bluuebunny/crossref_metadata_2025_split huggingface dataset:
Factors affecting the development of populations of Oxalis pes‐caprae L.
Authors: LANE D. 
Published: July 2006

SummaryAs the control of Oxalis pes‐caprae L. is dependent upon treatment after the parent bulb has become exhausted and before the new bulbs have formed, experiments were conducted to test the uniformity of development of plants and to determine if adequate control could be expected from a single herbicide application. Inherent differences were observed in the time of emergence, and further differences could be induced by increasing the depth of planting or withholding water. Competition between plants was shown to retard the development of late‐emerging plants.The physical removal of parts of the plant before bulb exhaustion had limited effect on bulb production, but reduced bulb weights and numbers when carried out after bulb exhaustion. Although not all parts of the plant were replaced by regrowth, no major changes in overall development were noted.
Critical period of weed competition in three vegetable crops in relation to management practices
Authors: WEAVER SUSAN E. 
Published: July 2006

SummaryThe critical period of weed competition was determined in three vegetable crops: early cabbage (Brassica oleracea var. capitata L.), pickling cucumbers (Cucumis sativus L.), and field‐seeded processing tomatoes (Lycopersicon esculentum L.). There were significant interactions between weed‐removal treatments, year, and row width. Cabbage yields were reduced if plots were not kept weed‐free for at least 3 weeks after transplanting or if weeds which emerged with the crop were allowed to remain longer than 4–5 weeks, Cucumber yields were reduced if plots were not kept weed‐free for up to 4 weeks after seeding or if plots remained weed‐infested longer than 3–4 weeks. Higher crop population densities (narrower row widths) in cabbage and cucumbers resulted in smaller plants, earlier competition from weeds, and therefore a shorter period that the crop could remain weed‐infested without suffering reduced yields. Yields of direct‐seeded tomatoes were reduced if plots were not kept weed‐free for up to 9 weeks after seeding or if weeds which emerged with the crop were allowed to remain longer than 5 weeks. In each crop the timing of the critical period of competition was verified by weed removal only during this interval. There was a true critical period in direct‐seeded tomatoes, but not in cabbage or cucumbers where a single weeding was sufficient to prevent yield losses.
Effect of temperature during burial on dormant and non‐dormant seeds of Lamium amplexicaule L. and ecological implications
Authors: BASKIN J. M. , BASKIN CAROL C. 
Published: July 2006

SummarySpring‐produced seeds of Lamium amplexicaule L. were dormant at maturity in May and after‐ripened when buried and stored over a range of temperatures, becoming conditionally dormant at low (5, 15/6 and 20/10°C) and non‐dormant at high (25/15, 30/15 and 35/20°C) temperatures. Conditionally dormant seeds germinated to high percentages at 5 and 15/6°C, and non‐dormant seeds germinated to high percentages at 5, 15/6, 20/10, 25/15 and 30/15°C. Seeds that became conditionally dormant at 5°C afterripened completely (i.e. became non‐dormant) after transfer to 30/15°C. Buried seeds that became non‐dormant in a non‐temperature‐controlled glasshouse during summer were still non‐dormant after 12 weeks of storage at 30/15°C, while those stored at 5°C for 12 weeks had entered conditional dormancy. Thus, low temperatures cause reversal of the afterripening that takes place at high temperatures, but not that which takes place both at low and at high temperatures. Low winter temperatures cause dormant autumn‐produced seeds and non‐dormant seeds in the soil seed pool to become conditionally dormant. The ecological consequences of these responses to temperature are discussed in relation to the timing of seed germination in nature.
Influence of metolachlor and the metolachlor protectant CGA 43089 on the biosynthesis of epicuticular waxes on the primary leaves of Sorghum bicolor Moench
Authors: EBERT E. , RAMSTEINER K. 
Published: July 2006

