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1.
R. S. L. JEATER 《Weed Research》1964,4(2):133-141
Summary. In Malayan rubber plantations where the weed flora was dominated by grasses paraquat was superior to diquat as a herbicide. At the rates needed to give satisfactory grass weed control paraquat also gave an adequate control of broad-leaved weeds.
The rate of paraquat needed varied between 0.75 and 1.25 lb/ac depending on the weed flora and the growth stage of the rubber trees. In young rubber 1.0–1.25 lb/ac gave 8–10 weeks' control, but in mature rubber there was only 20% recovery 6 months after an application of 0.75 lb/ac. Where weed regrowth was very rapid after the initial spray, as in the case of Paspalum conjugation in young rubber, a second application some 2–3 weeks after the first was an advantage. The volume of water in which it was applied was not critical.
Rain falling soon after application did not reduce the herbicidal activity of paraquat. Paraquat did not injure rubber trees providing it was not sprayed onto green tissue and this feature combined with its inactivation by soil made it safe to use from a very early stage in the growth of the rubber trees.
L'évaluation du paraquat et du diquat pour la lutte contre les mauvaises herbes dans les plantations de caoutchouc 相似文献
The rate of paraquat needed varied between 0.75 and 1.25 lb/ac depending on the weed flora and the growth stage of the rubber trees. In young rubber 1.0–1.25 lb/ac gave 8–10 weeks' control, but in mature rubber there was only 20% recovery 6 months after an application of 0.75 lb/ac. Where weed regrowth was very rapid after the initial spray, as in the case of Paspalum conjugation in young rubber, a second application some 2–3 weeks after the first was an advantage. The volume of water in which it was applied was not critical.
Rain falling soon after application did not reduce the herbicidal activity of paraquat. Paraquat did not injure rubber trees providing it was not sprayed onto green tissue and this feature combined with its inactivation by soil made it safe to use from a very early stage in the growth of the rubber trees.
L'évaluation du paraquat et du diquat pour la lutte contre les mauvaises herbes dans les plantations de caoutchouc 相似文献
2.
Summary. Herbicide combinations containing paraquat were synergistic and provided control of established Agropyron repens (L.) Beauv. (quackgrass) sods for the entire growing season. Paraquat applied at 0–5 lb/ac with simazine or diuron at 4–0 lb/ac was more phytotoxic than either herbicide applied singly and the enhanced activity was more than additive. This synergism was not due to increased absorption or translocation of either herbicide in aerial portions of the plant. Paraquat applied to the shoot increased the susceptibility of quackgrass to simazine action through the soil. Pre-treatment of quackgrass with aminotriazole or amitrole-T at 10 lb/ac 7 days before paraquat application at 0–5 lb/ac provided increased toxicity over that obtained when the two herbicides were applied together or singly. Subsequent studies indicated that aminotriazole applications prior to shoot destruction by either paraquat or clipping resulted in more chronic aminotriazole toxicity. Using methyl-14C-paraquat it was found that aminotriazole pre-loading also increased the movement of paraquat in and out of the treated leaf. This increase was even more pronounced with amitrole-T. When the two herbicides were applied together, antagonism in absorption and translocation occurred. Action synergique de combinaisons d'herbicides comprenant du paraquat sur Agropyron repens (L.) Beauv. 相似文献
3.
D. W. R. HEADFORD 《Weed Research》1966,6(4):304-313
Summary. Paraquat, amitrole-T and disodiumn methylarsonate (DMA) were evaluated for the control of the stoloniferous grass Paspalum conjugatum in young rubber plantations in Malaya. The herbicides were tested alone, in mixtures and in split applications. Paraquat at 0–5 lb/ac gave good initial desiccation but regeneration was extremely rapid and repeated sprays of 0–25 lb/ac were required for a long period of suppression. Amitrole-T at 15 lb/ac was very slow to act but gave complete kill after 10 weeks. DMA at 8–12 lb/ac gave marked suppression, but regeneration rapidly developed after 8 weeks. Mixtures of either amitrole-T or DMA with paraquat gave less than the expected additive effects of the components, indicating an antagonistic action. Sub-lethal rates of amitrole-T or DMA applied to regenerating shoots after paraquat treatment gave results inferior to those from higher rates of the herbicides alone.
When paraquat was applied 2 weeks after an initial sub-lethal dose (0.375 lb/ac) of amitrole-T, desiccation was rapid and complete eradication was achieved; this did not occur when a low rate of DMA was used as the first spray. In terms of both speed of kill and final effect, a split application of a low rate of amitrole-T followed by paraquat was the most effective treatment. A possible explanation of the apparent synergism between amitrole-T and paraquat applied in this way is advanced and suggestions for further work outlined.
Une méthode améliorée pour la lutte centre Paspalum conjugatum avoc l'amitrole-T et le paraquat 相似文献
When paraquat was applied 2 weeks after an initial sub-lethal dose (0.375 lb/ac) of amitrole-T, desiccation was rapid and complete eradication was achieved; this did not occur when a low rate of DMA was used as the first spray. In terms of both speed of kill and final effect, a split application of a low rate of amitrole-T followed by paraquat was the most effective treatment. A possible explanation of the apparent synergism between amitrole-T and paraquat applied in this way is advanced and suggestions for further work outlined.
