bluuebunny/crossref_metadata_2025 huggingface dataset:
CONTROL OF SONCHUS ARVENSIS (L.) WITH CHEMICALS
Authors: VIDME T.
Published: July 2006

Summary. Pot experiments concerning the control of Sonchus arvensis with chemicals showed that the time of application of MCPA or 2,4‐D has a dominant influence on the results obtained. Foliage applications at late rosette to early bud stage gave considerably better effects than did earlier or later applications as assessed by the. weight of roots, this assessment being considered the most reliable for final effects. Increasing the rates from 1 to 3 kg/ha was of less significance than the time of application. A good wetting ability of the spray solution is also essential for an effective control of this weed, which has very waxy leaves. The addition of a wetting agent to aqueous solutions of various salts of 2,4‐D had a great and significant influence on the effects. This was not the case with 2,4‐D acid in Carbowax. When wetter was added, there was no difference in the effects of the sodium, ammonium and triethanolamine salts. The latter were also slightly more effective than MCPA. 2,4‐D‐ester was much more effective than MCPA by foliage application. When the chemicals were applied to the roots through sub‐irrigation pipes, however, MCPA was at least as effective as 2,4‐D‐ester. The maximum effect by this method of application was obtained at a somewhat later stage of development than by foliage application. By foliage application of MCPA and dinoseb or DNOC at various rates used alone or in mixture, an antagonism between the growth regulator and the contact herbicides was demonstrated as regards the reduction in root weight of S. arvensis. The scorching effects of dinitro compounds were, on the contrary, increased when applied in combination with MCPA. Amitrole at rates of 5, 7.5 and 10 kg/ha applied at late rosette stage gave a complete kill of S. arvensis.

La destruction du Sonchus arvensis L. à l'aide de produits chimiques
CHEMICAL WEED CONTROL IN SPRING‐SOWN BROAD BEANS
Authors: ROBERTS H. A. , WILSON B. J.
Published: July 2006

Summary. During the period 1956‐61, twelve replicated field experiments were conducted to determine the response of spring‐sown broad beans (Vicia faba L.) and annual weeds to various pre‐ and post‐emergence herbicides. On a sandy loam, the best results were given by pre‐emergence applications of simazine 0.75 lb/ac, trietazine 1.5 lb/ac, chlorpropham 1 lb+diuron 0.2 lb/ac or dinoseb‐amine 4 lb/ac. Amiben proved insufficiently selective, while chlorpropham+fenuron caused greater crop injury than the corresponding mixture with diuron. Post‐emergence application of dinoseb‐amine was less satisfactory than the best of the pre‐emergence treatments.

Le désherbage chimique des fèves semées au printemps
THE EFFECTS OF MALEIC HYDRAZIDE AND 2,4‐DICHLOROPHENOXYACETIC ACID ON ROADSIDE VEGETATION
Authors: YEMM E. W. , WILLIS A. J.
Published: July 2006

Summary. Observations have been made on the effects of maleic hydrazide (MH) and 2,4‐dichlorophenoxyacetic acid (2,4‐D), used singly or as a combined spray, on the vegetation of roadside verges, over a period of 3‐4 years (1958‐61). Each year, replicate plots were sprayed in spring, and assessments of growth and floristic composition of the vegetation, which was dominated by grasses, were usually made on three occasions. Treatment with MH, used singly, resulted in a general suppression of growth and flowering, particularly of the grasses. Well‐marked changes in the composition of the sward were attributable to MH, notably the decline of tufted forms, e.g. Arrhenatherum elatius, Dactylis glomerata, and the rise to dominance of the rhizomatous grasses. These changes were associated with a progressive increase of some dicotyledonous plants, although this was effectively prevented by the combined spray of MH and 2,4‐D. Two of the commonest weeds, Anthriscus sylvestris and Heracleum sphondylium, were almost eliminated from plots treated with this combined spray for 3 successive years; a low sward, fairly free from dicotyledons and dominated by Poa rather than Festuca, usually resulted. Treatment with 2,4‐D alone, had relatively little effect on growth, flowering and proportion of the different grasses, but there was a reduction in the weed population.

Les effets de l'hydrazide maléique et de l'acide 2,4‐dichlorophénoxyacétique sur la végetation au bord d'une route
PRELIMINARY OBSERVATIONS ON THE BREAKDOWN OF 3‐AMINO‐l,2,4‐TRIAZOLE IN SOIL
Authors: RIEPMA P.
Published: July 2006

Summary. The breakdown of amitrole has been studied on different soil types and at two temperatures. It is shown by use of soil sterilization and of microbiological toxicants, that amitrole is broken down microbiologically. Increase in soil organic matter and in temperature up to 30° C both increase the rapidity of breakdown.

