bluuebunny/crossref_metadata_2025_split huggingface dataset:
Antagonistic effects of 2,4‐D amine and bentazone on control of Avena fatua with tralkoxydim
Authors: JENSEN K. I. N. , CASELEY J. C. 
Published: July 2006

Summary:Control of Avena fatua with tralkoxydim was significantly reduced in glasshouse experiments when the herbicide was tank‐mixed with either 2,4‐D amine or bentazone. Antagonism increased with increasing rates of these broadleaf herbicides in the tank‐mixture and it could, in turn, be decreased by increasing rates of tralkoxydim. When herbicide solutions were applied to single leaves with a micropipette applicator, bentazone was antagonistic only when mixed in the same droplet with tralkoxydim and not when the two herbicides were applied adjacently in separate droplets. In contrast, both separate and combined applications of 2,4‐D amine and tralkoxydim were antagonistic. There was no antagonism when mixtures with either 2,4‐D amine or bentazone were applied between the leaf sheath and culm. Antagonism could be circumvented by sequential applications of the herbicides. When tral‐oxydim was applied first, there was no loss of A. fatua control if bentazone application was delayed 0.5 h or if 2,4‐D amine was delayed 24 h. Results suggest that bentazone affects only cuticular penetration of tralkoxydim, whereas 2,4‐D amine also influences subsequent translocation.
Competition for light between velvetleaf (Abutilon theophrasti) and soybean (Glycine max)
Authors: AKEY W. C. , JURIK T. W. , DEKKER J. 
Published: July 2006

Summary:We examined factors affecting conversion of light into dry matter of velvetleaf (Abutilon theophrasti) and soybean (Glycine max) grown in a replacement series near Ames, Iowa, U.S.A. in 1986 and 1987. Velvetleaf was taller than soybean over most of the growing season and had more branches, especially at the top of the canopy. Velvetleaf had greater light interception than soybean in the upper part of the canopy, particularly early and late in the day, although total light interception by canopies of the two species was similar on most sample dates. Velvetleaf had higher light utilization efficiency, or conversion of intercepted light into dry matter, in the middle and later part of the growing season. This combination of traits appears to give velvetleaf an advantage over soybean in competition for light.
Penetration of clopyralid and related weak acid herbicides into and through isolated cuticular membranes of Euonymus fortunei
Authors: KLOPPENBURG D. J. , HALL J. C. 
Published: July 2006

Summary:A model system consisting of chemically isolated cuticular membranes placed on agar was used to study the penetration of various formulations of 14C‐labelled clopyralid, fluroxypyr, triclopyr, picloram, and 2,4‐D into and through cuticular membranes. Clopyralid, commercially formulated as the acid, or 1‐decyl ester was rapidly absorbed after 12 h by isolated cuticles of Euonymus fortunei. There was less absorption of the monoethanolamine and potassium salt formulations when compared to the acid and 1‐decyl ester. However, in terms of the absorbed 14C‐activity that partitioned into the agar, there was no difference between the acid and salt formulations with approximately 90% being partitioned after 48 h. Conversely, the 1‐decyl ester formulation of clopyralid was retained in the cuticle; less than 5% of the absorbed fraction was recovered in the agar after 48 h. When the acid forms of clopyralid, fluroxypyr, triclopyr, picloram, and 2,4‐D were compared, there was little or no difference in absorption among the herbicides. However, the 14C‐activity from clopyralid partitioned the most (90%) and triclopyr the least (50%) into the agar. When ester formulations of clopyralid, fluroxypyr, and triclopyr were compared, at least 95% of the 14C‐activity was absorbed 24 h after application. However, of the amount absorbed, significantly more of the butoxyethyl ester of triclopyr (36%) partitioned into the agar than did the 1‐decyl ester of clopyralid (6%) or the 1‐methylheptyl ester of fluroxypyr (5%). Differential retention of various herbicide formulations in this model system may explain, in part, the differences in absorption and translocation among radiolabelled clopyralid formulations observed in previous research (Kloppenburg & Hall, 1990).
Dynamics and control of Sorghum halepense (L.) Pers. shoot populations: a test of a thermal calendar model
Authors: VITTA J. I. , LEGUIZAMÓN E. S. 
Published: July 2006

