bluuebunny/crossref_metadata_2025 huggingface dataset:
Cinétique de dégradation chimique du propyzamide (Kerb) en milieu aqueux I. Influence du pH et d'oligo‐éléments
Authors: BASTIDE JEAN , COSTE CAMILLE
Published: July 2006

Kinetics of chemical degradation of propyzamide (Kerb) in aquatic environments—influence of pH and trace elements

Degradation of propyzamide in aquatic environments has been studied with particular reference to pH and the presence of trace elements. The degradation is quicker in alkaime than in acid surroundings but this is appreciable only in acidic and strongly alkaline media. Iron and copper salts had little influence but, on the contrary, silver salts had a strong effect. The mechanism of this interaction is discussed.
Control of Echium plantagineum L.with 2, 4‐D and grazing management
Authors: PIGGIN C. M.
Published: July 2006

This paper describes a field experiment conducted in north‐east Victoria investigating the control of Echium plantagineum L. in a pasture with 2, 4–D and grazing management.

Spraying with a small dose of 2, 4‐D (0–14 kg a.i./ha) in late autumn/early winter, followed about 2 weeks later by heavy grazing, removed E. plantagineum from the pasture, whilst the associated pasture species, Trifoliutn subierraneum L., was retained. Continuous grazing without spraying also resulted in good control of E. plantagineum.

Herbage production of the pasture in winter was, however, reduced by spraying. The reasons underlying these observations, and farm management programmes for the longterm control of E. plantagineum, are discussed.
Studies on the mechanism of herbicidal action of N‐(Phosphonomethyl) glycine*
Authors: EKANAYAKE A. , WICKREMASINGHE R. L. , LIYANAGE H. D. S.
Published: July 2006

Application of N‐(phosphonomethyl) glycine or GLY'PHO‐SATE to couch grass Pancum repens (L) Beauv. resulted in an intitial increase of the total amino acid content in the plant. which reached a maximum on the 8th day following treatment This was most marked in the rhizomes where the value was about three times that of the control plants. The initial increase fell off rapidly with time and on the 15th day after application the total amino acid content of the treated leaf and rhizome samples was less than the controls Resurgence of rhizome activity was noticeable on about the 48th day (viz. 7 weeks after t he Ist application).
Inhibition of seedling growth by wild myrtle (Myrtus communis L.)
Authors: KHOSH‐KHUI M. , BASSIRI A.
Published: July 2006

Plants of wild myrtle (Myrtus communis L.) collected at full bloom contained substances inhibitory to the germination and seedling growth of perennial ryegrass. (Lolium perenne L. cv Hollandi)

Tissue suspensions had a greater inhibitory activity than water extracts of the plant tissue. Boiling the plant material also increased the inhibitory activity of suspensions and extracts. Flower, and buds, fruit covers and leaves had the greatest inhibitory effect/unit weight ot tissue but inhibitory activity was also present in stems and roots at lower concentrations.

The effect of myrtle leaf suspensions on germination of seed of thirteen common garden flowers was also examined: Germination of Petunia. Antirrhinum, Liaum. Cheiranthus and Lathyrus was inhibited completely or substantially depressed. Germination of Zinnia, Tagrtes. Verbena and Dianthus was not much affected, while that of Brllis. Gaillardia. and Viola was affected to an intermediate extent.

These results suggest that the possible use of wild myrtle as an evergreen hedge plant needs to be examined further because of possible interference with the growth of nearby lawns and flowers.
Influence of R‐40244 on pigment content of wheat and corn
Authors: DEVLIN R. M. , KISIEL MARIAN J. , KOSTUSIAK ANDRZEJ S.
Published: July 2006

Chlorophyll production by wheat (Triticum aestivum L. ‘Mericopa’) and corn (Zea mays L. Merit) was severely curtailed by the experimental herbicide l‐(m‐trifluoromethylphenyl)‐3‐chloro‐4‐chloromethyl‐2‐pyrrolidone (R‐40244). A 96% loss in chlorophyll content was observed in wheat seedlings treated with 320 μmol/1 R‐40244. In corn 320 μmol/1 R‐40244 caused a 40% drop in chlorophyll content. Carotenoid production in both wheat and corn was inhibited by R‐40244, 320 μmol/1 of the herbicide causing a 97% reduction in wheat and a 44% reduction in corn. The inhibition of carotenoid production which, in turn, allows chlorophyll to be photooxidized, may represent the mode of action of R‐40244. Hill reaction activity was not detected for R‐40244.
The significance of noxious weeds on roadsides in agricultural areas of Victoria, Australia
Authors: LANEA D.
Published: July 2006

The occurrence of noxious weed species on roadsides and adjacent farmland was studied in ten agricultural areas throughout Victoria. Australia. The presence of noxious weeds in both situations was influenced by the other vegetation present and was reduced by tree cover on roadsides or improved pastures on the farmlands. Most of the noxious species recorded were found both on the roadsides and on farmland. The shrubs (e.g. Acacia armata R. Br., Crataegus monogyna N.J. Jacq., Genista linifolia L. and Lycium ferocisinnum Miers) were more abundant on roadsides, and usually occurred only as hedges on farmland. Hypericum perforatum L. was recorded only on roadsides since this species is now generally controlled in farmland by pasture improvemenl.