Premières observations sur la décomposition du 3‐amino‐1,2,4‐triazole dans le sol
THE EFFECT OF 4,6‐DINITRO‐O‐CRESOL* (DNOC) ON GROWTH, DEVELOPMENT AND YIELD OF WINTER RYE (SECALE CEREALE L.)
Authors: BRUINSMA J.
Published: July 2006

Summary. The spraying with DNOC as a herbicide in a young crop of winter rye results in an increased grain yield, even in weed‐free trials. In order to trace the sequence of reactions by which treatment in winter affects the yield next summer, growth, development and yield of treated and untreated plants were examined in a single weed‐free experiment which included the study of several seed rates.

As a result of the DNOC treatment, vegetative growth was retarded at first, but later the treated plants recovered and surpassed the control plants in fresh and dry weight. Since their dry matter percentage was somewhat lower and their nitrogen content a little higher, the crop appeared both more vigorous and more youthful. Leaf blade area and chlorophyll content of leaves and culms were increased and chlorophyll breakdown at ripening was delayed.

No effect could be observed on the rate of development of the young spike, but heading, flowering and ripening were retarded.

Yield increase on the DNOC‐treated plots was 10% on an average. The analysis reveals that on these plots 3% more culms were formed, each of which bore 5% more kernels; the average kernel weight was unaffected. The increase in ear density can be ascribed to the more luxuriant vegetative growth, while the kernel weight per car is correlated with the nitrogen content of the culm.

It is concluded that the yield increase is due to a stronger vegetative growth together with a prolonged period of generative development.

Effets d'un traitement au DNOC sur la croissance, le développement el le rendement d'un seigle d'hiver
STUDIES ON THE TRANSLOCATION IN AGROPYRON REPENS OF 14C‐LABELLED 2,2‐DICHLOROPROPIONIC ACID
Authors: McINTYRK G. I.
Published: July 2006

Summary. Previous findings suggested that the translocation in Agropyron repens of 2,2‐dichloropropionic acid (dalapon) may be considerably affected by the transpiration rate. This relationship has been studied further in the present investigation using 14C‐labelled material and autoradiography.

It was found that when dalapon was applied to the leaves and the treated plants were placed in darkness a reduction in the transpiration rate of ca. 90% was associated with a marked increase in the amount of dalapon translocation into the roots and tillers. The evidence provided by the autoradiographs was confirmed by a quantitative assay of the 14C present in the roots. It was also found, however, that translocation was not appreciably affected either by a 50% reduction in the light intensity or when the transpiration rate was reduced by placing the plaints under conditions of high humidity in the light or by the application of white petroleum jelly to the leaves. An alternative hypothesis, namely that the effect of darkness on the movement of the herbicide might be due to changes induced in the normal pattern of assimilate translocation was also investigated but was not supported by the results obtained. Further experimentss, in which various parts of the treated shoot were placed in the dark, suggested that the effect of darkness on the translocation of dalapon is exerted primarily on the treated leaf itself.

Etudes sur to migration dans Agropyron repens de l'acide 2,2‐dichloropropionique marqué avec 14C
1‐PHENYL‐4‐AMINO‐5‐CHLOR‐PYRIDAZON‐6* (PCA) ALS EIN NEUES RüBENHERBIZID
Authors: FISCHER A.
Published: July 2006