SummaryEpicuticular wax synthesis by the primary leaf of Sorghum bicolor seedlings is inhibited when the germinating seeds are treated with 5 ppm metolachlor before germination. The composition of the free and esterified primary alcohols plus free and esterified fatty acids and aldehydes have been analysed. The predominant alcohol (75%) had 32 carbons while the 28‐ and 30‐carbon homologues accounted for 78% of the fatty acids. Treatment of the germinating seeds with metolachlor strongly inhibited formation of the C28, C30 and C32 alcohols. Synthesis of C30 and C32 fatty acids was decreased while that of the C26 homologues was somewhat elevated. Simultaneous treatment of the germinating seed with metolachlor and the herbicide protectant CGA 43089 (α‐[cyanomethoximino]‐benzacetonitrile) resulted in normal wax synthesis. The results lead to the conclusion that the protectant prevents metolachlor from inhibiting synthesis of the dominating C28 to C30 chain‐length constituents of the sorghum epicuticular wax.
Inventaire phytoécologique des adventices de la betterave sucrière dans le Gharb (Maroc)
Authors: TANJI A. , BOULET C. , HAMMOUMI† M. 
Published: July 2006

RésuméNous avons réalisé un inventaire phytoécologique de 122 stations sur les parcelles de betterave à sucre dans la région du Gharb (Maroc Occidental). Deux cent cinquante‐six espèces adventices ont été recensées, appartenant à quarante‐cinq familles botaniques, 80% des taxons environ étant des thérophytes, L'analyse différentielle de Czekanowski a permis de dégager quatre groupements phytosociologiques. Des groupes écologiques différentiels ont été distingués selon les caractères édapho‐climatiques (texture fine du sol, pH, calcaire total, pluviosité).
Weed interference in maize, cowpea and maize/cowpea intercrop in a subhumid tropical environment. III. Influence of land preparation
Authors: AYENI A. O. , DUKE W. B. , AKOBUNDU I. O. 
Published: July 2006

SummaryThe influence of no‐tillage and conventional tillage on the outcome of early weed interference in maize (Zea mays L., cv. TZB), cowpea [Vigna unguiculata (L.) Walp, cv. VITA‐5] and their intercrop at populations of 40000, 50 000 and 30 000 + 40 000 plants ha−1 was investigated on a loamy sand Oxic Ustropept in a subhumid tropical environment between April and July 1980. Both tillage treatments received 60 kg N, 30 kg P2O5 and 30 kg K2O ha−1. Although the weed spectrum was wider under no‐tillage, weed weight was only 52% of the weight recorded under conventional tillage 6 weeks after sowing and the average food energy yield reductions caused were 28 and 65%, respectively. Cropping pattern had no effect on plot weediness. With minimum or no weed interference, maize performance was better in conventional than no‐tillage but worse with prolonged weed interference. Cowpea responded more to weed interference than to tillage practice. Regardless of tillage practice and weed interference duration (up to 6 weeks) after sowing, maize monoculture produced the highest food energy yield, followed by maize/cowpea intercrop and cowpea monoculture in that order.
Pathogenicity of fungi and bacteria from the Sudan to water hyacinth
Authors: ABDELRAHIM A. M. , TAWFIG S. 
Published: July 2006

Summary:Studies were made in the Sudan for microorganisms pathogenic to water hyacinth (Etchhornia crassipes Solms) for biological control purposes. Many fungi and bacteria were isolated from plant parts showing disease symptoms. Pathogenicity tests revealed that only five out of the twenty‐five fungal and bacterial isolates were damaging to the weed plant. These included Acremonium zonatum, Drechslera specifera and Fusarium equiseti. Phoma sorghina and a bacterium Bacillus sp. are reported for the first time as potential pathogens of water hyacinth. Pathogenic isolates were also found to produce toxic metabolites in liquid cultures.
Pénétration, translocation et métabolisme de dinitrophénols
Authors: PONT V. , COLLET G.F. 
Published: July 2006