Summary:The dynamics of Sorghum halepense tiller emergence and rhizome biomass were studied in field experiments. The effect of different application dates of a post‐emergence herbicide on crop yield was measured. The relationship between accumulated thermal units (A.T.U.) and the percentage of emerged tillers in soybean was described by a single non‐linear regression model, independent of initial bud density. The estimates of population density were generally higher than those predicted by the original model developed by Satorre, Ghersa & Pataro (1985). In the absence of a crop, the higher the density of the weed the more concentrated the tiller emergence in the early part of the tillering period. The rhizome biomass reached a minimum value at about 230°C days, and was independent of the initial weed density. The maximum herbicide efficiency was achieved when the application was performed closest to the period of minimum rhizome biomass. The results show the feasibility of optimizing S. halepense control by calculating the period f minimum rhizome biomass. Such a criterion ls consistent with the maximization of crop yields.
Effect of low temperatures on 2,4‐D behaviour in maize plants
Authors: GAUVRIT C. , GAILLARDON P. 
Published: July 2006

Summary:The foliar surface of 4‐leaf maize plants was found to be poorly wettable and retained 106 μl g−1 dry matter when sprayed with a U46D (2,4‐D formulation) blank. The third leaf retained 141 μl g−1. A 7‐day cold spell (17/9°C) increased retention per unit dry matter by 53% (135% on the third leaf). Cold stress lowered epicuticular wax quantity by 29% on the third leaf. Contact angles of formulated 2,4‐D lay between 115 and 125° and were not significantly affected by cold stress. 2,4‐D rapidly entered into maize third leaf (66% in 24 h) but migration from it was less than 1.5%. 2,4‐D was readily degraded in maize (80% in 72 h). The most abundant metabolite was probably an ester conjugate; little of the hydroxy derivatives were found. Cold stress reduced 2,4‐D degradation, and 72 h after treatment the amount of undegraded 2,4‐D was 78% higher in cold‐stressed maize plants. It was concluded that 2,4‐D selectivity in maize results from low spray retention per unit dry matter and active degradation of penetrated herbicide. Cold stress affects both factors.
Survey of herbicide residues in soil and wells in three citrus orchards in Valencia, Spain
Authors: de BARREDA D. Gómez , LORENZO E. , GAMÓN M. , MONTEAGUDO E. , SAEZ A. , de la CUADRA J. D. , del BUSTO A. , RAMOS C. , CARBONELL E.A. 
Published: July 2006

Summary:Soil samples taken in summer 1989 and winter 1990 at different depths from three citrus orchards of the Valencia region (Spain) with a long history of residual herbicide treatments were analysed with bioassays and chromatographic procedures. The herbicides involved were atrazine, bromacil, diuron, simazine, terbuthylazine, terbumetone, terbutryn and trifluralin. Water samples from wells in the orchards were also analysed. The concentrations of the herbicides were very low, often below the limit of determination, and were always highest in the upper layers of soil. After a very unusual period of heavy rain, small quantities of some chemicals were found in the well water. The conclusion was that in these orchards the herbicides applied at currently used rates are unlikely to accumulate in any layers of the soil.
Soil properties affecting the distribution of 37 weed species in Danish fields
Authors: ANDREASEN C. , STREIBIG J. C. , HAAS H. 
Published: July 2006

Summary:The distribution of 37 common weed species in eight common Danish crops in response to seven edaphic factors was evaluated using linear logistic regression with adjustment for over‐dispersion. The main effects of soil properties on weed distribution were adjusted for crop type and sample year by the regression. Crop type and soil clay content were generally those explanatory variables that had the greatest influence on occurrence of the weed species, but all other factors examined (sample year, loss on ignition, pH, P, K, Mg and Mn) also had an effect on the occurrence of some weed species.
Selection of sorghum (Sorghum bicolor (L.) Moench) varieties resistant to the parasitic weed Striga hermonthica (Del.) Benth
Authors: OLIVIER A. , RAMAIAH K. V. , LEROUX G. D. 
Published: July 2006