Zusammenfassung. Bei unseren Arbeiten zur Entwicklung neuer Rübenherbizide fiel die Sloffgruppe der Phenylpyridazone als besonders wirksam auf. Es wurden bisher über 500 Pyridazon‐Dcrivate geprüft. Bei diesen Untersuchungen zeigte l‐Phenyl‐4‐amino‐5‐chlor‐pyridazon‐G (PCA) die besten herbiziden Eigenschaften. PCA besitzt sowohl im Vor‐ als auch im Nachauflauf‐Verfahren bei Aufwandmengen von 1‐3 kg/ha Wirkstoff eine genügende Selektivität gegenüber Zucker‐ und Futterrüben. Die Nachwirkungszeit von PCA in lehmigem Sandboden ist kürzer als diejenige von OMU, CMU und Simazin. Nach einer Behandlung mit 2 kg/ha PCA kann eine Neueinsaat nach 8‐10 Wochen ohne Gefahr für die Kulturpflanzen erfolgen. Die herbizide Wirkung von PCA umfasst die meisten in Rübenkulturen vorkommenden Samenunkräuter. Schwierig bekämpfbar sind Avena fatua und einzelne Vicia‐Arten. überhaupt nicht bekämpfbar sind sämtliche Wurzelunkräuter. PCA ermöglicht eine Unkrautbekämpfung in Rüben ohne Rücksicht auf deren Entwicklungszustand. Günstiger Spritztermin: Keimblattstadium der Unkräuter. Mögliche Rübensch aUden sind abhängig vom Wetter zur Zeit der Spritzung. Am günstigsten sind windstilles Wetter, bedeckt Himmel, Temperaturen bis etwa 22°C sowie eine relative Luftfeuchtigkeit von 40‐70%. Die Unkrautwirkung von PCA wird durch geringen Zusatz von OMU im Vorauflauf‐Verfahren eindeutig gesteigert. Die Bekämpfung grösserer Unkräuter (2.‐4. Laubblattstadium) im Nachauflauf‐Verfahren mit 1‐3 kg/ha PCA kann durch Zusatz von 100‐150 kg/ha NaNO3 verbessert werden.

5‐amino‐4‐chloro‐2,3‐dihydro‐3‐oxo‐1‐phenylpyridazone as a new herbicide for sugar beet
UNTERSUCHUNGEN üBER öKOLOGIE UND BEKäMPFUNGSMöGLIGHKEITEN DES HUFLATTICHS (TUSSILAGO FARFARA L.)*
Authors: LEUCHS F.
Published: July 2006

Summary. The effect of herbicides on coltsfoot (Tussilago farfara L.) varies according to the plant's constitution resulting from different environments. 4‐CPA‐ester had the best effect of all the auxin‐type herbicides. The application of 4‐CPA in cereals is not possible because of its phytotoxicity, but this chemical could be promising for the control of coltsfoot in grassland. Fenoprop (2,4,5‐TP) is somewhat less effective but cereals, especially wheat (Triticum setivum L.) and oats (Avena sativa L.), are more tolerant. All the other auxin‐type herbicides, including mecoprop (CMPP) and 2,4,5‐T were unsatisfactory. Control of coltsfoot after harvesting the cereals was most satisfactory with amitrole (7.5‐10 kg/ha in one application or two applications of 4 and 6 kg within 3‐4 days). Shallow ploughing 4‐6 weeks after spraying increased the effect as did the addition of Nad (10‐20 kg/ha) to the spray‐fluid. Good results with amitrole can be obtained only when the plants are growing vigorously and have a sufficient amount of large and healthy leaves at che time of application, not damaged at harvest and without fungus infection. There should be dry weather 2‐3 days prior to the application. The regrowth in the following spring is usually so weak that it cannot compete with the crop plants. The soil should be cultivated immediately after harvest, so that the still living remains of coltsfoot plants can also be killed and re‐establishment prevented. It is advisable to plant root crops after the chemical control of coltsfoot, so that the weak regrowth can be killed by the normal cultivation practices of these crops. The residual effect of amitrole in the soil can vary widely. Under conditions in the Rhine Valley the residues are partially broken down biologically, partially leached during autumn (and winter), so that the following summer crop can be grown without risk.
THE EFFECTS OF SUB‐LETHAL DOSES OF MCPA ON THE MORPHOLOGY AND YIELD OF VEGETABLE CROPS
Authors: WAY J. M.
Published: July 2006

Summary. The effect of sub‐lethal doses of MCPA‐sodium on the morphology, growth and yield of carrots and parsnips was studied in twenty replicated field experiments. Slight epinasty was produced in carrots by doses as low as 0.002 lb/ac a.e., but formative effects were not usually seen below 0.01 lb/ac. Crop weight was only reduced by doses greater than 0.1 lb/ac, but abnormalities rendered a proportion of the roots unmarketable at doses below 0.05 lb/ac. Small plants were sometimes killed by 0.3 lb/ac, but larger plants survived treatment with up to 0.5 lb/ac. Tests on carrots which were unmarketable on grounds of appearance failed to reveal any effect of MCPA on flavour, sweetness or texture of the roots. The effects of MCPA on parsnips were similar to those on carrots, but the expression of injury symptoms was generally less marked.