Une méthode améliorée pour la lutte centre Paspalum conjugatum avoc l'amitrole-T et le paraquat 相似文献
4.
R. C. BRIAN 《Weed Research》1966,6(4):292-303
Summary. In a number of plant species, the biological activity of diquat and paraquat was increased by an increase in environmental humidity. This improved activity resulted from an increase in both uptake and movement.
High humidity was more effective after treatment than before it, and durations of 8 hr or more were required to produce the maximum effect. When periods of low humidity of up to 16 hr were interposed between treatment and high humidity, there was no significant effect on the activity of diquat in darkened tomato or sugar beet.
The increase in activity occurred both in the dark and in the light, and it is therefore concluded that humidity does not exert its effect by modifying the degree of stomatal opening.
Experiments were carried out with wheat using two air humidities combined with different soil moisture contents, ranging from saturated down to only 30% of water-holding capacity. Greatest movement occurred where high air humidity was combined with low soil moisture, and least where low air humidity was combined with high soil moisture. It is concluded that diquat and paraquat would be most effective in the field when sprayed under dry soil conditions in late afternoon or evening when increased humidity (and darkness) can follow soon after treatment.
Les sels quatemaires de bipyridylium
Effet de l'humidité atmosphérique et de l'humidité du sol sur l'absorption et la migration du diquat et du paraquat dans les plantes 相似文献
High humidity was more effective after treatment than before it, and durations of 8 hr or more were required to produce the maximum effect. When periods of low humidity of up to 16 hr were interposed between treatment and high humidity, there was no significant effect on the activity of diquat in darkened tomato or sugar beet.
The increase in activity occurred both in the dark and in the light, and it is therefore concluded that humidity does not exert its effect by modifying the degree of stomatal opening.
Experiments were carried out with wheat using two air humidities combined with different soil moisture contents, ranging from saturated down to only 30% of water-holding capacity. Greatest movement occurred where high air humidity was combined with low soil moisture, and least where low air humidity was combined with high soil moisture. It is concluded that diquat and paraquat would be most effective in the field when sprayed under dry soil conditions in late afternoon or evening when increased humidity (and darkness) can follow soon after treatment.
Les sels quatemaires de bipyridylium
Effet de l'humidité atmosphérique et de l'humidité du sol sur l'absorption et la migration du diquat et du paraquat dans les plantes 相似文献
5.
Summary. A series of experiments with 2,6-dichlorobenzonitrile is described. It is demonstrated that 2,6-DBN is highly phytotoxic when applied as a soil drench or preemergence spray in the greenhouse, but measurement of crop and weed responses in the field, accompanied by quantitative assessment of the chemical residues in the soil, indicates that the persistence of 2,6-DBN following surface application is short under both tropical and temperate (winter) conditions. It is, however, extended from a few days to several weeks if the chemical is incorporated into the soil immediately after application. Under tropical conditions the effect of 4 lb/ac applied to the surface is roughly equated to 2 lb/ac immediately watered-in, 1.5 lb/ac immediately raked-in, or 1 lb/ac both watered- and raked-in, and a delay of 4 hours between application and incorporation is shown to reduce the effectiveness of the chemical by about half. The lack of persistence of 2,6-DBN when applied to the soil surface, and the modifying influence of soil incorporation and watering is attributed to its high vapour pressure (5 × I0−4 mm Hg at 20° C) and its relatively low solubility in water (20 ppm at 25° C).
Le rapporl entre l'activité herbicide du 2,6-dichlorobenzonitrile et sa persistance dans le sol 相似文献
Le rapporl entre l'activité herbicide du 2,6-dichlorobenzonitrile et sa persistance dans le sol 相似文献
6.
E. G. CUTHBERTSON 《Weed Research》1964,4(2):123-132
Summary. Comparative experimental results with dalapon-sodium and paraquat for the control of barley grass ( Hordeum leporinum Link) in lucene and subterranean clover pasture are reported. Sprays were applied 3–4 days after a simulated grazing.
At all rates tested (1–4 lb/ac), dalapon provided satisfactory control of, but did not eradicate, barley grass. Subterranean clover productivity was reduced substantially whether application was in May or July; lucerne growth was retarded by 4 lb/ac applied in July.
Paraquat applied at 0.06–0.25 lb/ac in May gave similar but somewhat less effective control than did dalapon. Some re-establishment of barley grass occurred as a result of late germinations following the May applications. Paraquat applied in July at 0.06 lb/ac gave unsatisfactory results, but at 0.12 and 0.25 lb/ac the control was comparable with that given by dalapon. Subterranean clover was damaged slightly by the May treatments but recovered quickly, after initial scorching, following applications in July. Lucerne was neither damaged nor retarded by paraquat.
The addition ofa wetting agent increased the efficacy of paraquat in controlling certain more tolerant annual grasses, but not barley grass.
Désherbage sélectif des pâtures ft des luzernes: lutte contre l'orge des lièvres 相似文献
At all rates tested (1–4 lb/ac), dalapon provided satisfactory control of, but did not eradicate, barley grass. Subterranean clover productivity was reduced substantially whether application was in May or July; lucerne growth was retarded by 4 lb/ac applied in July.