Résumé:Nous avons disposé de DNTBP et de DNOC uniformément marqués au 14C sur le noyau benzénique. La pénétration foliaire et racinaire, ainsi que la translocation du DNTBP sont lentes. Il a été possible de mettre en évidence, après 3 jours déjà, des composés de dégradation très éloignés des herbicides de départ. Un catabolite cinquante fois moins actif que le DNTBP a été identifié: le méthyl‐2(hydroxy‐2′dinitro‐3′5′‐phényl)‐2 propanol‐1. Sur le plan biologique, le DNTBP et le DNOC exercent un effet dèsorganisateur des membranes lipidiques. Penetration, translocation and metabolism of dinitraphenols
Influence of particle size and type of formulation on phytotoxicity and persistence of atrazine
Authors: RAHMAN A. 
Published: July 2006

Summary:The initial and residual activities of wettable powder formulations of atrazine comprising different particle sizes were investigated in field and glasshouse experiments. A flowable formulation was also compared with these. Oats were used as the test species for the glasshouse studies while in field trials effects on control of broadleaf weeds in maize were studied. No marked differences were noted in the activity of wettable powders of different particle sizes in the glasshouse as pre‐emergence applications. As a post‐emergence treatment the fine particle size was more phytotoxic than the coarse material, especially when a wetting agent was added to the spray solution. In the field trials, no appreciable differences in weed control or crop tolerance could be established regardless of the time or rate of application. The flowable formulation was less active than the wettable powders in some glasshouse experiments but no such trend was apparent in field trials. Bioassays showed that the residual activity of the flowable formulation was lower than wettable powder formulations in both glasshouse and field studies but no consistent differences were noted in the persistence of the three forms of wettable powders.
Weed interference in maize, cowpea and maize/cowpea intercrop in a subhumid tropical environment. I. Influence of cropping season
Authors: AYENI A. O. , DUKE W. B. , AKOBUNDU I. O. 
Published: July 2006

Summary:Field experiments were conducted in the early and late cropping seasons of 1979 on a loamysand Oxic Ustropept in a subhumid environment in Nigeria, using 40000, 50000 and 30000 + 40000 plants ha−1 of maize (Zea mays L. cv. TZB), cowpea (Vigna unguiculata (L.) Walp. cv. VITA‐5) and maize/cowpea intercrop respectively. These indicated that weed interference effects on crops under no‐tillage depended on cropping season, cropping pattern and crop species. In the early and late seasons respectively, thirty‐five and twenty‐nine different weed species were recorded and weed dry weights of approximately 10·4 and 5·7 t ha−1 from the plots kept weedy throughout the season reduced corresponding food energy yields by 60 and 82%. Except for the intercrop, which in the early season showed significant yield reduction when exposed to 4 weeks’ weed interference after sowing, all cropping patterns needed more than 4 weeks’ interference to show significant yield reductions, regardless of cropping season. In the early season, weed interference accounted more for the yield reductions in monocultures than it did for those in the intercrop, but in the late season all cropping patterns were equally sensitive to weed association. Maize, which performed much better in the early season, showed greater yield reductions than cowpea under early weed interference but less under full‐season interference irrespective of cropping pattern and season. Cowpea seed quality was more reduced by intercropping than by weed interference in the early season but neither of these factors affected seed quality significantly in the late season.
Soil persistence studies with bromoxynil, propanil and [14C]dicamba in herbicidal mixtures
Authors: SMITH ALLAN E. 
Published: July 2006

