bluuebunny/crossref_metadata_2025_split huggingface dataset:
Aspects of the selective phytotoxicity of methazole. I. Measurements of species response, spray retention and leaf surface characteristics
Authors: VERITY JULIE , WALKER ALLAN , DRENNAN DONALD S. H. 
Published: July 2006

Summary:The responses of onion (Allium cepa). Veronica persica, Matricaria matricarioides and Stellaria media to post‐emergence applications of methazole were measured in field and glasshouse experiments. Stellaria media was the most susceptible species and V. persica the least. Plants of all species became more tolerant the larger they were at the time of treatment, and this was most pronounced in onion. Onion generally retained less spray per unit of dry weight than the other three species and retention was less on old compared with young plants, whereas with the weed species, this did not change appreciably with age. There was a progressive increase in the amount of structured crystalline wax on successive onion leaves which resulted in larger contact angles between droplets and the leaf surfaces and lower spray retention per unit of dry weight. There was less wax development on the leaf surfaces, increased spray retention, and increased susceptibility to methazole in onion treated pre‐emergence with ethofumesate thus confirming that these factors are interrelated. While the increased tolerance of onion to methazole with age could be explained in part by decreased retention of herbicide, this was not so for the weed species, and other factors must determine their change in tolerance with age.
Chemical weed control in rainfed cowpea (Vigna unguiculata (L.) Walp) in the Guinea savanna zone of Nigeria
Authors: LAGOKE S. T. O. , CHOUDHARYAND A. H. , CHANDRA‐SINGH D. J. 
Published: July 2006

SummaryIn a field trial in 1978 at Mokwa, southern Guinea savanna zone of Nigeria, metolachlor at 1.5 and 3.0, prometryne at 2.0 and norflurazon and diuron at 1.6 kg/ha combined good weed control with high grain yield of cowpeas. The grain yields with these herbicides were comparable to those of the hoe‐weeded and significantly higher than the weedy controls. In 1979, under wetter conditions, crop injury was observed with prometryne and linuron at 2.0 kg/ha. However, the grain yields obtained with alachlor, metolachlor, chloramben, pendimethalin and norflurazon and their mixtures with prometryne, linuron, diuron or metobromuron were comparable to that of the hoe‐weeded treatment. In 1979 at Samaru, northern Guinea savanna, pendimethalin at 1.5, metolachlor at 3.0 and chlorbromuron and linuron at 1.0 kg/ha gave selective weed control. Prometryne at 2.0 kg/ha was the only herbicide that gave a significantly lower broad‐leaved weed weight than the weedy check but it reduced the crop stand. At 1.0 kg/ha it was tolerated by the crop but failed to control grasses. Metolachlor at 1.5 kg/ha had a significantly higher broad‐leaved weed weight than the weedy check. All theherbicides, except pendimethalin at 3.0 kg/ha, controlled the annual sedges at Samaru.
Studies on the chemical control of blackgrass (Alopecurus myosuroides Huds.) in winter wheat in the West Midlands
Authors: SCOUREY L. R. K. , YOUNG I. , PAGE J. B. 
Published: July 2006

SummaryIn trials carried out in 1978–80, blackgrass populations in winter wheat growing on heavy soil were substantially reduced by all chemical treatments tested, the least effective being methabenzthiazuron. Wild oat populations were also reduced by all treatments except chlofop‐isobutyl and methabenzthiazuron. On average of the 3 years only metoxuron treatment gave wheat yields significantly higher than the unsprayed crop.
Comparative studies of safeners for the prevention of EPTC injury in maize
Authors: GöRöG K. , MUSCHINEK GY. , MUSTÁRDY L. A. , FALUDI‐DÁNIEL Á. 
Published: July 2006

SummaryThe herbicide safener N‐dichloroacetyl‐1‐oxa‐4‐aza‐spiro‐4,5‐decane (AD‐67) is of similar efficiency as the extensively used N.N‐diallyl‐2,2‐dichloroacetamide (R‐25788) and the structurally related 3‐(dichloroacetyl)‐2,2‐dimethyl‐1,3‐oxa‐zolidine (AD‐2) in reducing EPTC [S‐ethyl‐N,N‐dipropyl (thiocarhamate)] injury to maize (Zea mays L. cv. KSC 360). EPTC treatment produces growth retardation and deformities and inhibits CO2 fixation. It does not reduce epicuticular lipids appreciably but affects wax arrangement on the leaf surface. When EPTC is applied together with one of these safeners, these injuries are not observed. All three safeners act similarly. Each prevents the herbicide‐induced aggregation of epicuticular wax of maize, thereby protecting the plants against the formation of areas where the underlying cuticle layers are exposed and increase in transpiration.
Seed production by an arable weed community
Authors: LEGUIZAMÓN E. S. , ROBERTS H. A. 
Published: July 2006