Paraquat applied at 0.06–0.25 lb/ac in May gave similar but somewhat less effective control than did dalapon. Some re-establishment of barley grass occurred as a result of late germinations following the May applications. Paraquat applied in July at 0.06 lb/ac gave unsatisfactory results, but at 0.12 and 0.25 lb/ac the control was comparable with that given by dalapon. Subterranean clover was damaged slightly by the May treatments but recovered quickly, after initial scorching, following applications in July. Lucerne was neither damaged nor retarded by paraquat.
The addition ofa wetting agent increased the efficacy of paraquat in controlling certain more tolerant annual grasses, but not barley grass.
Désherbage sélectif des pâtures ft des luzernes: lutte contre l'orge des lièvres 相似文献
7.
Summary. Trials with dalapon, paraquat and fenuron in 1963 and 1964, and with bromacil and amitrole-T in 1964, were carried out on mature Spartina sward. Dalapon, paraquat and fenuron all gave complete kill on some plots in 1963. In 1964, paraquat gave variable results and lower percentage kills than in 1963, whereas dalapon and fenuron were more consistent. Fenuron allowed a greater degree of regeneration than dalapon and was uneconomic at the high dose (60 lb/ac) required for complete kill. Dalapon gave the best results and with 100 lb/ac there was 98–100% kill 2 years after treatment. At 50 lb/ac results were initially good, but there was more regeneration in the second season after spraying. Bromacil at 5 and 20 lb/ac and a mixture of 5 lb/ac bromacil and 4 lb/ac amitrole-T maintained more than 99% kill lor 2 years after application.
La lutte chimique contre les formes fertiles de Spartina townsendii (s.l.) sur la cóte du Cheshire dans l'esluaire de la Dee I. Essais au champ sur des pelouses de Spartina 相似文献
La lutte chimique contre les formes fertiles de Spartina townsendii (s.l.) sur la cóte du Cheshire dans l'esluaire de la Dee I. Essais au champ sur des pelouses de Spartina 相似文献
8.
Summary. Diquat and sodium monochloroacetate (SMA) were used to desiccate seed crops of red beet in experiments from 1963 to 1965. The seed plants became brown and dry about 7 days after spraying and were then judged suitable for combine harvesting, although this was not done in these experiments. Yields of seed 7 days after spraying were as good as those from the control plants, but were lower than the control yields when harvested 14 days after spraying. In laboratory tests in moist sand at 20° C the percentage of the embryos which germinated was not markedly affected by diquat or SMA treatment. The emergence of seedlings in the field, however, was affected adversely by treatment of the seed crop with 11 and 22 oz/ac of diquat ion in 1963 and by SMA at 20 lb/ac in 1964 and 1965. Diquat at 6·6 oz/ac in 120 gal/ac water in 1964 and 1965 had no serious adverse effects on embryo emergence. Residues of diquat ion in seed varied from 2 to 4 ppm, but the impairment of embryo emergence by diquat was believed to be due to the premature arrest of growth of the seed on the desiccated plants.
It is concluded that when harvesting conditions are poor, desiccants could be valuable.
Influence des traitements dessicants et de la date de récolte sur le rendement et la qualité de la sentence de betterave rouge 相似文献
It is concluded that when harvesting conditions are poor, desiccants could be valuable.
Influence des traitements dessicants et de la date de récolte sur le rendement et la qualité de la sentence de betterave rouge 相似文献
9.
K. CARPENTER HELEN J. COTTRELL W. H. DE SILVA B. J. HEYWOOD W. G. LEEDS K. F. RIVETT MARGERY L. SOUNDY 《Weed Research》1964,4(3):175-195
Summary. The preparation of ioxynil, bromoxynil, and their salts is described, and information on solubilities and stability to storage is summarized. Although the toxicology of the herbicides is to be reported in greater detail, a preliminary statement is made here. Evidence of herbicidat activity under glasshouse conditions is indicated briefly, and supports the conclusion that both compounds are effective when applied to the foliage of a wide range of dicotyledon weed species. Seedlings of some weed species resistant to the phenoxy alkanoic acids are controlled under glasshouse conditions at doses as low as 0.125 lb/ac, and ioxynil has a wider range of activity than bromoxynil at these low doses. Graminaceous species tolerate 4–8 lb/ac of both herbicides without injury, and certain leguminous crops tolerate one or other herbicide at doses of 0.5–0.75 lb/ac. The contact action of the herbicides is rapid, there are also slower systemic effects, and seed germination is inhibited. In susceptible species the level of post-emergence activity is shown to be influenced by the growth stage of the weed, the distribution of herbicide on the foliage, and environmental factors of which light intensity appears to be most important.
Propriétés chimiques et biologiques de deux nouveaux herbicides: ioxynil et bromoxynil 相似文献
Propriétés chimiques et biologiques de deux nouveaux herbicides: ioxynil et bromoxynil 相似文献
10.
