors: SABADIE J. 
Published: July 2006

SummaryAlcoholysis (methanol or ethanol) and hydrolysis (pH ≤ 8) of the herbicide bensulfuron‐methyl at 30 or 50^C involve only the breakdown of the urea part of the molecule. A high yield of the pyrimidinamine is always obtained, along with the corresponding carbamate (alcoholysis) or benzylsulfonamide (hydrolysis). The latter compound was easily cyclized (pH ≥ 6). In alkaline solution, the carbomethoxy substituent of the aromatic ring was preferentially hydrolysed. In all cases, the alcoholysis and hydrolysis rates could be described well with first‐order kinetics. Alcoholysis rate constants of bensulfuron‐methyl and bensulfuron ranged from 0.08 to 0.15 d−1 at 30^C. Hydrolysis rate constants of bensulfuron‐methyl, bensulfuron and benzylsulfonamide varied strongly with pH. The hydrolysis rate constant of bensulfuron‐methyl was minimal around pH 8. The hydrolysis rate constant of bensulfuron decreased with increasing pH, whereas that of benzylsulfonamide increased with increasing pH.
The importance of seeds and sexual reproduction in the population biology of Cirsium arvense ‐ a literature review
Authors: HEIMANN B. , CUSSANS G.W. 
Published: July 2006

SummaryIn this review the available information on the sexual reproduction of Cirsium arvense L. (Scop.) is summarized and discussed in an ecological context. Certain aspects of its sexual reproduction system have given C. arvense a reputation for low efficiency: the dioecious mating system and dependence on insects for pollination and non‐adaptive features for wind dispersal. The seeds are moderately persistent in soil and, for a temperate weed, have a high temperature requirement for germination. It is concluded that the contribution that sexual reproduction makes to the survival and spread of this species has been underestimated, partly owing to an inadequate number of studies. Seedling recruitment via sexual reproduction may be an important mechanism for initiating continued genetic diversity at intra‐ and inter‐population levels.
An assessment of the possible reasons for differential tolerance to fluroxypyr in selected populations of Galium aparine
Authors: HILL A. L. , COURTNEY A. D. , HARVEY B. M. R. 
Published: July 2006

SummaryIn an investigation of the possible reasons for tolerance lo fluroxypyr by Galium aparine L. (cleavers), a wide range of variation in total herbicide retention was exhibited by nine diverse populations from throughout Europe. Although these differences in fluroxypyr relention became negligible when considered on a unit area basis, a two‐fold difference was maintained per unit dry matter. There was no difference in fluroxypyr uptake between a fluroxypyr‐tolerant and a fluroxypyr‐susceptible population, and differences in translocation between the two populations did not seem to explain the differential tolerance. It is suggested that differential metabolic detoxification may be the main reason for the variation in response to fluroxypyr by populations of G. aparine.
Resistance of Amaranthus hybridus to atrazine
Authors: SEREDA B. , ERASMUS D. J. , COETZER R. L. J. 
Published: July 2006

SummaryResistance of weeds to triazine herbicides has been recorded in many countries. The extent of the problem in South Africa is uncertain. In a pilot study, the atrazine resistance of Amaranthus hybridus L. (smooth pigweed) was investigated. Suspected resistant (R) and susceptible (S) biotypes were treated with commercially formulated atrazine. After post‐and pre‐emergence applications under tunnel conditions, it was found that the suspected R biotype plants were not affected at herbicide dosages of belween 1.25 and 25.0 kg a.i. ha‐1, i.e. up to 20 times gieater than the lowest recommended dosage. However, the S biotype plants were killed by the lowest dosage. In the fieid, mortalities in the R biolype were not observed after post‐emergence applications of 1.25‐10.00 kg a.i. ha‐1. In contrast, all S biotype plants were killed. In tunnel experiments, the R biotype was also found to be resistant to cyanazine and cyanazine+atrazine, while slight tolerance to linuron was observed. All these treatments resulted in 100% mortality of the S biotype. Although S biotype seeds oi A. hybridus were found to germinate slightly sooner under controlled conditions than R biotype seeds, preliminary results suggest that there are no major differences. Indications are that, although the growth of the S biotype may be greater than that of the R biotype, the competitive effect of the two biotypes on crop seedlings may well be similar.
Characteristics of seeds and seedlings from weeds treated with sublethal herbicide doses
Authors: ANDERSSON L. 
Published: July 2006

SummarySize, germination and viability of seeds as well as growth of seedlings derived from three weed species were studied in a pot trial. Fallopin convolvulus (L.) A. Loeve, Galium. spurium L. and Thlaspi arvense L. were treated with MCPA or tribenuron‐methyl at four doses and at five growth stages, from seedling stage to flowering, In G. spurium subnormal doses of tribenuron‐methyl, applied at intermediate growth stages, greatly reduced seed weight, gennination, viability, seedling shoot biomass and root biomass. Germination and viability, as well as the shoot biomass and root biomass of seedlings, were highly correlated with seed weight. In addition, but to a smaller extent, seed weight was reduced in F. convolvidus and T. arvense by tribenuron‐methyl and in G. spurium by MCPA. Germination was reduced in F. convolvulus by MCPA and in T. arvense by tribenuron‐methyl. However, the effects varied greatly depending on the growth stage at application.