Because noxious weeds did not appear to invade better managed farmland the significance of their control on roadsides should be reassessed. Where control on roadsides is considered to he necessary, better suppression should be achieved by maintaining good tree and grass cover.
Soil persistence experiments with [14C]2,4‐D in herbicidal mixtures, and field persistence studies with tri‐allate and trifluralin both singly and combined
Authors: SMITH ALLAN E.
Published: July 2006

The persistence of [14C]2,4‐D at a rate equivalent to 1 kg/ha was studied in the laboratory on a heavy clay and a sandy loam at 85%of field capacity and 20°C both alone and in the presence of 1 kg/ha dicamba, dichlorprop, difenzoquat, TCA, and 2,4,5‐T. The persistence of 2,4,5‐T was also monitored in both soils under the same conditions in the presence and absence of [14C]2,4‐D. All soils were extracted at weekly intervals using aqueous acidic acetonitrile and analysed for [14C]2,4‐D remainining radiochemical techniques. The extracts containing 2,4.5‐T were additionally analysed gas chromatographically for that herbicide.

In each soil type the half‐life of the 2,4‐D was similar regardless of whether applied singly or in combination with the five herbicides tested. Similarly, [14C]2,4‐D did not affect the breakdown of 2,4,5‐T in either soil type.

The persistence of tri‐allate (1·5 kg/ha) and trifluralin (0·75 kg/ha) both singly and in combination were compared using small field plots at two locations in Saskatchewan. Applications were made during May of 1977 and 1978 and the plots were sampled and analysed for herbicide(s) remaining after 10 and 20 weeks, respectively. The results indicate that within experimental error the loss of both tri‐allate and trifluralin from the plots treated with the mixture was the same as from plots treated with the individual compounds.
Annual weed competition in wheat crops: the effect of weed density and applied nitrogen
Authors: WELLS G. J.
Published: July 2006

Experiments investigating the effect of weed density on the yjeld of a wheat crop at three levels of applied nitrogen were conducted in north‐western Victoria. Australia, during 1970. There were five sites, each infested with a pure stand of one of the following annual broad‐leaved weed species: Lithospermum arvense, Brassica tournifortii. Lamium amplt'xicaule, Amsinckia hispida and Fumaria parviflora. At the three‐leaf stage of crop growth, the weed populations were systematically thinned with a specially developed spray boon) (which is described) to give a range of weed densities in competition) with the crop.

The relalionship between dry matter production and population density for all but one weed species was curvilinear, but the degree of curvature was small and competition in the wheat crop was linear for four of the five weed species. There were large differences in the competitive ability of individual weed species and these have been described by regression equations. Applied nitrogen increased wheat yields at all sites but weed competition was not affected.

The use of these grain yield‐weed density relationships in predicting crop losses from weed competition is discussed.
Effect of soil water content at the time of application on herbicide content in soil solution extracted in a pressure membrane apparatus
Authors: HANCE R. J. , EMBLING S. J.
Published: July 2006

Wettable powder formulations of simazine, metribuzin and linuron and a suspension concentrate of simazine were sprayed on to soil particles which were either at a water content equivalent to pF 2·5 or air dry. Air dry samples were then wetted to pF 2·5 immediately or after 24 h. Soil solutions were removed using a pressure membrane apparatus at intervals up to 96 h after wetting. In each case the concentration in soil solutions expressed after 96 h following application to wet soil, or dry soil wetted immediately, were close to those predicted on the basis of Freundlich adsorption isotherm data obtained in slurry equilibrium conditions. There were, however, some differences after shorter periods.

Concentrations were always lower in solutions obtained from air dry soil that was not wetted for 24 h. After 96 h simazine and metribuzin concentrations were about 50% of those obtained following application to wet soil, while that of linuron was about 25%. Differences of this size may be large enough to affect mass transfer phenomena and phytotoxicity. It seems likely that suspension of these herbicides sprayed in formulations on to wet soil dissolved in soil water at least as fast as would be predicted theoretically.
Ultrastructural effects of formulated picloram on leaflets of velvet mesquite and catclaw acacia*
Authors: BLECKMAN C. A. , HULL H. M. , MORTON H. L.
Published: July 2006

The effects of picloram formulated with a nonionic surfactant (X‐77) and of the surfactant alone on the ultrastructure of leaf cells of velvet mesquite (Prosopis velutina Woot.) and catclaw [Acacia greggii var. ariznica (Gray) Isely] were examined The surfactant induced temporary protrusions from chloroplasts in both species. A proliferation of rough endoplasmic reticulum (RER) was noted in velvet mesquite within 8h of application of the herbicide and in catclaw with in 27 h. By 72h after treatment. both species exhibited distortions of organelles with more severe symptoms in catclaw. the species more sensitive to the herbicide Leaf abscission occurred subsequently and was more pronounced in catclaw than in mesquitel It is known that RER proliferation is induced by ethylene and that ethylene evolution is stimulated by picloram. The present study suggests that the interaction between these two chemicals was similar in the two plant species studied.
Effect of herbicides on cell membrane permeabUity in Lemna minor
Authors: O'BRIEN MARY C. , PRENDEVILLE G. N.
Published: July 2006

Leakage of electrolytes was the criterion used to study the effects of several herbicides on cell membrane permeability in Lemna minor L. Dinoseb. sodium azide, linuron, prometryne and simazine were the most active in increasing cell membrane permeability, followed by oxyfluorfen, amitrole, and 2,4—D. Glyphosate and dalapon were the least active. In all cases, the longer the period elapsed after treatment (i.e. 96 h) the lower was the concentration needed to alter cell membrane permeability. Light was necessary for oxyfluorfen activity. With glyphosate, dalapon and oxyfluorfen, visible injury symptoms were noted after 48–96 h, but no further significant increase in cell membrane permeability occurred as a result.
Selectivity of glyphosate in creeping red fescue and reed canarygrass*
Authors: MAROUIS L. Y. , COMES R.D. , YANG C. P.
Published: July 2006