J. M. WAY 《Weed Research》1964,4(1):12-23
Summary. The effects of sub-lethal doses of MCPA-sodium on the morphology and yield of red beet, turnip and onion and on the morphology of spinach were studied in field and glasshouse experiments. Epinastic responses of beet were seen at 0.003 lb/ac a.c., but no serious formative effects or yield reductions occurred below 0–07 lb/ac and plants were only killed by doses above 0–1 lb/ac. Spinach was affected at 0–06 lb/ac, the lowest dose used, but the plants were not killed at 0–33 lb/ac. Epinasty in turnip occurred at 0–002 lb/ac, and at 0–01 lb/ac many of the roots were abnormal, while spraying with 0–1 lb/ac and above resulted in severe distortion or death of the plants. Onion was the least affected of all the crops studied. When a welting agent was included in the spray epinasty occurred at 0–3 lb/ac, but there were no serious formative effects or yield reductions below 1–0 lb/ac. The symptoms of injury in onion were often transitory because the affected parts were replaced as the bulb developed.
Effets de doses sub-léthatles de MCPA sur la morphologie et If rendement des cultures légumiéres. V. Betteraves, Epinards, Navets et Oignons 相似文献
Effets de doses sub-léthatles de MCPA sur la morphologie et If rendement des cultures légumiéres. V. Betteraves, Epinards, Navets et Oignons 相似文献
11.
DISTRIBUTION AND BREAKDOWN OF PARAQUAT IN SOIL 总被引：1，自引：0，他引：1
Summary. The degradation of paraquat dichloride in soil by Lipomyces starkeyi Lod. and Rij, was investigated spectrophotometrically and by 14C-labelled carbon dioxide emission. Breakdown occurred within the first 96 hr of incubation in cultures of soil of high organic content. Adsorption isotherms showed that soils rich in organic matter had a greater total adsorption of paraquat from solutions of concentration in excess of 250 ppm. Soil high in organic matter was fractionated by ultrasonic disintegration into its organic and inorganic components. Paraquat degradation occurred in cultures containing the former but not the latter. Slow transfer of 14C-labelled paraquat adsorbed on the organic components was shown to take place through a dialysis membrane to the much stronger adsorption sites on the inorganic components placed outside the membrane. It appears that decomposition of paraquat in soil by L. starkeyi occurs while the herbicide is weakly adsorbed on the organic soil components. Over a period of time (96 hr in one instance), slow transfer to the inorganic soil components rendered the paraquat unavailable for microbial degradation. Dispersion et decomposition du paraquat dans le sol Résumé. La décomposition du paraquat-dichlorure dans le sol par Lipomyces starkeyi Lod. ci Rij a étéétudiée par spectrophotométrie et par l'émission de gaz carbonique marqué au 14C. La décomposition survint durant les premières 96 heures d’incubation dans les cultures de sols à forte teneur en matière organique. Les isothermes d'adsorption montrè-rent que les sols riches en matière organique présentaient une d'adsorption totale du paraquat plus grande à partir de solutions dont la concentration dépassait 250 ppm. Les sols à forte teneur en matière organique furent fractionnés par désintégration aux ultra-sons en leurs composants organiques et minéraux. La dégradation du paraquat se manifesta dans les cultures contenant les premiers, mais pas dans celies contentant les seconds. Une lente migration du paraquat marqué au 14C adsorbé sur les composants organiques fut observée par dialyse à travers une membrane vers les lieux de plus forte adsorption dans les composants minéraux placés de l'autre côté de la membrane. II apparait que la décomposition du paraquat dans le sol par L. starkeyi se manifeste lorsque l'herbicide est faiblement adsorbé sur les composants organiques du sol. Au-delà d'une certaine durée (96 heures dans un cas) la lente migration vers les composants minéraux du sol mit le paraquat à l'abri de la dégradation microbienne. Verteilung und Abbau von Paraquat im Boden Zusammenfassung. Der Abbau von Paraquat-chlorid im Boden durch Lipomyces starkeyi Lod, und Rij wurde sowohl spektrophotometrisch als auch durch Messung der 14C-Kohlendioxydabgabe untersucht, Der Abbau erfolgte innerhalb der ersten 96 Stunden nach dcr Inkubation in Bodenkulturen mit hohem organischem Anteil. Die Adsorptions-isotherm en zeigten, dass Boden mit hohem Anteil an organischer Substanz mehr Paraquat aus einer Lösung mit einer Konzentration von mehr als 250 ppm adsorbierten. Boden mit hohem Anteil an organischer Substanz wurde durch Ultraschalldesintegration in seine organischen und anorganischen Bestandteilv zcrlegt. Abbau von Paraquat erfolgte in Kulturcn mit den organischen Bestand teil en, nicht jedoch in Kulturen mit anorganischen. Durch eine Dialysemembran erfolgte ein langsamer Ubertritt von 14C-markiertem Paraquat, das an die organischen Bestandteile adsorbiert war, an die viel starker adsorbierenden anorganischen Bestaudteile, die sich ausserhatb der Membran befanden. Bei schwacher Adsorption des Herbizids an organische Bod en best and teile erfolgt offensichtlich ein Abbau von Paraquat durch L. starkeyi. Mit der Zeit (in einem Fall innerhalb von 96 Stunden) wird Paraquat durch einen langsamen Ubertritt an die anorganischen Bodenbestandteile fiir Mikroorganismen unzuganglich. 相似文献
12.