Les effets de doses sub‐létales de MCPA sur la morphologie et le rendement des cultures légumières III. Carottes et panais
STUDIES OF THE RESPONSE OF PLANTS TO ROOT‐APPLIED HERBICIDES
Authors: LYNDSAY RUTH V. , HARTLEY G. S.
Published: July 2006

Summary. Peas, barley and linseed were grown in water‐cuture. Roots were divided into two portions and contained in separate vessels. The effect of herbicides applied to one‐third of the roots was compared with their effect when applied to the whole root system.

Propham, chlorpropham, atratone and 2,3,6‐TBA killed the plant whether application was to one‐third or all of the roots. Roots in direct contact with propham, chlorpropham and 2,3,6‐TBA were deformed or killed, while roots in uncontaminated solution remained healthy. The effect of atratone and high concentrations of chlorpropham on a portion of the roots was transmitted to roots not in the toxic solution.

Certain concentrations of MCPA and DNOC applied to the whole root system killed the plant while three times the concentration to one‐third of the roots caused local damage but had little effect on the plant as a whole. Sufficient herbicide may be taken up by one‐ third of the roots from high concentrations to kill the whole plant.

TGA gave variable results with respect to the health of the aerial portion of the plant but had no obvious direct effect on root growth.

Propham, chlorpropham, atratone and 2,3,6‐TBA reduced transpiration rates whether applied to part or whole root systems. MCPA and DNOC prevented water uptake by roots with which they Were in direct contact.

Etudes sur les réactions de certaines plantes à des herbicides appliqués aux racines I. Effet d'une application localisée
UNTERSUCHUNGEN ÜBER DEN EINFLUSS DER SAMEN‐ UND BODENMIKROFLORA AUF DIE LEBENS DAUER DER SPELZFRÜCHTE DES FLUGHAFERS (AVENA FATUA L.)
Authors: KIEWNICK L.
Published: July 2006

Zusammenfassung. Die Spelzfrüchte (‘Samen’) des Flughafers (Avena fatua L.) werden von einer Vielzahl von Organismen besiedelt, deren Anzahl vom Kulturpflanzenbestand und von den jeweils herrschenden Witterungsbedingungen während der Reife abhängt. Zusammenhänge zwischen Höhe der Niederschläge, Mikroorganismenbesatz an den Früchten und der Keimpotenz konnten ermittelt werden. Insgesamt wurden zweiundfünfzig Pilzarten von den Flughaferfrüchten isoliert. Davon gehören zwei zu den Phycomyceten, fünf zu den Ascomyceten und fünfundvierzig zu den Fungi imperfecti. In Infektionsversuchen haben sich Phoma hibernica, Cephalosporium gramineum, Stemphylium consortiale, Helminthosporium gramineum, Fusarium culmorum, Fusarium solani und Fusarium scirpi als pathogen gegenüber den im Boden lagernden Samen erwiesen. Von den Samenpilzen war Fusarium culmorum ursächlich an der Ausbildung tauber Samen beteiligt. Bei Lagerung der Samen unter hoher Luftfeuchtigkeit und gleichzeitiger Einwirkung der Mikroflora konnte nach 3 Monaten ein merklicher (34% bei 100% r.Dampfspannung) und nach 6 Monaten ein starker (51% bei 100% r.Dampfspannung) Abfall der Keimfähigkeit beobachtet werden.

Experiments on the influence of seedborne and soilborne microflora on the viability of wild oat seeds (Avena fatua L.)

I. The occurrence, specific composition and properties of microorganisms on wild oat seeds
UNTERSUCHUNGEN ÜBER DEN EINFLUSS DER SAMEN‐ UND BODENMIKROFLORA AUF DIE LEBENSDAUER DER SPELZFRÜCHTE DES FLUGHAFERS (AVENA FATUA L.)
Authors: KIEWNICK L.
Published: July 2006

Zusammenfassung. Versuche mit oberflächensterilen und unbehandelten Flughaferfrüchten, die im Freiland in gedämpfte und normale Ackererde ausgesät wurden, zeigten, dass die Mikroflora massgeblich die Lebensdauer der Samen im Boden beeinflusst. Pilze und Bakterien der Spermatosphäre haben ein Minimum im Winter, ein Maximum im Frühjahr, einen Rückgang im Sommer und einen Anstieg im Herbst. Dementsprechend kann sich in der Zeit der Maxima die starke Aktivität der Pilze negativ auf die ruhenden Samen auswirken. Es wird daraufhingewiesen, dass die Unkrautsamen ein Reservoir für Bodenpilze, Saprophyten und Parasiten darstellen und im Kreisiauf dieser Pilze eine bedeutende Rolle spielen.