The differential tolerance of resislant creeping red fescue (Fes‐ tuca rubra L, var, rutra) and susceptibie reed canarygrass (Pha‐ laris arundinacea L.) seedlings to glyphosate [N‐(phosphono‐ meihyDglycine) was confirmed under growth chamber condilions. The absorption, transiocation and metabolism of 14C‐glyphosate was examined in both species to determine if differences in these processes could account for the observed selectivity, Creepmg red fescue actually absorbed more glyphosate than did t‐eed canarygrass, and both species rapidly translocated the herbicide throughout their respective tissues. No metabolism of glyphosate was detected in either species. Differential interception and retention of the glyphosate spray can probably be eliminated as possible selectivity mechanisms. The relative tolerance of creeping red fescue to glyphosale appears to be related to its ability lo regenerate roots and shoots from the crown of the plant, but the mechanism of resistance remains obscure.
Studies of Salvia reflexa Hornem. I. Possible competitive mechanisms
Authors: LOVETT J. V. , LYNCH J. A.
Published: July 2006

When grown in mixtures with equal numbers of wheat plants Satvia reflexa was found not to be a strong competitor. The height and inflorescence dry weight of wheat was increased by watering the mixtures from above ihe foliage. These effects were accentuated by moisture stress. Aqueous leachatcs oi S. refiexa foliage were found (o inhibit the germination and/or early growth of wheat grown on filter paper in petri dishes and in different soil lypes.
Physiological effects of buthidazole on Zea mays L., Amaratithus retroflexus L., Medicago sativa L. and Agropyron repens(L.) Beauv.*
Authors: HATZIOS KRITON K. , PENNER DONALD
Published: July 2006

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.
The effects of topical applications of glyphosate and aminotriazole on volunteer potatoes (Solanum tuberosum)
Authors: LUTMAN P. J. W.
Published: July 2006

Application of small amounts of glyphosate and aminotriazole to the top 2–3 leaves of potato stems killed those stems. Untreated stems attached to the same plant did not die, although they showed symptoms of herbicide damage. Glyphosate caused the death of the apices of the untreated stems, growth of axillary buds and sometimes aerial tuberization. Concentrations of glyphosate between 025 and 8% a.i. and of aminotriazole between 1 and 4% a.i. achieved equally good control of treated stems, although the higher concentrations worked more quickly and generally resulted in more symptoms on the untreated stems. The more stems that were treated on a particular plant, the greater the symptoms on the untreated ones. When all the stems were treated, no healthy tubers were produced; when only some were treated, both healthy and deformed tubers were found at harvest. The effects on the untreated stems are examined in relation to the translocation of glyphosate and the anatomy of the potato plant.
The effect of chlorffenprop‐methyl on 32P uptake, transport and metabolism in Avena fatua L. and Hordeum vulgare L.
Authors: BERGMANNOVÁ EVA , TAIMR L.
Published: July 2006

The eflect of chlorfenprop‐methyl on plant weight, root uptake, transport and metabolism of 32P in wild oat and barley plants was examined 4 h. 1, 3 and 9 days after treatment. The fresh weight of treated wild oat plants became significantly less than that of the controls by day 9. There was no significant effect on the weight of barley plants during this period.

Uptake of 32P by treated wild oat planus progressively decreased during the experiment and by day 9 was significantly 70% less yhan that in the control: uptake by barley plants showed a significant 30% increase by day 9. Transport of 32P to the shoots followed a similar pattern. In wild oat plants, transport was significantly inhibited at all sampling dales by 44–91%. In barley plants. 32P transport to the shoots tended to be enhanced by day 9 after herbicide treatment.

Metabolism of 32P in wild oat plants was affected 4 h after treatment. The content of 32‐P in individual fractions (inorganic, organic, lipidic, and nucleic acid P) was lower in treated plants, especially in the shools. In barley plants. 32P incorporation into the individual fractions was initially inhibited 4 h after treatment, but later corresponded to that found in the control.
Chemical control of Eleusine indica and other weeds in Setaria anceps
Authors: HAWTON D.
Published: July 2006

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
Inducing a possible state of senescence in developing barley seedlings by applying the α‐chloroacetamide propachlor
Authors: KLEUDGEN HANS KARL
Published: July 2006

Propachlor (5, 50, 500 M) applied to the roots of barley (Hordeum vulgare L.) seedlings after 7 and 10 days, respectively, induces decreasing accumulation of fresh matter and dry matter; shoot length and root length are reduced. There was observed higher Hill activity, but lower O2‐evolution per unit dry weight and per seedling as calculated from Hill measurements. In the herbicide treated seedlings lower amounts of chlorophylls and carotenoids were found with decreasing ratios of chlorophylls/carotenoids and higher ratios of xanthophylls/β‐carotene. The ratios of chlorophyll a/benzoquinones decreased with regard to the control data. The accumulation of the single benzoquinones (on a chlorophyll basis), as related to the respective control values, is greater for α‐tocopherol, less for plastoquinone‐9 and even less for α‐tocoquinone. From the data obtained it is assumed that propachlor induces a state of senescence in the chloroplast. Propachlor seems to antagonize the known effects of exogenous indol‐3‐acetic acid. Questions of interaction of herbicide/phytohormone in this connection are discussed.
The effect on yield of mixtures and sequences of herbicides for the control of Alopecurus myosuroides Huds. and broad‐leaved weeds in winter cereals
Authors: WILSON B.J.
Published: July 2006

Mixed infestations of Alopecurus m yosuroides Huds. and broad‐leaved weeds in winter cereals were controlled with a commercial formulation of ioxynil + bromoxynil + mecoprop. used in mixtures or as sequences with isoproturon or clofop‐isobutyl. As well as controlling A. myosuroides the mixtures, applied in the autumn, gave good control of Veronica persica Poir., Galium aparine L. Lilhospermum arvense L. and Viola arvensis Murr. weeds which were resistant to isoproturon used alone.