SummaryAfter cultivation in early April of a sandy loam soil with 9500 apparently viable seeds/m2 in 0–10 cm, 295 seedlings/m2 emerged of which about half survived to maturity in July. Seeds were dispersed from mid‐June to November and 136,460/m2 were returned to the soil, representing a 14‐fold increase in the seed bank. Application of soil‐acting herbicides reduced the numbers of weeds and the total seed output, but that of tolerant species was increased. Maximum numbers of seeds were 59,980/m2 for Chenopodium album, 39,430/m2 for Sleltaria media and 37,580/m2 for Veronica persica.
The effects of soil texture and moisture on reproductive strategies of Spergula arvensis L. and Plantago major L.
Authors: TRIVEDI SUDHIR , TRIPATHI R. S. 
Published: July 2006

SummaryThe reproductive strategies of two weeds, Spergula arvensis L. and Plantago major L., were studied in relation to soil texture and moisture regime. On sandy soil, daily watering gave greatest dry wt per plant in S. arivensis, while fortnightly watering gave the greatest in P. major. In P. major, seed production was increased with increased moisture stress in sandy soil, but not in garden soil when watered fortnightly. Conversely, S. arvensis showed a decrease in seed number with increasing moisture stress in both soil types. The reproductive effort of S. arvensis was much greater (26.2–63.1%) than P. major (2.3–9.2%). There was greater emphasis on reproduction by S. arvensis under both soil types and various moisture regimes while P. major was characterized by higher allocation to vegetative structures which may confer a competitive advantage by increasing its efficiency of resource capture. Thus, S. arvensis seems to be r‐selected and P. major K‐selected. The differences in the reproductive strategies of the two weeds are discussed with reference to the environmental conditions under which they grow in nature.
A study on seed population dynamics of three weedy species of Eupatorium
Authors: YADAV A.S. , TRIPATHI R.S. 
Published: July 2006

SummaryThe data on seed population dynamics of three weedy species of Eupatorium, viz. E. adenophwrum Spreng., E. riparium Regel and E. odoratum L. have been presented and discussed in the paper. The seed production and seed populations in soil seed bank were estimated, and the fate of buried seeds in soil was followed over a 2‐year period. All the three species of Eupatorium produced a large number of seeds. The seed production of E. riparium per unit area was higher than that of the other two species because of its high population density. In all the three species most of the seeds were found to be present in the top 2 cm of the soil. The viable seed population of the three species of Eupatorium declined exponentially alter their burial in soil showing almost similar mortality patterns. A large proportion of seeds of all the Eupatorium spp. remained under enforced dormancy during their burial in soil with only a small fraction exhibiting induced dormancy. The longevity of the buried seeds increased on account of the dormancy imposed on them. The loss of seeds through degeneration and/or decomposition was rather low.
Population dynamics of Eupatorium adenophorum Spreng. during secondary succession after slash and burn agriculture (jhum) in north eastern India
Authors: KAMAKRISHNAN P.S. , MISHRA B. K. 
Published: July 2006

Summary Eupatorium adenophorum Spreng. is an important weedy colonizer in early successional communities developing after slash and burn agriculture (jhum) at higher elevations of the north‐eastern hill regions of India. The relative performance of this species in terms of fecundity and survivorship in successional plant communities has been worked out. A net population increase occurred through both vegetative and sexual reproduction in early successional fallows up to 6 years old, the increase being greatest in a 6‐year fallow. Mortality of seedlings was high in 1‐ and 3‐year fallows, low in a 6‐year fallow but reached 100% in older fallows. Seedling mortality was maximal during the monsoon although some seedlings also died during winter as a result of drought and frost. Mortality of vegetative sprouts followed a similar pattern to that of seedlings. The reproductive potential was reduced with increasing age of the successional communities and in a 15‐year fallow all individuals were non‐reproductive. Since E. adenophorum is able to succeed only in fallows of less than 6 years, repeated short jhum cycles of 4–5 years have had the effect of arresting succession al the weedy stage.
Growth and chemical composition of soybeans as affected by trifluralin and soil salinity
Authors: MAFTOUN M. , BASSIRI A. , SAMENI A. M. , YASREBI J. 
Published: July 2006