Summary:Pot and field experiments were performed in Burkina Faso in 1987 and 1988 to evaluate the resistance of selected ‘low‐stimulant’ sorghum (Sorghum bicolor (L.) Moench) varieties to the parasitic weed (Striga hermonthica (Del.) Benth. In a pot experiment, the variety IS‐7777 supported the lowest number and had the latest emergence of Striga, compared with the other varieties tested. The varieties IS‐14825, IS‐6961, IS‐7739, IS‐14928 and IS‐14975 also had signifi cantly lower numbers of emerged Striga per pot than the resistant control Framida. The resist ance of IS‐7777 was confirmed in field experi ments, as was that of IS‐7739, IS‐6961 and IS‐14928. However, the yield potential of these poorly adapted varieties was low in Striga‐infested fields. The varieties IS‐14975, IS–14825 and Seguetana Niarabougou exhibited a low susceptibility associated with a grain yield equivalent to that of the other varieties in farm fields infested by Striga. As Seguetana is already grown by Sahelian farmers, its use could be recommended in the absence of resistant varieties adapted to Sahelian agroclimatic conditions. The exceptionally high level of restance exhibited by IS‐7777 could be exploited in studies on the genetics and mechanisms of resistance of the host plant to the parasite, as well as in sorghum improvement programmes.
MALHERB: ein Computerprogramm zur Bestimmung von Ackerunkräutern
Authors: LONCHAMP J.‐P. , BARRALIS G. , GASOUEZ J. , JAUZEIN P. , KERGUELEN M. , LE CLERCH J. , MAILLET J. 
Published: July 2006

Résumé:MALHERB est un logiciel de reconnaissance des mauvaises herbes des cultures. Ce logiciel permet la détermination, au stade adulte, de 490 espèces dont 82 graminées. Il utilise différentes descriptions d'une même espèce tenant compte de la variabilité intra‐spécifique et des difficultés de reconnaissance de certains organes. Les notions botaniques ne sont pas indispensables pour l'utilisation du logiciel. MALHERB gère une base de connaissances constituée essentiellement de 2 fichiers distincts contenant des ‘Plantes feuillées à port de graminées’ et des ‘Plantes feuillées à port different’. Les fichiers comportent, d'une part la description d'espèces à partir de caractères morphologiques et, d'autre part, des données ecologiques concernant leur répartition géographique, les cultures, le pH, la texture du sol auxquels elles sont associées. Le logiciel détermine d'abord des groupes d'espèces ayant en commun certains caractères, puis propose a l'utilisateur une clé spécifique à chaque groupe. Dans le cas où l'échantillon ne comporte pas certains organes necessaires à la détermination, MALHERB propose alors une reconnaissance fondée sur la comparaison de profils de caractères écologiques stationnels conduisant à un classement de vraisemblance (théorie de comparaison d'ensembles flous).
Sugarbeet tolerance and weed control efficacy with split applications of phenmedipham plus desmedipham
Authors: NORRIS R. F. 
Published: July 2006

Summary:Sugarbeet and weeds were treated with phenmedipham plus desmedipham either as single applications or as split applications in which 50% of the equivalent single application rate was applied at each application. Split application did not alter the phytotoxicity to the crop when environmental conditions did not predispose the Sugarbeet to injury by the herbicide. Split applications at 1‐1 or 1‐4 kg ha−1 spaced from 0‐5 to c. 5 days apart caused more injury to the crop than the respective single applications when environmental conditions were such that injury to the crop resulted from the single applications. Injury to Sugarbeet following application of 0‐72 kg ha−1 of phenmedipham plus desmedipham was always low, regardless of the type of application. Susceptible weeds were controlled by single applications of 1 1‐1 −4 kg ha−1, but 0‐72 kg ha−1 did not reliably provide adequate control. Split applications c. 3‐8 days apart gave improved control. Control achieved by 0‐72 kg ha−1 of the herbicide applied as split treatments equalled or exceeded that produced by single applications of 1‐4 kg ha−1. Improvement in the control of tolerant weed species by split applications of phenmedipham plus desmedipham was species dependent. Use of low‐rate split applications of phenmedipham plus desmedipham thus resulted in reduced injury to the Sugarbeet, and the introduction of less herbicide into the ecosystem, while maintaining or improving the control of susceptible weeds.
Long‐term stability of distribution of Alopecurus myosuroides Huds. within cereal fields
Authors: WILSON B.J. , BRAIN P. 
Published: July 2006