A. myosuroides had the major influence on crop yield in three experiments. High infestations of A. myosuroides reduced the broad‐leaved weeds so that crop yields were only slightly improved when all the weeds were controlled compared with the control of A. myosuroides alone. In the remaining experiment. V. persica was very competitive with wheat; additional control of A. myosuroides improved yields considerably.

Ioxynil + bromoxynil + mecoprop gave better final control of broad‐leaved weeds when applied in the spring rather than the autumn but the sequence of a spring application following isoproturon or clofop‐isobutyl in the autumn did not improve yields compared with the mixtures applied in the autumn. In all experiments, the highest yields were obtained from controlling both A. myosuroides and broad‐leaved weeds in the autumn, provided that good control of A. myosuroides was obtained.
The biology and control of Lolium rigidum as a weed of wheat
Authors: MONAGHAN N. M.
Published: July 2006

Lolium rigidum Gaud. is an important weed of winter crops in some countries with Mediterranean‐type climates. This paper reviews L. rigidum competition in wheat, factors influencing populations of this weed and the effect of control of L. rigidum numbers on wheat yields.
The biology of African feather grass (Pennisetum macrourum Trin.) in Tasmania, I. Seedling establishment
Authors: HARRADINE A. R.
Published: July 2006

Seedling establishment of Pennisetum macrourum was studied in a series of glasshouse and field experiments. Maximum germination of 88% occurred at a constant temperature of 30C. In the glasshouse, highest seedling establishment was obtained from seeds buried 1 cm deep; it was less than 25% from seeds sown on the soil surface. Dormancy was induced in seeds buried 8 cm deep but only 6.4% remained viable after 6 months. Few viable seeds of P. macrourum were found in the soil and only one seedling was observed to establish in the field over a 20 month period. Up to 98% of seedlings transplanted into the field established successfully. The results suggest that reproduction by seed would not be a major problem in the control of P. macrourum.
Studies on competition between Setaria anceps and Eleusine indica
Authors: HAWTON D. , DRENNAN D.S.H.
Published: July 2006

Experiments were conducted at Kairi. Queensland. Australia on the competitive effects or Eleusine indica (L.) Gaertn. on Setaria anceps Stapf. ev. Nandi. In one experiment S, anceps top dry weights and seed yields were reduced to a similar extent by 20, 40. 80 or 164 (unthinned) E. indica plants/m2. Similarly, the dry matter yields from populations of 20–164 plants/m2 of E. indica did not differ significantly. Varying the density of S. anceps from 6 to 9.3 plants/m2 had little effect on the yield of either species. The mean production of E. indica seed was 1968 kg/ha or approximately 5.3 109 seeds/ha.

In two experiments where equal populations of both species were planted at varying times in relation to each other the above ground dry matter yield of S. anceps was not significantly affected when E. indica emerged 2 weeks or later than S. anceps. This was true whether the S. anceps was planted in rows or uniformly throughout the plot. Ina third, similar experiment S. anceps top dry matter was significantly reduced by 21% when the E. indica emerged 2 weeks after the crop.

In a time of weeding experiment, removal of E. indica for the first 13 days after planting was sufficient to prevent a significant reduction in S. anceps top dry matter and seed yields. In this experiment the two species were shown to be mutually exclusive.
Studies on competition between Macroptilium atropurpureum and Crotalaria goreensis
Authors: HAWTON D. , DRENNAN D.S.H.
Published: July 2006

Experiments were conducted at Walkamin, Queensland, Australia on the competitive effects of Crotalaria goreensis Guill. & Perr. on Macroptilium atropurpureum (DC.) Urb. cv. Siratro. In one experiment it was shown that varying C. goreensis densities of 10, 20, 40 and 200 plants/m2 produced successive reductions in M. atropurpureum yields and successive increases in C. goreensis yields. Varying the M. atropurpureum density from 2.3 to 6 plants/m2 did not significantly affect the yield of either species. Two hundred C. goreensis plants/m2 produced approximately 500 106 seeds/ha.

In three time of emergence experiments it was shown that the competitive ability of one species relative to the other varied with environmental factors. In one of these experiments with equal numbers of each species C. goreensis lowered M. atropurpureum top dry matter yield only when the former species emerged 2 weeks prior to the M. atropurpureum. When there were many more plants of C. goreensis present, emergence of both species at the same time lowered M. atropurpureum top dry matter yield in one experiment and emergence of C. goreensis 2 weeks after the M. atropurpureum lowered the dry matter yield of the latter species in a third experiment.