SummaryThe combined effects of 0, 1 and 2 ppm trifluralin and five soil salinity levels (0.35, 2, 4, 6 and 8 mS/cm) on growth and chemical composition of soybeans [Glycine max (L.) Merr.] were studied in a glasshouse experiment. Analyses of variance indicated that the interaction of soil salinity and trifluralin was not significant for root and top dry weights and root nodulation. Root dry weight was not affected by trifluralin, whereas 2 ppm trifluralin significantly reduced top dry yield and root nodulation. Shoot and root yields and root nodulation were reduced with increasing soil salinity.Trifluralin at 1 ppm significantly decreased P concentration and at 2 ppm substantially increased N concentration. Moreover, there was a general trend of an increase in N concentration and a decrease in P concentration with salinity.The concentration and uptake of Cl and Na increased with increasing soil salinity. Probably large accumulations of Cl and Na and/or water stress caused by high salinity were responsible for growth reductions in salinized media.
Control of problem weeds of maize on the Transvaal Highveld (South Africa). II. Datura stramonium L.
Authors: MALAN C. , VISSER J.H. , GROBBELAAR N. 
Published: July 2006

SummaryAs was described in a previous publication, the influence of a number og herbicides and herbicide mixtures which are being used for the post‐emergence control of weeds in maize on the Transvaal Highveld, have been tested for their efficiency in the control of problem weeds. Both the percentage mortality and percentage dry mass difference between the test plants and the controls 10 days after application of the respective herbicides were used as bioassay methods. Datura stramonium L. was very susceptible to most of the herbicidal treatments up to the nine‐leaf stage. The reason why it is considered a problem weed should perhaps be sought in the erratic germination of its seeds over a number of years, thus evading common practices of weed control.
Growth and reproduction of Cyperus esculentus L. and Cyperus rotundus L.
Authors: WILLIAMS ROBERT D. 
Published: July 2006

SummaryThe growth of both species (as characterized by their total dry weight, inflorescence dry weight, root and rhizome dry weight and number of shoots per pot) was similar, but they differed in the manner in which the dry weight was partitioned to reproductive structures. Each species partitioned less than 2% of its dry weight into floral formation. However, yellow nutsedge (Cyperus esculentus L.) partitioned only 28% of its dry weight to tubers, whereas purple nutsedge (C. rotundus L.) partitioned 50% of its dry weight to fewer and larger tubers. The allocation of dry weight to reproductive structures was related to changes in day‐length. Yellow nutsedge tuber formation increased as day‐length decreased from 14.5 to 12.5 h, while floral formation did not begin until the day‐length dropped below 14 h. Purple nutsedge formed inflorescences earlier and production continued throughout the remainder of the study, but tuber formation was curvilinear and accelerated as the day‐length decreased.
Factors affecting weed seed germination and seedling growth in lowland rice in Indonesia
Authors: PONS T. L. 
Published: July 2006

SummaryExperiments were carried out in Indonesia to see whether weeds of lowland rice fields could be managed by manipulation of the water table and what factors affected germination of their seeds. It was found that seeds of two Scirpus spp. germinated when buried in anaerobic soil but not when on the surface, whereas seeds of two Echinochloa spp. germinated when on the surface of both aerobic and anaerobic soils but when buried germinated only in aerobic soil.The germination of weed seeds was affected to differing extents by submergence in water at depths down to 20 cm. Germination of Fimbristylis littoralis seeds was greatly reduced and of Ludwigia hyssopifolia was complétély inhibited by submergence. Conversely, germination of Monochoria vaginalis seeds was virtually unaffected. It is suggested that the effect of submergence on germination of some species may be due to their reaction to the amplitude of temperature fluctuation. The germination and emergence of seedlings under water were greatly reduced by a cover of Salvinia molesta. The practical importance of these findings is discussed.
Collaborative studies of dose‐response curves obtained with different bioassay methods for soil‐applied herbicides
Authors: NYFFELER A. , GERBER H.‐R. , HURLE K. , PESTEMER W. , SCHMIDT R. R. 
Published: July 2006