Summary:The persistence of bromoxynil (3,5‐dibromo‐4‐hydroxybenzonitrile), [14C]dicamba (3,6‐dichloro‐2‐methoxybenzoic‐7‐14C acid) and propanil [N‐(3,4‐dichlorophenyl)propionamide] at rates equivalent to 1 kg ha−1, were studied under laboratory conditions in a clay loam, a heavy clay and a sandy loam at 85% of field capacity and at 20±1°C, both singly and in the presence of herbicides normally applied with these chemicals as tank‐mix or split‐mix components.The degradation of bromoxynil was rapid with over 90% breakdown occurring within a week in the heavy clay and sandy‐loam soils, while in the clay‐loam approximately 80% of the bromoxynil had broken down after 7 days. In all three soils degradation was unaffected by the presence of asulam, diclofop‐methyl, flamprop‐methyl, MCPA, metribuzin or propanil.Propanil underwent rapid degradation in all soil treatments, with over 95% of the applied propanil being dissipated within 7 days. There were no noticeable effects on propanil degradation resulting from applications of asulam, barban, bromoxynil, dicamba, MCPA, MCPB, metribuzin or 2,4‐D.The breakdown of [14C]dicamba in a particular soil was unaffected by being applied alone or in the presence of diclofop‐methyl, flampropmethyl, MCPA, metribuzin, propanil or 2,4‐D. The times for 50% of the applied dicamba to be degraded were approximately 16 days in both the clay loam and sandy loam, and about 50 days in the heavy clay.
Physical basis for the maternal inheritance of triazine resistance inAmaranthus hybridus
Authors: VAUGHN K. C. 
Published: July 2006

SummaryIn an effort to determine the physical basis of the maternal inheritance of triazine resistance inAmaranthus hybridusL. the fate of plastids and other organelles in developing pollen was investigated in triazine‐resistant and susceptible biotypes. In both types, immediately after microspore mitosis, the newly formed generative cells contained an array of organelles (golgi bodies, endoplasmic reticulum, plastids and mitochondria) similar to that in the larger vegetative cells. No selective exclusion of organelles from the generative cell was noted although only small plastids were present. The immature generative cells contained small vacuoles, within which degenerate organelles were frequently observed, and no ultrastucturally recognizable plastids were found in mature cells. Maternal transmission of the triazine resistance factor thus appears to be due to a selective destruction of paternal plastids.
Herbicide injections into stumps of aspen and birch to prevent regrowth
Authors: JOHANSSON T. 
Published: July 2006

SummaryStumps of birches (Betula spp.) and aspens (Populus tremula L.) in thinning stands and on clear‐felled areas were injected with herbicides by a modified bolt gun. Herbicides were formed into tablets and placed in a wedge of nylon. The wedge was fixed in the stem with the tablet placed close to the cambium. The tablets dissolved inside the tree. Injection doses were one tablet per 2·5 or 5 cm stump diameter and were done about 5 cm below the cut surface of the stump. The injector worked adequately. Injected stumps of both species produced few and shorter suckers than untreated stumps.
Dégradation catalytique de carbamates herbicides deposés sur bentonites homoioniques. II. Cas du chlorbufame
Authors: SABADIE J. , BASTIDE J. , COSTE C M 
Published: July 2006

RásumáLa dégradation chimique en phase sèche du chlorbufame a étéétudiée après dépôt à température ambiante sur diverses bentonites homoioniques (Cu2+; Ag+). Un schéma général de dégradation a étéétabli.
Orobanche crenata (Forsk) control in Vicia faba (L.) with glyphosate as affected by herbicide rates and parasite growth stages
Authors: MESA‐GARCÍA J. , GARCÍA‐TORRES L 
Published: July 2006

SummaryThe broomrape (Orobanche crenata Forsk) susceptibility to glyphosate applied on faba‐bean (Vicia faba L.) as affected by the parasite growth stages at the time of application was studied under field conditions. Glyphosate treatments delayed O. crenata emergence. Single glyphosate application to faba‐bean infected with O. crenata predominantly at the stage (a) (small nodule) and (b) (nodules with initial vestigial roots) resulted in a moderate to low control. When the stages (c) (shoot bud already visible) or (d) (shoot and vestigial roots well developed) were the predominant stages, an excellent control was achieved with a single glyphosate application at 60 g ha−1. Increased development stages, with the shoot emerged from the shoot bud, decreased its susceptibility to glyphosate. La lutte contre Orobanche crenata en culture de férerole avec le glyphosate; influence des doses d'herbicide et du stade de développement du parasite
The survival of Alopecurus myosuroides Huds. seeds in soil
Authors: MOSS S. R. 
Published: July 2006