In a time of weeding experiment it was shown that under the particular environmental and plant density conditions prevailing removal of C. goreensis for 12 days after planting was sufficient to prevent a reduction in M. atropurpureum dry matter. In this experiment it was also shown that under these conditions the two species were not mutually exclusive. In mixtures the C. goreensis provided physical support to the M. atropurpureum, enabling the latter species to intercept more light energy than it could when growing in monoculture.
Etude de la dynamique d'une communaute adventice: I — Evolution de la flore adventice au cours du cycle vegetatif d'une culture
Authors: BARRALISet G. , CHADOEUF R.
Published: July 2006

Un dispositif expérimental a été mis en place pour comparer les effets du travail du sol et du désherbage chimique sur la dynamique d'une communauté adventice (agrophytocénose). Les auteurs décrivent la méthodologie détude et présentent la flore adventice du ce dispositif. Au cours du cycle cultural, la densité des mauvaises herbes passe par un maximum qui se situe en avril dans l'orge d'hiver et en mai dans l'orge de printemps. Le stock en semences viables du sol s'élève à environ 7000 individus par m2 sur 30 cm de profondeur et les levées de mauvaises herbes du semis à la récolte de l'orge n'ont représentê que 6.6% de ce stock. La densité des semences dans le sol est plus élevée entre 0–10 cm et 10–20 cm qu'entre 20–30 cm; leur viabilité est supérieure à 80% pour la majorité des espèces et elle est indépendante de la profondeur d'enfouissement.
Effect of benzoylprop‐ethyl on uptake, transport and metabolism of 32P in Avena fatua L. and Triticum aestivum L.
Authors: BERGMANNOVÁ EVA , TAIMR L.
Published: July 2006

The effect of benzoylprop‐ethyl on plant weight, root uptake, transport and metabolism of 32P in wild oat and wheat plants was examined 4 h, 1,3 and 9 days after treatment. The fresh weight of wild oat plants was significantly reduced, due to herbicide action only, by day 9 after treatment. By day 3, shoot weight was decreased while root weight was significantly increased by 47%. No significant changes in plant weight were caused by benzoylprop‐ethyl in wheat plants.

Uptake of 32P by treated wild oat plants decreased by 39% compared with the control, by day 9, after an initial increase; uptake of 32P was not significantly influenced in wheat plants. By day 1 transport of 32P to the shoots was significantly reduced in wild oat plants by 34%, whereas in wheat plants it was significantly increased by 35%.

Metabolism of 32P was already hampered in wild oat plants 4 h after treatment. The content of 32P was reduced on the first two sampling dates in both the roots and shoots of treated plants in all fractions except in DNA in the shoots. On day 3, this decrease was apparent especially in organic, lipidic and nucleic acid fractions in the shoots; incorporation of 32P into lipidic and RNA fractions was significantly inhibited on day 9 in both the roots and shoots of treated wild oat plants. Wheat plants responded most strongly to benzyoylprop‐ethyl on day 1 after treatment, when 32P incorporation into all fractions except DNA was hampered. Differences between treated and control wheat plants gradually levelled off on days 3 and 9 after treatment.
Effets de divers herbicides sur la croissance mycélienne de souches de Botrytis cinerea pers et de Penicillium expansum Link, sensibles ou résistantes à certains fongicides
Authors: ET P. LEROUX , GREDT M.
Published: July 2006

Sur les 70 herbicides expérimentés. 38 sont faiblement fongitoxiques pour Botrytis cinerea (CI 50, concentration inhibant la vitesse de croissance mycélienne de 50%, égale ou supérieure, à 100 g herbicide/ml milieu nutritif) et parmi ceux‐ci, 10 sont sans effect mme à 1000g/ml. Les produits les plus actifs (CI 50 inférieure à 10 g/ml) sont la chlorthiamide, le dichlobénil, le nitrofène, la propyzamide et des dérivés phénoliques (DNOC, ioxynil, PCP). Dans la plupart des cas Pénicillium expansum est moins sensible que Botrytis cinerea sauf vis à vis de l'endothal, du propanil, du prynachlor et de certaines urées substituées.

Les souches résistantes aux fongicides benzimidazoles (carbendazime, thiabendazole.) présentent une sensibilité accrue à certains herbicides carbamates (barbane, chlorbufame.); ceci indique l'existence d'une résistance croisée négative entre ces deux groupes de pesticides antimitotiques. Les souches résistantes aux fongicides imides‐cycliques (iprodione, procymidone, vinchlozoline) et à divers composés aromatiques (biphényle, chloronèbe. dicloran.) peuvent également ltre à des herbicides bipyridiliums, dinitroanilines, diphényléthers, à la chlorthiamide, au dichlobénil et à l'oxadiazon. Cette résistance croisée entre des pesticides à modes d'action biochimique différents reste à expliquer.
Viability of herbicide‐treated seeds of Eupatorium odoratum L.
Authors: ETEJERE E. O.
Published: July 2006

The 75–80% viability of Eupatorium odoratum seeds was found to be affected by the temperature of the environment where they were stored. The loss of viability increased with longer periods of storage. Seeds stored under — 10°C or 8°C still retained their viability after 26 months, those stored under 27.5°C or 37°C lost their viability during the same period.