SummaryIn a collaborative study by 12 laboratories the reproducibility of bioassay techniques was analysed by comparison and statistical treatment of the ED50‐values (μg herbicide/g soil). Commonlyused bioassay techniques were investigated; two direct seeding methods, a transplanting method and a shoot extension method. The herbicides studied were two photosynthesis inhibitors, atrazine and metribuzin using Lepidium sativum and Brassica rapa as test plants; two germination inhibitors, tri‐allate and trifluralin using Avena sativa as test plant. The mean ED50‐value of atrazine in the direct seeding method was 0.18 with a variation from 0.12 to 0.29 and 0.12 (0.07–0.68) in the transplanting method. The values of metribuzin were 0.05 (0.02–0.11) and 0.03 (0.01–0.15) respectively. The values for triallate were 1.15 (0.50–2.60) in the direct seeding method and 1.10 (0.54–2.53) in the shoot extension method and for trifluralin 3.11 (0.72–18.31) and 1.33 (0.48–2.94) respectively. The reproducibility was best in the shoot extension method. No outliers (confidence intervals lying entirely outside the confidence interval of the overall mean) in the ED50‐values were observed with atrazine and metribuzin when using the direct seeding method, whereas with the germination inhibitors a high number of results (four with tri‐allate, six with trifluralin) could be considered as outliers. A comparison of the use of fresh weight and dry matter showed good agreement between the ED50‐values they gave, with similar reproducibility.
The role of waxes in the uptake of metolachlor into sorghum in relation to the protectant CGA 43089
Authors: EBERT E. 
Published: July 2006

SummaryThe grass weed herbicide metolachlor (2‐chloro‐N‐[2‐ethyl‐6‐methylphenyl]‐N‐[2‐methoxy‐1‐methylethyl]acetamide) which is especially effective against wild millets, inhibits the formation of epicuticular waxes on sorghum leaves. The metolachlor protectant CGA 43089 [α ‐ (cyanomethoximino) ‐ benzacetonitrile] prevents the depletion of the waxes on the leaves of metolachlor‐treated sorghum plants, as demonstrated by scanning electron microscopy. This alteration of the plant surface polymers also changes their permeability to the herbicide. 14C‐metolachlor uptake into isolated coleoptiles and first leaves of sorghum which had been pretreated with the herbicide was increased. Incubation with added protectant reduced the uptake of 14C‐metolachlor. It is postulated that the modifications caused by metolachlor and its protectant to sorghum surface structures influence the action of the herbicide in two ways:

The selectivity observed against sorghum and millet grasses could occur because of an increased uptake of metolachlor through cuticles which are particularly sensitive to the structural changes caused by the herbicide, since the composition of the plant waxes is very species‐specific.
The loss of cuticular integrity is prevented by the protectant CGA 43089, which greatly reduces penetration of metolachlor.
Trifluralin persistence under two different soil and climatic conditions
Authors: SOLBAKKEN E. , HOLE H. , LODE* O. , PEDERSEN T.A. 
Published: July 2006

SummaryAn investigation of the persistence of trifluralin was conducted as field experiments over a two year period at latitudes 60°N and 70°N respectively, paying special attention to the soil and climatic conditions. These experiments included glasshouse bioassays with Lolium multiflorum. gas‐chromatographic residue analyses and qualitative and quantitative studies on soil bacteria. Special attention was devoted to clay minerals as well as to the soil organic matter. 100 g or 500 g of trifluralin a.i. ha−1 were applied in the spring 1978 with a reapplication on half of the area the following spring (1979).The phytotoxicity of trifluralin appeared more severe on re‐treated plots compared with single applications even at approximately equal residue levels. Trifluralin did not seem to have any real influence on the total number of soil bacteria. A qualitative change of the bacterial flora was however observed as a relative increase of non‐sporeformers, Gram negatives and Actinomy‐cetes and a relative depression of the Coryneform bacteria/Arthrobacter group.Even at a recommended dosage, a carry‐over phytotoxicity the following year may occur, especially when the content of organic matter in the soil is low. Care should therefore be taken when using this herbicide on the same field in two successive years. The properties of the soil seemed to exert a greater influence than the climatic factors on the persistence of trifluralin.
Fate of glyphosate in Agropyron repens (L.) Beauv. growing under low temperature conditions
Authors: DEVINE M. D. , BANDEEN J. D. 
Published: July 2006