Summary:The incidence of Alopecurus myosuroides seedheads was monitored annually for 10 years in the cereal fields of a 173‐ha arable and dairy farm. A. myosuroides persisted at low population densities, despite the use of herbicides and grass breaks in the rotation. The distribution of the weed was irregular, with none occurring on at least 60% of the positions surveyed in the cereal fields. Spatial distributions were compared between years, and some significant correlations were found from year to year in continuous cereals, and in cereal crops separated by a 3‐year grass ley.
Frequency distribution of weed counts and applicability of a sequential sampling method to integrated weed management
Authors: BERTI A. , ZANIN G. , BALDONI G. , GRIGNANI C. , MAZZONCINI M. , MONTEMURRO P. , TEI F. , VAZZANA C. , VIGGIANI P. 
Published: July 2006

Summary: Résumé: ZusammenfassungWeed density was sampled in a number of quadrats in five crops and at eight locations in Italy. For every location and species of crop and weed, a mean/variance pair was calculated. The relationship between these two parameters was significantly influenced by crop and, to a lesser extent, by site, but not by species of weed. The goodness of fit of the negative binomial distribution to the samples was assessed. Its k exponent was estimated on the basis of the observed variance/mean regression. A good fit was found for weed populations with fewer than 10 plants m−2. The applicability of a sequential sampling procedure based on the negative binomial distribution to a weed control strategy that uses a threshold density is discussed. Denombrement de la fréquence des adventices et applicabilité a une méthode d'échantillonnage séquentiel pour un desherbage integré La densité en adventices a étééchantillonnée dans plusieurs cadres dans 5 cultures et à 8 endroits en Italic. Pour chaque lieu et espèce de culture et de mauvaise herbe un couple moyenne/variance a été calculé. La relation entre ces deux paramètres était très dépendante de la culture et à un degré moindre du lieu, mais n'était pas influencé par l'espèce d'adventice. La validité de l'application de la distribution binomiale négative aux échantillons a été estimée. Son coefficient k était estimé sur la base de la regression observée sur variance/ moyenne. Une bonne adéquation a été mise en évidence pour des populations inférieures à 10 plantes m−2 L'applicabilité d'un protocole d'échantillonnage séquentiel basé sur la distribution binomiale négative, à une stratégic de désherbage utilisant un seuil de densité est discutée. Frequenzverteilung in Unkraut‐Vegetationsaufnahmen und Aufnahmemethode im Rahmen der integrierten Unkrautbekämpfung Auf der Basis der Dichte von Unkräutern in 5 Kulturen an 8 Orten in Italien wurden Mittelwert und Varianz berechnet. Das Verhältnis dieser beiden Parameter wurde durch die Kulturpflanzenart signifikant, weniger durch den Ort und gar nicht durch die Unkrautart beeinflußt. Die Güte der Anpassung an dienegative Binomialverteilung der Erhebungsdaten wurde bestimmt. Ihr k‐Exponent wurde nach der beobachteten Varianz/Mittelwerts‐Regression bestimmt. Für Populationsdichten von < 10 Pflanzen m−2 ergab sich eine gute Anpassung. Die sich aus der negativen Binomialverteilung ergebende Bekämpfungsstrategie aufgrund von Schadensschwellen wird diskutiert.
Potential use of activated carbon as a protectant against pre‐emergence herbicides in direct‐seeded processing tomatoes
Authors: MORGAN W. C. , MORGANS A. S. 
Published: July 2006