Summary. Trials were conducted in East Anglia to compare direct-drilling following paraquat at 1 and 2 lb/ac with normal cultivations for both winter wheat and spring barley. The three treatments were compared at two levels of nitrogen.
With direct-drilled winter wheat, yields were higher after using paraquat at 2 lb/ac and at this rate there was little difference between direct-drilling and normal cultivations when 100 units of nitrogen were applied in spring. When only 50 units were given the results were more variable, with direct-drilling significantly outyielding normal cultivations in one trial, being outyielded in another and showing no difference in the third.
Yields of spring barley were slightly higher after paraquat at 2 lb/ac as compared with 1 lb/ac, but not significantly so. The time of application of paraquat influenced yield; when applied in December yields from direct-drilling and normal cultivations were similar, but when applied in February higher yields were recorded with normal cultivations.
Comparaison des doses de paraquat a utiliser avant un semis direct de dreales 相似文献
With direct-drilled winter wheat, yields were higher after using paraquat at 2 lb/ac and at this rate there was little difference between direct-drilling and normal cultivations when 100 units of nitrogen were applied in spring. When only 50 units were given the results were more variable, with direct-drilling significantly outyielding normal cultivations in one trial, being outyielded in another and showing no difference in the third.
Yields of spring barley were slightly higher after paraquat at 2 lb/ac as compared with 1 lb/ac, but not significantly so. The time of application of paraquat influenced yield; when applied in December yields from direct-drilling and normal cultivations were similar, but when applied in February higher yields were recorded with normal cultivations.
Comparaison des doses de paraquat a utiliser avant un semis direct de dreales 相似文献
13.
J. D. BANTING 《Weed Research》1967,7(4):302-315
Summary. Factors investigated included the susceptibility of Avena fatua L. at various stages of growth, the amount of moisture needed to activate di-allate in Regina heavy clay, the vapour action of di-allate in soil, the effect of organic matter on the availability of di-allate, and the persistence of di-allate and tri-allate in Regina heavy clay.
A. fatua sown at depths of 5–15 cm was killed by di-allate or tri-allate. as were seedlings treated at the 15–2-leaf stage. Seedlings of spring wheat ( Triticum aestivum L.) survived rates of 24 oz/ac if the shoots were 1–3 cm long prior to exposure.
When di-allate at 16 oz/ac was mixed with a 5 cm layer of Regina heavy clay (wilting point 19–6%) slightly less than 15% soil moisture was required to give complete control of A.fatua. Further experiments indicated that a large percentage of A. fatua seedlings were killed by the action of di-allate vapour in the soil.
In other tests the activity of di-allate and tri-allate was reduced when the percentage of organic matter in the soil was increased by adding peat. This could explain why there is little damage to wheat sown in treated soil of high organic content while similar rates can cause extensive damage in soils of low organic content.
Under comparable conditions tri-allate persisted for a longer period in the soil than di-allate. Both chemicals exhibited a lag period after which their breakdown appeared to follow a first-order reaction. Differences in the period of persistence were attributed to a much longer lag period and a slightly slower rate of biological breakdown for tri-allate as compared to di-allate.
Facteurs affectant l'activité du di-allate et du tri-allate 相似文献
A. fatua sown at depths of 5–15 cm was killed by di-allate or tri-allate. as were seedlings treated at the 15–2-leaf stage. Seedlings of spring wheat ( Triticum aestivum L.) survived rates of 24 oz/ac if the shoots were 1–3 cm long prior to exposure.
When di-allate at 16 oz/ac was mixed with a 5 cm layer of Regina heavy clay (wilting point 19–6%) slightly less than 15% soil moisture was required to give complete control of A.fatua. Further experiments indicated that a large percentage of A. fatua seedlings were killed by the action of di-allate vapour in the soil.
In other tests the activity of di-allate and tri-allate was reduced when the percentage of organic matter in the soil was increased by adding peat. This could explain why there is little damage to wheat sown in treated soil of high organic content while similar rates can cause extensive damage in soils of low organic content.
Under comparable conditions tri-allate persisted for a longer period in the soil than di-allate. Both chemicals exhibited a lag period after which their breakdown appeared to follow a first-order reaction. Differences in the period of persistence were attributed to a much longer lag period and a slightly slower rate of biological breakdown for tri-allate as compared to di-allate.
Facteurs affectant l'activité du di-allate et du tri-allate 相似文献
14.
DIRECT-DRILLING OF CEREALS AFTER USE OF PARAQUAT 总被引：1，自引：0，他引：1
Summary. Cereal crops were grown at Jealott's Hill in 1962 and 1963 without cultivations, following the use, before drilling, of paraquat to kill unwanted vegetation. This investigation was extended with a series of trials at outside centres. Three trials with winter wheat were drilled in the autumn of 1963, two into pasture and one into stubble. Three barley trials were drilled into stubble in spring 1964.
All the autumn trials and one spring trial compared direct-drilling with normal cultivations at two levels of nitrogen. The other two spring trials compared rates and times of application of paraquat without any plough comparison.
Individual trials showed significant yield differences between direct-drilling and ploughing, but there was no consistent advantage in favour of either technique.