There was a gradual loss of viability of herbicide‐treated seeds stored under — 10°C or 8°C. The rate of loss was greater for herbicide‐treated seeds stored under 27.5°C and 37°C and eventually led to the complete loss of viability after a short storage period of up to 13 months. EPTC and molinate had the greatest effects on seed viability.
Einfluß von Diclofop‐methyl auf Wachstum und Entwicklung der Keimlinge von Zea mays L.*
Authors: HOPPE H. H.
Published: July 2006

Diclofop‐methyl, ein herbtzider Wirkstoff aus der Gruppe der Di(phenoxy)propiosäurederivate, hatte keinen Einfluß, auf die Keimung der Samen von Zea mays. Wurden vorgekeimte Maisoder Bohnenkeimlinge mit dem Wirkstoff behandelt, so kam es beim Mais bereits im Bereich niedriger Wirkstoffkonzentrationen zu einer Hemmung des Keimwurzelwachstums, während die Bohne wesentlich unempfindlicher reagierte. Innerhalb der ersten 24 Std, nach der Herbizidbehandlung war die Wirkung auf dus Längenwachstum der Maiskeimwurzeln reversibel, wenn die Keimlinge auf herbizidfreies Medium übertragen wurden. Höhere Konzentralionen von Diclofop‐methyl (≥10−6 M) leiteten an den Keimwurzeln eine Nekrose ein, die etwa am 2. Tag nach der Behandlung im Bereich der Teilungsund Streckungszonen der Wurzelspitzen sichtbar wurde und sich dann über die Wurzel zum Korn hin ausbreitete‐ Das Herbizid erhöhte das Frisch‐ und Trockengewicht sowie den Trockcnsubstanzgehalt der Keimwurzelspitzen von Zea mays. Diese Effekte konnten auf eine Anreicherung von Zellwandmaterial in den herbizid‐behandelten Wurzelspitzen zurückgeführt werden. In Gegenwart von Hydroxyharnstoff”, einem selektiven Hemmstoff der Zellteilung, war die Wirkung von Diclofopmethyl auf das Längenwachstum der Kcimwurzeln zwar abgeschwächt, jedoch nicht aufgehoben. Aus diesen Ergebnissen kann gefolgert werden, daß Diclofop‐methyl in Prozesse eingreift, die sowohl an der Zellteilung als auch an der Zellstreckung mitwirken.
Emergence patterns of weed seedlings in relation to cultivation and rainfall
Authors: ROBERTS H. A. , POTTER MARGARET E.
Published: July 2006

In experiments over 4 years, separate field plots were cultivated once only at 2‐week intervals and the weed seedlings recorded weekly. Soil disturbance resulted in a flush of seedlings of which 90% appeared within 10 weeks after cultivation in early spring and within 3 weeks after cultivation in summer. Weekly emergence then returned to the level prevailing on undisturbed soil. The species composition of the seedling populations varied with the time of year at which the soil was disturbed. In each year there was a spring flush of seedlings, probably associated with rising soil temperature; subsequent flushes were coincident on cultivated and undisturbed soil and were related to the rainfall pattern. In each year there were periods when lack of soil moisture restricted emergence, and this appeared to be the over‐riding factor determining seedling numbers. When cultivations were followed by long dry periods which prevented germination, the numbers of seedlings appearing when rain ultimately fell were no different from those when the soil was disturbed just before the rainfall.
The threat posed by alien weeds in Israel
Authors: DAFNI AMOTS , HELLER DAVID
Published: July 2006

Summary: Résumé: Zusammenfassung

The alien weed flora of Israel comprises forty species out of a total of seventy‐seven adventive species represented here. Twenty‐nine of them occur in other countries of the Middle East and they probably reached Israel through these countries: the rest me regarded as direct imports from their countries of origin. About nine species have already become major weeds, while the other twenty‐nine species, which are known as noxious weeds from other parts of the world, are in the active process of spreading and reaching this status.

Details are given of the ecology, distribution, origin, first record or presence in Israel, agricultural importance and population dynamics for each species.

La menace des espèces adventices de manvoises herbes en Israël

La flore des espèces adventices de mauvaises herbes en Israël comprend quarante‐deux espéces sur un total de soixcinte‐dixsept espéces de mauvaises herbes représentées ici. Vingt‐neuf d'entre elles apparaissent dans d'autres régions du Moyen Orient et elles ont probablement atteint Israël à travers ces régions, les autres sont considérées comme des importations directes depuis leurs pays d'origine. Neuf espèces environ sont dèjà devenues des mauvaises herbes importantes, cependant que vingt‐neuf autres, qui sont connues comme des espèces nuisibles dans les autres parties du monde, sont en passe de le devenir en Israël et sont en rapide expansion.

Des détails sont donnés sur l'éeologic, la distribution l'origine, la première apparition ou la présence en Israël, l'importance agricole et la dynamique de la population pour chacune des espèces.

Gefahr durch eingeschleppte Unkräuter in Israel

Von den insgesamt in Israel vorkommenden 77 Adventivpflanzen zählen 40 Arten zu den Unkräutern. Von diesen Adventivpflanzen kommen 29 in anderen Ländern des Nahen Ostens vor und dürften von dort aus nach Israel gekommen sein, die restlichen Arten sind Direktimporte Aus ihren Herunftsländern, Ungefähr 9 Arten sind bereits zu Hauptunkrautern geworden, während die restlichen 29, die als gefährhehe Unkräuter in andercn Teilen der Welt bekannt sind. sich entsprechend ausbreiten und somit künftig auch hierzu gezählt werden müssen.

Für jede Art werden nähere Angaben gemacht zu: Ökologie, Verbreitung, Herkunft, erstmaliges Auftreten in Israel, landwirtschaftliche Bedeutung und Populationsdynamik.
The selective control of Poa trivialis by dalapon in perennial ryegrass crops grown for seed
Authors: OSWALD A. K.
Published: July 2006

Summary: Résumé: Zusammenfassung

The effects of dalapon applied in March and April at doses between 1·7 and 2·8 kg/ha a.e. on Poa trivialis present in crops of perennial ryegrass grown for seed, were investigated. Good control of P. trivialis was achieved at all doses sprayed at both times. Reductions in numbers of inflorescences and yield of seed of perennial ryegrass were however recorded, particularly after applications in March. Differences in the response of perennial ryegrass cultivars were also observed; cultivar S.23 was more susceptible to the herbicide than cultivar S.24. The results also suggest that the variation in response of cultivar S.24 in different experiments within the study may be due to the influence of climatic factors.