Es konnte gezeigt werden, dass die Bodenfeuchtigkeit Samen und Mikroflora beeinflusst. Die Pilze sind bei einer Wasserabsättigung von 50% am stärksten aggressiv. Ein hoher Wassergehalt des Bodens kann eine zweite, im gleichen Jahr nicht mehr reversible Keimruhe induzieren, langanhaltende Nässe führt zur Autolyse der Samen.

Flughafer keimt am besten, wenn die Körner mit einem Wassergehalt von 14,6 bis 17,0% in den Boden gebracht werden. Höhere Feuchtigkeitsmengen im Samen führen zur zweilen Keimruhe, dir für den Angriff der Mikroorganismen günstig ist.

Kompost und die geprüften Sandböden fördern die Keimung der Samen, stimulieren aber auch die Mikroorganismen. Es kann zu einer etwa 15% höheren Zerstörung der Samen gegenüber Lehmböden kommen.

Es werden die Aussichten für eine praktische Anwendung der gewonnenen Kenntnisse diskutiert.

Experiments on the influence ofseedborne and soilborne muroflora on the viability of wild oat suds (Avena fatua L.)

II. Experiments on the influence of microflora on the viability of seeds in the soil
SELECTIVE HERBICIDAL CONTROL OF BARLEY GRASS IN PASTURE AND LUCERNE
Authors: CUTHBERTSON E. G.
Published: July 2006

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
A FIELD STUDY OF THE FACTORS AFFECTING THE HERBICIDAL ACTIVITY OF IOXYNIL AND BROMOXYNIL AND THEIR TOLERANCE BY CEREALS
Authors: TERRY H. J. , WILSON C. W.
Published: July 2006

Summary. The herbicidal activity and the tolerance of winter and spring cereals to ioxynil (4‐hydroxy‐3,5‐diiodobenzonitrile)and bromoxynil(3,5‐dibromo‐4‐hydroxybenzonitrile) as alkali metal and ammonium salts, have been determined in field experiments. Both compounds controlled most of the important weeds of cereals at doses between 3 and 8 oz a.i./ac. In seedling grass crops, where weeds were influenced less by crop competition, the effective dose range was 6–8 oz/ac. Some species normally resistant to the phenoxyalkanoic acid herbicides, including Stellaria media, Tripleurospermum marilimum and some Polygonum spp. were controlled by these herbicides. Ioxynil was generally more active than its dibromo analogue, particularly against Stellaria media. The activity of both compounds was improved by the addition of a wetting agent (0–02% sodium dinonyl sulphosuccinate) but activity was not influenced by changes in volume rate over the range 18–65 gal/ac. Perennial weeds were not affected by the doses needed for the control of annual weeds and rates of 16 oz/ac and above were necessary for the control of Cirsium arvense and Sonchus arvensis.

The factors most likely to affect cereal tolerance are growth stage of crop and the addition of wetter to the spray solution. Neither ioxynil nor bromoxynil significantly affected grain yields when applied to spring and winter wheat, spring barley and oats at two to four times the rate necessary for weed control. On a total of five varieties of spring wheat and six varieties each of spring barley and oats applications of both compounds at doses up to 32 oz/ac caused only temporary and superficial leaf scorch. In only two out of twenty‐five experiments was there more than slight scorch at doses below 16 oz/ac and these two cases do not significantly detract from the evidence of the high crop safety margin of these compounds.

Étude en plein champ des facteurs influençant l'activité herbicide de l'ioxynil et da bromoxynil et la tolérance des céréales à ces deux herbicides
THE REACTION OF WHEAT TO 2,4‐D ETHYL ESTER APPLIED IN DIFFERENT DILUENTS
Authors: MEADLY G. R. W.
Published: July 2006

Summary. In experiments at two sites in Western Australia, 2,4‐D ethyl ester was applied to Gabo wheat at the early tillering, advanced tillering and boot stages. A standard dose of 6 oz/ac a.e. was sprayed in diesel oil (4 pints/ac), water (4 pints/ac) and water (8 gal/ac), and half of each plot received a double application, to give twice the dose and twice the volume. The weed populations were negligible and differences obtained were attributable to the direct effects of the treatments on the wheat.