Spraying in advance of drilling generally resulted in similar yields to spraying and drilling on the same day. Winter wheat drilled into pastures showed some retardation of spring growth when spraying and drilling had been carried out on the same day.
When averaged over times of application, yields after spraying paraquat at 2 lb/ac were significantly higher than after 1 lb/ac.
In the trials where two levels of nitrogen were included crops responded to an increase from 60 to 120 units nitrogen/ac as top dressing for winter wheat and from 60 to 90 units nitrogen/ac combine-drilled for spring barley; the response was not always significant.
Semis direct de céréales après application de paraquat 相似文献
All the autumn trials and one spring trial compared direct-drilling with normal cultivations at two levels of nitrogen. The other two spring trials compared rates and times of application of paraquat without any plough comparison.
Individual trials showed significant yield differences between direct-drilling and ploughing, but there was no consistent advantage in favour of either technique.
Spraying in advance of drilling generally resulted in similar yields to spraying and drilling on the same day. Winter wheat drilled into pastures showed some retardation of spring growth when spraying and drilling had been carried out on the same day.
When averaged over times of application, yields after spraying paraquat at 2 lb/ac were significantly higher than after 1 lb/ac.
In the trials where two levels of nitrogen were included crops responded to an increase from 60 to 120 units nitrogen/ac as top dressing for winter wheat and from 60 to 90 units nitrogen/ac combine-drilled for spring barley; the response was not always significant.
Semis direct de céréales après application de paraquat 相似文献
15.
Summary. Using autoradiographic techniques, the long-distance transport of 'ethylene'14 C-labelled diquat dibromide was studied. It was confirmed that a period of darkness after diquat application was necessary for reliable systemic action during a subsequent light exposure. Darkness was necessary in the region where the herbicide was applied, and then only to allow adequate penetration of diquat. This was its only role.
Desiccation following death, with the transfer of free water containing diquat to other leaves are the primary forces of long-distance transport; light is essential only for rapid toxic action and not directly for transport. Orthophosphate-32 P and urea-14 C applied topically with unlabelled diquat were distributed in the same pathway as the herbicide and not in the phloem. These results are discussed.
Nouvelles recherches sur l'influence de la lumière et de l'obscurité sur le transport à longue distance du diquat dans Lycopersicon esculentum Mill . 相似文献
Desiccation following death, with the transfer of free water containing diquat to other leaves are the primary forces of long-distance transport; light is essential only for rapid toxic action and not directly for transport. Orthophosphate-
Nouvelles recherches sur l'influence de la lumière et de l'obscurité sur le transport à longue distance du diquat dans Lycopersicon esculentum Mill . 相似文献
16.
The change in cell-membrane permeability as indicated by leakage of electrolytes from treated fronds of Lemna minor was the criterion used to detect the presence of diquat and paraquat in solution. The minimum herbicide concentrations that could be detected ranged from 1.8 and 1.7 μg/ml diquat and paraquat cation respectively after 3 h treatment to 0.00018 and 0.000017 μg/ml after 72 h. Paraquat was more active than diquat in all treatments. Increase in cell-membrane permeability occurred without the appearance of injury such as, chlorosis or bleaching of fronds. Light was necessary for these herbicides to alter cell-membrane permeability, though a little herbicidal activity could be detected after 48 h in the dark at concentrations above 0.17μg/ml. Un test biologique rapide et sensible pour la recherche du paraquat et du diquat dans l'eau Des modifications de la perméabilité de la membrane cellulaire, révélées par la déperdition d'électrolytes à partir de frondes de Lemna minor, ont été utilisées comme critères pour révéler la prèsence de diquat et de paraquat dans des solutions. Les concentrations minimales d'herbicides qui ont pu être décelées se sont situées entre 1,8 μg/ml et 1,7 μg/ml des cations diquat et paraquat respectivement, apres 3 heures de traitement, jusquà 0,00018 et 0,000017 μg/ml après 72 heures. Le paraquat s'est montré plus actif que le diquat dans tous les traitements. Un accroissement de la perméabilité cellulaire s'est produit sans qu'il soit apparu de dégâts tels que la chlorose ou le blanchissement des frondes. La lumière a été nécessaire pour que ces herbicides altèrent la perméabilité de la membrane cellulaire, bien qu'une faible activité herbicide ait pu être décelée après 48 heures à l'obscurité, à des concentrations supérieures à 0,17 μg/ml. Ein schneller und empindlicher Biotest für den Nachweis von Paraquat und Deiquat in Wasser Veränderungen in der Permeabilität der Zellmembran in Form des Austretens von Elektrolyten aus behandelten Wedeln von Lemna minor wurden als Kriterium für den Nachweis von Deiquat und Paraquat in wässeriger Lösung benutzt. Die geringsten Herbizidkonzentrationen, die festgestellt werden konnten, lagen nach 3 h nach der Applikation bei 1,8 und 1,7 μg/ml Deiquatbzw. Paraquat-Kation und nach 72 h bei 0,00018 und 0,000017 (μg/ml). In allen Behandlungen war Paraquat wirksamer als Deiquat. Der Anstieg in der Zellmembran-Per-meabilität war nichi mit äusseren Symptomen wie Chlorose oder Ausbleichen der Wedel verbunden. Für die Herbizidbedingte Veränderung der Zellmembran-Permeabilität war Licht notwendig, doch konnte auch eine geringfügige Herbizidwirkung nach einer 48-h-Dunkelperiode bei Konzenlrationen > 0,17 μg/ml festgestellt werden. 相似文献
17.