Lutte sélective contre Poa trivialis avec le dalapon dans des cultures porte‐graines de ray‐grass vivace.

Les effets du dalapon, appliqué en mars et en avril à des doses comprises entre 1,7 et 2,8 kg/ha (é.a.) sur Poa trivialis présent dans des cultures porte‐graines de ray‐grass vivace, ont étéétudiés. Une bonne efficacité sur Poa trivialis a été obtenue à toutes les doses appliquées aux deux époques. Toute fois, des réductions du nombre des inflorescences et des rendements en graines du ray‐grass vivace, ont été constatés, particuliérement aprés les applications faites en mars. Des différences entre les réactions des cultivars ont été aussi observées: le cultivar S.23 s'est révélé plus sensible que le cultivar S.24. Les résultats suggèrent que les réactions différentes du cultivar S.24 dans diverses expériences comprises dans ce travail, peuvent également êre dues à l'influence de facteurs climatiques.

Selektive Bekämpfung durch Dalapon von Poa trivialis in Deutschem Weidelgras für Samenproduktion

Die Wirkung von Dalapon gegen Poa trivialis in Kulturen zur Samengewinnung von Deutschem Weidelgras wurde untersucht. Im März und April wurden Dosierungen zwischen 1,7 und 2,8 kg/ha appliziert. Poa trivialis konnte in alien Dosierungen und an beiden Behandlungszeitpunkten bekämpft werden. Minderungen in der Zahl der Blutenstände und Grassamenerträge von Deutschem Weidelgras wurden jedoeh festgestellt, insbesondere nach Applikation im März. Ebenfalls reagierten die Weidelgrassorten untersehiedlich. Sorte S.23 war gegen das Herbizid empfindlicher als Sorte S.24. Die Resultate deuten auch an, dass die unterschiedliche Reaktion von Sorte S.24 in den Experimenten dieser Untersuchung auf den Einfluss von Klimafaktoren zurückgeführt werden könnte.
Effect of some substituted benzonitriles on photosynthetic activity of spinach and wheat in vivo and in vitro
Authors: SZIGETI ZOLTÁN , SÁRVÁRI ÉVA , BUJTÁS CLAIRE
Published: July 2006

The inhibitory effects of nine nitro and/or bromo‐substituted benzonitrile compounds on the photosynthetic electron flow in isolated chloroplasts and on the in vivo CO2 fixation of spinach (Spinacia oteracea L.) and wheat (Triticum aesticum L. cv. Bezoslaya) were investigated.

Bromoxynil and 3‐nitro‐5‐hromo‐4‐hydroxy‐bcnzonitrile were the strongest and equally effective inhibitors of Ihe in vivo CO2 fixation of spinach, hut in wheat the nitro‐bromo‐compound is ineffective and 3‐nitro‐benzonitrile is even more inhibitory than bromoxynil. None of the substances affected DCPIPH → methylviologen reduction. In the inhibition of the DCPIP reduction only the 3,5‐disuhstituted 4‐hydroxy‐derivatives were effective. The fact that these compounds affect only the PS II reaction with both H2O and DPC as electron donors suggests a site of inhibition on the reducing side of PS II, between Ihe PS II reaction centre and ihe DCPIP Site. It is suggested that in the inhibition of the DCPIP reduction only steric factors are important and the different electron configuration of the sterieally similar molecules may be involved only in the absorption and translocation processes of the compounds.
Effects of hoeing and rototilling on some aspects of the population dynamics of pure stands of Portulaca oleracea L. (purslane)
Authors: And KIYOKO MIYANISHI , B.CAVERS PAUL
Published: July 2006

Two naturally‐established pure stands of Portulaca oleracea L. were used to study the effects of five disturbance schedules (early, midseason, late, repeated and no disturbance) on the development of purslane populations. In one stand disturbance was by rototilling and in the second stand by hoeing. In most disturbed plots, the re‐established stands had densities which were not significantly less than those of the control plots. These stands were composed of plants established by seed germination (seed plants) and by regeneration of roots on severed stems (stem plants) or shoots on root and stem bases (root plants). The composition of these stands depended on the type of disturbance. Undisturbed stands were composed predominantly of seed plants. Disturbed stands had fewer than 55% seed plants. Hoeing resulted in a greater proportion of stem plants and a lower proportion of root plants than rototilling. All disturbances resulted in decreased dry matter yields per unit area. The maximum yields for the controls in the two stands were similar, regardless of differences in density, mean dry weight, size class distribution and time of establishment. Early disturbance resulted in significant decreases in seed capsule production while disturbance late in the season had minimal effects on seed production. The implications for control of purslane in crops are discussed.
Fate of terbutryn in macrophyte‐free and macrophyte‐containing farm ponds
Authors: MUIR D.C.G. , PITZE M. , BLOUW A.P. , LOCKHART W.L.
Published: July 2006