SummaryThe survival of Alopecurus myosuroides seeds was studied in soil under arable cropping and short term grass leys in which seed return was prevented. At two winter wheat sites, where weed seeds were sown, the mean annual seed decline was 73–83% over a 2‐ or 3‐year period. The rate of decline was similar with all the cultivation systems studied: ploughing, tine cultivation and direct drilling. Seeds buried initially by ploughing, and then not disturbed by cultivation, were slightly more persistent.At five arable sites with natural populations of A. myosuroides, seed numbers declined to an average of 3% of the original amount present after 3 years, and to 1% after 4 years. Initial populations of over 50 000 seeds m−2 were recorded. Plant populations were not always proportional to the total seed content of the soil, especially on ploughed land.Seed decline in two grass fields was similar to that under arable cropping. A. myosuroides plants were recorded in a wheat crop following a 2‐year grass ley. Weed plants did not persist in the vegetative state in grass used for conservation and grazing.At all sites, appreciable quantities of seeds were still present in the soil after 2–4 years. Although a relatively small proportion of seeds survived, the actual number of seeds surviving was substantial. For this reason, it was concluded that any eradication policy is unlikely to be effective in a cropping system dominated by winter cereals.
Soybean weed control by chloramben granules coated with haloxyfop‐methyl
Authors: DALE J. E. 
Published: July 2006

SummaryExperimental 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* (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.
Biology of Commelina benghalensis L. in south‐eastern Queensland. 2. Seed dormancy, germination and emergence
Authors: WALKER S. R. , EVENSON J. P. 
Published: July 2006

SummaryGermination of freshly harvested seeds of Commelina benghalensis L. varied from 0–3% for small aerial seeds, 20–35% for large aerial seeds and from 33% for small underground seeds to 90% for large underground seeds. Innate dormancy of all seed types was completely overcome by clipping the seed coat. Exposure to 90°C dry heat for 2 h was also effective in increasing germination of the three strongly dormant seed types.Optimum temperature for germination varied with the different seed types. Periods of likely major weed infestation from the four seed types were predicted using soil temperature data. Exposure to light increased germination but was not essential and underground seeds responded more to light than aerial seeds. Optimum depth of emergence for the four seed types was from 0 to 50 mm and there was a positive correlation between maximum depth of emergence and seed weight.
Rapid chlorophyll fluorescence technique for the study of penetration of photosynthetically active herbicides into leaf tissue
Authors: HABASH D. , PERCIVAL M. P. , BAKER N. R. 
Published: July 2006

SummaryA rapid and sensitive technique, involving analysis of chlorophyll a fluorescence induction kinetics, for the study of the penetration of photosynthetically active herbicides into leaves is described. A range of chlorophyll fluorescence parameters are examined for wheat leaves treated with diuron in order to determine the most appropriate parameter to use in herbicide penetration studies. The usefulness of the technique is demonstrated by examination of the effect of a range of commercially available additives on diuron penetration in wheat leaves.
Nitrogen, phosphorus and potassium effects on the incidence of Striga asiatica (L.) Kuntze in maize
Authors: FARINA M. P. W. , THOMAS P. E. L. , CHANNON P. 
Published: July 2006

SummaryThis work was conducted in an attempt to elucidate some of the effects of nutrition on the incidence of witchweed (Striga asiatica (L.) Kuntze) in maize (Zeu mays L.).In an N, P, K field trial N applications resulted in up to 93% reduction in the incidence of witchweed. Maize height was unaffected by N and decreases in the incidence of Striga could not be attributed to the effects of host‐parasite competition. Although plant height was 10% lower on zero‐P plots, P did not have a significant effect on Striga and the beneficial effects of N were equally evident on both high and low‐P plots.Potassium applications had the opposite effect to N. While the main effect of K was not quite significant at the 5% level of probability, an N × K interaction was evident, and in the absence of applied N, K applications led to a more than 4‐fold increase in the incidence of Striga. As with N, K did not influence plant height and it seems unlikely that competition effects were responsible.