D. H. ROMNEY 《Weed Research》1964,4(1):24-30
Summary. Phytotoxic effects of eight herbicides on young coconuts were assessed by recording visual symptoms of injury and growth following treatment. The growth-regulators 2,4-D, 2,4,5-T and MCPB were lethal at the normal doses used for annual weed control. Dalapon at 5–9 lb/ac applied in 100 gal/ac of water caused yellowing and necrosis of the foliage, reduced growth, and sometimes killed the whole plant, while doses down to 2.2 lb/ac caused some fusion of the pinnae. Monuron at 3.2 and 6.4 lb/ac resulted in serious frond damage and reduced growth, and some frond injury occurred at 1–6 lb/ac. Diquat at 0.25–1.0 lb/ac and paraquat at 1.0–l.5 lb/ac caused extensive necrosis of existing fronds but there was no appreciable reduction in new growth. Amitrole produced considerable chlorosis both at 3.1 and G.3 lb/ac, but only the higher dose caused a reduction in growth.
Essai d'herbicides sur jeunes cocotiers 相似文献
Essai d'herbicides sur jeunes cocotiers 相似文献
18.
A. K. SETH 《Weed Research》1970,10(2):87-93
Summary. Paraquat-based treatments were evaluated for the control of Imperata cylindrica (L.) Beauv., a perennial grass with extensive rhizomes of great regenerative power. Single applications of 0–5 lb/ac paraquat gave good initial control, but regeneration was rapid. Increases up to 2–0 lb/ac had little effect on the duration of control, nor did the volume rate from 40 to 120 gal/ac. When an initial application of 05 lb/ac was followed by two further applications of 0–25 lb/ac, when the level of control had decreased to 50%, lasting control was obtained. Application of 6–8 lb/ac dalapon followed by 0–25 lb/ac paraquat also gave good control, comparable with that achieved by the conventional treatment of dalapon alone at 15–20 lb/ac. La lutte chimique contre Imperata cylindrica (L.) Beauv. en Malaisie Résumé. Des traitements utilisant le paraquat ont étè essayés pour lutter contre Imperata cylindrica (L.) Beauv., graminée pérenne avec des rhizomes importants qui manifestent un pouvoir de régénération élevé, Des applications uniques de paraquat à la dose 0,56 kg/ha ement un bon eifel initial mais la régéneration fut rapide. L'accroissement de la dose jusquà 2,2 kg/ha n'eut qu'une faible incidence sur la durée de l'action herbicide, l'augmentation du volume de traitement de 450 à 1350 1/ha ne provoqua pas non plus d'augmentation de I'efficacité. Une seule application de paraquat à 0,56 kg/ha, quand le niveau de I'efficacité eut décru jusquà 50%, suivie de deux applications supplémen-taires à 0,275 kg/ha, donna une efficacité plus durable. Des applications de dalapon de 6,7 à 9,0 kg/ha suivies de traitements au paraquat à 0,275 kg/ha donnèerent un résultat aussi bon que celui obtenu par les traitements habituels au dalapon seul, à la dose dc 16 à 22 kg/ha. Chemisehe Bekampfung von Imperata cylindrica (L.) Beauv. in Malaysia Zusammenfassung. Es erfolgten Untersuchungen zur Bekämpfung von Imperata cylindrica (L.) Beauv., einem mehrjährigen Gras mit einem ausgedehnten Rhizomsystem und starker Regenerationskraft, mit Paraquat, Einmalige Applikation von 0,56 kg/ha Paraquat hatte zwar eine gute Anfangswirkung, doch erfolgte rasche Regeneration. Eine Erhöhung bis auf 2,2 kg/ha war ebenso wie eine Änderung der Spritzbrühmenge von ca 450–1350 I/ha von geringem Einfluss auf die Nachhaltigkeit der Bekämpfungs-massnahmen. Eine einmalige Anwendung von 0,56 kg/ha Paraquat gefolgt von zwei weiteren Applikationen von 0,28 kg/ha, wenn die Regeneration ungelahr 50% erreicht hatte, ergab nachhaltige Wirkung. Behandlungen mit 6,7-9 kg/ha Dalapon gefolgt von 0,28 kg/ha Paraquat hatten ebenfalis eine gute Wirkung, die mit der einer konven-tionellen Behandlung mit 16,8-22 kg/ha Dalapon vergleiehbar war. 相似文献
19.