Terbutryn (2‐ethylamino‐4‐(tert‐butylamino)‐6‐methylthio‐s‐triazine) was applied in June 1978, to two farm ponds (A and C) near Winnipeg. Canada, to give 100 μg/l water concentrations. The persistence of the herbicide and its degradation products was monitored over a 61‐week period following application. The half‐life of terbutryn m the water column ranged from 3 weeks in Pond C, which contained heavy growths of cattails (Typha sp.) and duckweed (Lemna sp.), to 30 days in Pond A. which was free from aquatic macrophytes, Terbutryn residues m sediment reached a maximum of 1.4 μg/g (dry wt) in Pond A and 0.5 μg/g in C. Maximum concentrations of N‐deethylated terbutryn (2amino‐4‐(tert‐butylamino)‐6‐methylthio‐s‐tria‐zine)(DET) were 14.4 μg/l in Pond A water after 61 weeks and 0.14 μg/g in Pond C sediment after 30 weeks. The maximum concentration of hydroxy‐terbutryn (2‐hydroxy‐4‐ethyl‐amino‐6‐(tert‐butylamino)‐s‐triazine) (HT) observed in pond water was 6.4 μg/l in Pond C after 7 weeks. HT was not detected in sediment (<0.05 μg/g) during the study. After 61 weeks, about 50% of the terbutryn that was added could still be accounted for in Pond A and 35% in Pond C. Terbutryn. DET and HT represented an estimated 71, 28 and 1%, respectively, of total terbutryn remaining in Pond A and 65, 29 and 6%, respectively, of that remaining in Pond C, 61 weeks after application, Terbutryn residues in Typha ranged from 0.3 μg/g (dry wt) in the shoot to 3.3 μg/g in the roots. After 12 weeks, terbutryn residues in plants (Pond C) were estimated to account for 1 to 4% of the herbicide in the pond.
Inhibition of photosynthetic pigments in cucumber cotyledons as a principle for a bioassay with fluridone
Authors: And D.M. DREXLER , FLETCHER R.A.
Published: July 2006

The response of etiolated cucumber (Cucumis sativus L. cv. National Pickling) cotyledons to fluridone was investigated in terms of inhibition of photosynthetic pigments, and utility as a bioassay. At a light intensity of 35 W/m2, chlorophyll levels were higher in the controls, than at either 12.9 W/m2, or 75 W/m2. Fluridone inhibition was also more pronounced at that intensity. Significant differences between treatments were established as early as 24 h after exposure to light, when at the lowest fluridone concentration of 0.001 μg/ml, chlorophylls and carotenoids were inhibited 25 and 35% respectively. The system's simplicity and sensitivity suggest its use as a bioassay. It is shown that simple monochromatic absorbances of acetone extracts can satisfactorily estimate chlorophylls and carotenoids. Concentrations of fluridone as minute as 10−9 moles/ litre are easily delected, and the system could feasibly detect even lower levels.
Modification des teneurs en ATP, glucose, fructose et saccharose dans des plantules de concombre (Cucumis sativus) sous l'action de divers herbicides
Authors: DECLEIRE M. , DE CAT W.
Published: July 2006

L'application durant 3 jours de doses létales d'atrazine, de MCPA, de dichlobénil, d'alachlore et de paraquat par voie racinaire et/ou par voie foliaire a permis de démontrer que la phytotoxicité des herbicides n'est pas nécessairement liée à une diminution d'ATP. L'atrazine administrée par voie racinaire provoque dans les feuilles une diminution de 57–88% de glucose et de fructose; de 70–97% de saccharose. Dans les ratines les pertes sont respectivement de 14–60% et 33–96%.

L'atrazine par voie foliaire accentue davantage les pertes en glucides. Après traitement au MCPA, le glucose des feuilles croit de 250 a 890%; le fructose de 240 à 630%; le saccharose de 110 a 170%. Dans les racines, le glucose augmente de 150 à 420%; le fructose de 160 à 450% tandis que le saccharose diminue de 20–39%. L'alachlore diminue les sucres réducteurs des feuilles et les augmente dans les racines. Le diehlobénil fait baisser les glucides des feuilles les deux premiers jours et les fait croitre le troisième jour. Les auteurs proposent quelques formules permettant de caractériser la nature des herbicides d'après les rapports des teneurs des constituants analysés.
The use of post‐luminescence decay and fluorescence emission to detect initial herbicide toxicity.
Authors: DEVLIN ROBERT M. , ZBIEC IRENA I. , MURKOWSKI ANTONI J. , KARCZMARCZYK STANISLAW J.
Published: July 2006

The influence of pyrazon. norflurazon and glyphosate on post‐luminescence decay and fluorescence emission was studied. Pyrazon and norflurazon significantly increased post‐luminescence decay in wheat (Triticum vulgare L) and cuckoo flower (Cardamine pratensis L.). Pyrazon was much more active than norflurazon m this respect, No influence of’glyphosate on post‐luminescence and the emission ol” fluorescence was observed.

Measurements of post‐luminescence decay and fluorescence emission can serve to define some aspects of herbicidal pbyto‐toxicity and provide information on the initial action of those compounds that inhibit photosynthesis.
A note on the biological control of Scurrula cordifolia (Wall.) G. Don by another mistletoe in Sivalik Hills (India)
Authors: PUNDIR Y.P.S.
Published: July 2006

Observations made on the hyperparasitism ofViscum loranthiElmer on the parasitic weedScurrula cordifolia(Wall.) G. Don in the Sivalik Hills suggest that the hyperparasite is providing effective biological control of the latter. Moreover, as the hyperparasite appears to attack only mistletoes, it can probably be introduced with safety into other localities whereS. cordifoliais spreading.