SummaryAbsorption, translocation and distribution of 14C‐glyphosate were examined in Agropyron repens (L.) Beauv. plants growing under field conditions in the autumn. Glyphosate absorption did not increase beyond 3 days after application, whereas translocation to the rhizomes continued up to 7 days after application. The translocated glyphosate accumulated more in new rhizomes than in older parts of the rhizomes. Ten per cent of the glyphosate translocated out of the treated shoot was recovered in younger shoots 7 days after application. Plants harvested the following spring contained less than 20% of the glyphosate originally applied. Although a growth cabinet experiment indicated that 34% of the glyphosate in the rhizomes of treated plants could be remobi‐lized into new aerial shoots, considerably less was recovered in new, aerial shoots in the spring in the field‐grown plants. Freezing experiments showed that glyphosate translocation to the rhizomes was only prevented when cold treatment caused visible damage to A. repens foliage.
Action of chlorfenprop‐methyl on membrane integrity in plant mitochondria
Authors: GAUVRIT C. 
Published: July 2006

SummaryThe action of chlorfenprop‐methyl, chlorfenprop and its cysteine conjugate was studied on potato tuber mitochondria. Chlorfenprop‐methyl altered membrane structure at 250 μM. leading to a loss of membrane integrity. Chlorfenprop and its cysteine conjugate were without any significant effects. From what is known about the rapid hydrolysis of chlorfenprop‐methyl in plant tissues and from the results presented in this paper, it was deduced that alteration in intra‐cellular membrane integrity is not a mechanism of phytotoxic action for chlorfenprop‐methyl.
Interference between velvetleaf (Abutilon theophrasti Medic.) and soybean (Glycine max (L.) Merr.) I. Growth
Authors: DEKKER J. , MEGGITT† W. F. 
Published: July 2006

SummaryThree field experiments were conduced to evaluate the effect of Abutilon theophrasti on dry matter, branching and flowering node, and seed production of soybean. Low populations (2.4–4.7 plants m−2) of the weed reduced soybean dry matter, flowering node and seed production. The effect was most pronounced on soybean seed yield, and less on flowering node and dry weight production. These effects were due to the presence of A. theophrasti with soybean, and not to changes in plant population. The effect on soybean branching node production was inconsistent between years.
Evolution de l'aptitude à germer des graines d'Amaranthus retroflexus L. récoltées dans différentes conditions, au cours de leur conservation
Authors: CHADOEUF‐HANNEL RÉGINE , INRA G. BARRALIS 
Published: July 2006

RésuméDans cette expérimentation est étudié l'effet de la conservation au sec à 20 ± 1°C pendant 6 mois ou dans le sol à 15 cm de la surface pendant un hiver, sur le comportement germinatif des graines d'Amaranthus retroftexus L. récoltées au niveau de l'inflorescence principale sur des plantes portegraines cultivées dans les conditions naturelles ou dans différentes conditions contrôlées de photopériode ou de température. A la récolte, les graines prélevées sur des plantes qui se sout développées tard (juillet) dans les conditions naturelles sont moins dormantes que celles prélevées sur des plantes apparues plus tôt (avril); en conditions eontrôlées, les plantes cultivées à 20°C en jours longs de 16 h donnent des graines plus dormantes que celles récoltées sur des plantes cultivées soit à 20°C en jours courts de 8 h, soit à 25°C en jours longs de 16 h. Après conservation au sec ou dans le sol, cette hétérogénéïté de l'aptitude à germer s'atténue mais n'est jamais totalement supprimée: les graines conservent les caractéristiques acquises lors de leur formation et de leur maturation. A la récolte, pour une condition de culture définie, la dormance des graines produites dépend de l'état physiologique des plantes porte‐graines; après conservation, les graines qui étaient les plus dormantes à la récolte germent mieux que les graines les moins dormantes. Enfin, l'enfouissement a un effet plus favorable sur la levée de dormance des graines que la conservation au sec.