Effects of paraquat, activated aminoiriazole am) glyphosate on cellulose decomposition were studied in laboratory experiments. Herbicides were either incorporated in soil or sprayed onto cellulosic substrates which were incubated either on the surface of soil or buried. Paraquat applied directly to the substrates inhibited their decay hut not when applied to the soil. Aminotriazole. incorporated in soil at 500 ppm strongly suppressed decomposition of buried calico but effects varied with surface incubation. The only effects observed at 150 ppm were occasional stimulations of the decay of surface-incubated calico. Glyphosate applied either lo soil or substrate usually stimulated cellulose decay. Numbers of propagules of cellulolytic fungi were decreased by aminoiriazole and glyphosate applied to the soil and by glyphosate and paraquat applied to cellulose, but increased in soil treated with paraquat. In pure culture paraquat was the most, and aminoiriazole the least, toxic to the live test fungi. Numbers of cellulolytic bacteria were decreased in soil treated with paraquat but the other two herbicides either did not affect or stimulated this group. Effets du paraquat, de I'aminotriazole active et du glyphosate sur la décomposition de la cellulose. Les effets du paraquat, de I'aminotriazole activé et du glyphosate sur la décomposition de la cellulose ont étéétudiés dans des expériences de laboratoires. Les herbicides ont été appliqués de deux manières: incorporés dans le sol ou pulverises sur des substratscellulosiques, lesquelsonl été mis en incubation a deux niveaux; à la surface du sol et dans le sol. Le paraquat appliquè directement sur les substrats a empêché leur décomposition, mais non dans le cas ou ils ont été appliqués sur le sol. L'aminolriazo le incorporé a 500 ppm dans le sol a fortement relenti la decomposition du calicot enterre, mais les effets ont été variables pour l'incubation en surface, Les seuls effets observés à 150 ppm ont été des accélérations occasiormelles de la décomposition du calicol mis en incubation en surface. Le glyphosatc appliqué aussi bien au sol qu'au substrat, a généra temcnl aecélere la décomposition de la cellulose. Le nombre de propagules de champignons cellulolytiques a été diminué par l'aminolriazole et le glyphosale apportés par le sol et par le glyphosate el le paraquat appliqués sur la cellulose, mais il a augmenté dans le sol traiteau paraquat. En culture pure, le paraquat s'est révélér le plus toxique et l'aminotriazole le moins toxique dans cinq tests fungiques, Le nombre des bacléries cellulolytiques a été réduit dans le sol traité avec le paraquat, mais les deux autres herbi cides n'ont ni affecté ni slimulé ce groupe. Wirkungen von Paraquat. Aminotriazol und Glyphosate auf den Zelluloseabbau In Laborversuchen wurde die Wirkung von Paraquat, markiertem Aminotriazol und Glyphosate auf den Zelluloseabbau untersucht. Die Herbizide wurden sowohl in den Boden eingcarbeitet als auch auf Zelluioscsubsirate gesprtzt. welche entweder auf der Obernache des Bodens oder un Boden vergraben bebrütet wurden Paraquat direkt auf die Substrate gespritzt hemmte ihre Zersctzung, dies trat nicht ein bei der Behandlung des Bodens. Aminotriazol in einer Konzenlration von 500 ppm in Boden eingemischt, unterdrüekte sehr slark die Zersetzung von vergrabenem Baumwollsr off (Kaliko), jedoch schwanklen die Wirkungen bei der Obertlächenvariante. Die einzigen Wirkungen. die bei 150 ppm beobachtet wurden, war en gelegentliche Förderungen der Zersetzung bei oberflächlich bebrütetem Baumwollstoff (Kaliko). Glyphosate forderle im ailgemeinen die Zellulosezersetzung sowohl im Boden als auch auf dem Substral. Die Zahl der Sporen zellolytischer Pilze wrurde vermindert durch Aminotriazol und Glyphosate bei Bodenbehandlung und durch Glyphosale und Paraquat bei direkter Spritzung der Zellulose. Eine Zunahme war festzuslellen. bei Paraquat behandeltem Boden Auf 5 Reinkulturen von Testpilzen wirkte Paraquat am meisten, Aminotriazol am wenigslen toxisch. Die Zahl zelluloscabbauender Bakterién nahm bei Paraquat behandeltem Boden ab, Bei den beiden anderen Herbiziden war keine Wirkung festzustellen 相似文献
20.
Summary. Laboratory experiments were conducted to determine if paraquat had any effect on soil micro-organisms and consequently on soil fertility. Numbers of bacteria and moulds tended to increase with incubation time as residual paraquat decreased. Lag periods of 1–5 days were observed in the development of soil microflora and concomitant degradation of paraquat. Under controlled culture conditions, Aerobacter aerogenes, Agrobacterium tumefaciens, Pseudomonas fluorescens and Bacillus cereus were able to utilize paraquat as sole carbon and nitrogen sources in synthetic media. Paraquat at 0–25, 0–5, 2–5 and 25 ppm cation was added to four different soils to study changes in microbial activities concomitant with decreases in herbicide concentration. Analytical recoveries were correlated inversely with clay mineral content, cation-exchange capacity and organic matter. Mineralization of peptone nitrogen by amnnonification and nitrification was stimulated by 0–25 ppm; higher rates up to 25 ppm had little influence. A bimodal effect or growth inversion was observed in several instances, with increased microbial development at intermediate concentrations. Paraquat at recommended field rates appeared to have no appreciable influence on general microbial activities of importance to soil fertility. Interaction entre U paraquat et les microbes dans les sols 相似文献