Summary: Résumé: ZusammenfassungActivated carbon protected direct‐seeded tomato (Lycopersicon esculentum Mill., cv. UC 82B) against pre‐emergence applications of metribuzin and metolachlor, but not of oxyfluorfen or oxadiazon. Accurate placement of activated carbon on the soil surface directly above the seed was necessary for protection of tomato seedlings. Displacement of the carbon by overhead watering reduced its protective properties. A major disadvantage of the technique is that weed seeds under the activated carbon are also protected. Also, of the chemicals examined here, those against which it did provide protection did not control Solanum nigrum L. Utilisation potentielle du charbon actif comme phytoprotecteur des tomates conduites en semis direct contre les herbicides de prelevee Le carbone actif a protege des tomates en semis direct (Lycopersicon esculentum Mill., cv UC 82 B) contre des applications de prelevee de metribuzine et de metolachlor mais pas d'oxy‐fluorfen ou oxadiazon. Une locahsation précise du charbon actif sur la surface du sol directe‐ment au dessus de la graine est necessaire pour la protection des plantules de tomate. Le déplacement du charbon par arrosage réduit ses propriétés de protection. Un inconvénient important de la technique est que les graines d'adventices sous le charbon actif sont égale‐ment protégées. En outre, les produits chimiques examinés ici qui assurent une protection, ne sont pas actifs contre Solanum nigrum L. Aktivkohle als Schutzmittel gegen Vorauflauf‐Herbizide in gesdten Tomaten Mit Aktivkohle konnten gesate Tomaten (Lycopersicon esculentum Mill., ‘UC 82B’) gegen die Vorauflauf‐Anwendungen von Metribuzin und Metolachlor geschutzt werden, jedoch nicht gegen Oxyfluorfen oder Oxadiazon. Fur den Schutz der Tomaten‐Keimpflanzen mußte die Aktivkohle ganz genau uber den Samen auf die Bodenoberflache ausgebracht werden. Ver‐schwammen der Kohle durch Beregnung reduzierte ihre Schutzwirkung. Ein großer Nachteil dieser Methode liegt darin, daß keimende Unkrauter unter der Aktivkohle ebenso geschutzt werden. Auch konnte mit den hier untersuchten Herbiziden Solanum nigrum L. nicht bekampft werden.
Translocation, metabolism and residues of fluazifop‐butyl in soybean plants
Authors: BALINOVA A. M. , LALOVA M. P. 
Published: July 2006

Summary: Résumé: ZusammenfassungTranslocation of fluazifop‐butyl in soybean plants and hydrolysis of the ester to fluazifop‐acid were investigated in a field experiment. The herbicide was translocated rapidly from the leaves to the roots, but the concentration in the leaves remained about 10‐fold higher than that in the roots. Rapid hydrolysis of fluazifop‐butyl to fluazifop‐acid was observed, and residues of the metabolite were found to persist much longer in the plant than the active compound. Increased temperatures resulted in more rapid hydrolysis. No traces of active compound or of its main metabolite were found in the seeds after harvest. A reversed‐phase HPLC method for simultaneous détérmination of fluazifop‐butyl and fluazifop‐acid residues in soybean plants was developed. Transport, metabolisme et residus du fluazifop‐butyl chez les plantes de soja Le transport du fluazifop‐butyl dans les plantes de soja et l'hydrolyse de Tester en fluazifop‐acide ont étéétudiés dans une experimentation de plein champ. L'herbicide a été vehiculé rapidement des feuilles vers les racines, mais la concentration dans les feuilles est demeurée 10 fois plus haute que celle dans les racines. Une hydrolyse rapide de la forme ester en acide a été observee, et les residus du metabolite se sont reveles beaucoup plus persistants dans la plante que le composé actif. Une augmentation des températures a accéléré l'hydrolyse. Aucunes traces de la matière active ou de son principal métabolite n'ont été trouvées dans les graines après la récolte. Une methode HPLC en phase inverse pour la détérmination simultanée des residus de fluazifop‐butyl et de fluazifop‐acide chez le soja a été développée. Translokation, Metabolismus und Ruckstande von Fluazifop‐butyl in Sojabohnen‐Pflanzen Die Translokation von Fluazifop‐butyl in Sojabohnen‐Pflanzen und die Hydrolyse des Esters zu Fluazifop‐Saure wurden in einem Freilandversuch untersucht. Das Herbizid wurde von den Blattern in die Wurzein schnell transloziert, doch in den Blattern blieb die Konzentration etwa 10mal großer als in den Wurzein. Es wurde eine schnelle Hydrolyse des Fluazifop‐butyls zu Fluazifop‐Saure beob‐achtet, und die Ruckstande des Metaboliten in den Pflanzen erwiesen sich als viel bestandiger als der Wirkstoff. Bei hoheren Temperaturen lief die Hydrolyse schneller ab. In den Samen wurden nach der Ernte keine Ruckstande des Wirkstoffs oder seiner Hauptmetaboliten gefunden. Eine Reversed‐Phase‐HPLC‐Methode zur gleichzeitigen Bestimmung von Ruckstanden von Fluazifop‐butyl und Fluazifop‐Saure in Sojabohnen‐Pflanzen wurde entwickelt.