The most satisfactory treatment was 6 oz/ac applied in 8 gal/ac water at the early tillering stage. Contrary to previous evidence, application at the advanced tillering stage resulted in yield reduction, and it is supposed that the reaction of the wheat was affected by insufficient soil moisture during the later stages of growth. Application in 4 pints/ac water gave lower yields than application in 8 gal/ac, while with 4 pints/ac oil, yields were rather less than with 4 pints/ac water. Although there were some statistically significant effects on the germination and unit weight of the grain, these were not considered to be of practical importance.

Réaction du bléà l'ester éthylique du 2,4‐D appliqué dans divers diluants
A SMALL‐SCALE VARIABLE DOSAGE (LOGARITHMIC) SPRAYER*
Authors: CLARKE G. S. , ROSS A. A.
Published: July 2006

Summary. A small‐plot logarithmic sprayer, similar to that described by Cialone & Bayer (1962) but using containers more easily obtainable, and operating frorn a compressed‐air source, has been designed. Its main properties are portability, ease of operating and cleaning, and low cost, both initially and in future maintenance. It is of considerable value in difficult terrain, or when only small samples of chemical are available.

No mechanical agitation has been provided. It has been found that even with wettable powder suspensions, the hydraulic force of the diluent entering the concentrate bottle is sufficient to provide adequate agitation when using bottles no larger than 200 ml.

Replacement bottles are readily available, almost all over the world. They are of the type sold containing proprietary beverages under pressure, the essential feature being the crown‐cap.

Theoretical and actual dosage curves are very similar, and the machine has proved very useful for investigating dosage response characteristics of herbicides over the past season.

Un pulvérisateur à dosage variable (logarithimique) pour petites parcelles
WEEDS OF TOMATO AND CORN FIELDS IN TWO REGIONS OF ONTARIO
Authors: ALEX J. F.
Published: July 2006

Summary. Amaranthus retroflexus, Chenopodium album, Ambrosia artemisiifolia, Setaria glauca, S. viridis and Echinochloa crusgalli were the most widespread and abundant of the 103 weed species found in eighty‐eight fields of tomatoes (Lycopersicon esculentum) and sweet corn (Zea mays) surveyed in Prince Edward County and in Essex and Kent Counties during 1960 and 1961. None of the important weeds in either crop occurred exclusively in that crop. Differences in weed floras were greater between regions than between crops. Abutilon theophrasti, Euphorbia maculata, Apocynum cannabinum var. suksdorfii and Physalis virginiana var. subglabrata, important weeds in both crops in Essex and Kent, were not found in any surveyed field in Prince Edward County. Average numbers of weed species per field were 15.7 in Prince Edward County and 12.9 in Essex and Kent. Small dense infestations of Fumaria officinalis and Salvia reflexa, rare weeds in Canada, were discovered in Prince Edward County.

Mauvaises herbes des cultures de tomates et du maïs dans deux régions de l'Ontario
STUDIES ON WEED SPECIES OF THE GENUS POLYGONUM L.
Authors: HAMMERTON J. L.
Published: July 2006

Summary. Seeds of Polygonam persiaria were collected from seven localities during 1962. In 1963 plants of these seven populations were grown in the field and sampled at regular intervals over the period 21st June to 13th August. At all samplings there were differences between populations in total dry weight, in leaf area index and in total nitrogen content, and populations also differed in the date of flowering. The populations also differed significantly in relative growth rate, leaf area ratio, net assimilation rate and relative nitrogen absorption rate. The variations in net assimilation rate did not appear to be closely associated with variations in leaf area index. Certain growth attributes were correlated with the latitude of origin, and it is tentatively suggested that the populations may represent genetically distinct latitudinal ecotypes.

Études sur des espèces de mauvaises herbes du genre Polygonum L.
OBSERVATIONS ON THE RELATIONSHIP BETWEEN THE ADSORPTION OF DIURON AND THE NATURE OF THE ADSORBENT
Authors: HANCE R. J.
Published: July 2006

Summary. A series of adsorption experiments was carried out in order to determine if there was significant competition for adsorption sites between diuron and water. Adsorption of diuron was much lower on hydrophilic materials such as cellulose, chitin, aluminium oxide and a soil mineral fraction than on the less hydrophilic ion exchange resins, lignin, carbon and a soil organic fraction. Methylation with methanolic HCL or diazomethane increased adsorption by the soil organic material, but methylation with dimethyl sulphate did not.

The soil mineral fraction adsorbed considerably more diuron from petroleum spirit solution than from aqueous solution, but the organic matter preparation adsorbed more from aqueous than from petroleum solution.

It was concluded that there is competition between water and diuron for adsorption sites and that diuron is a more effective competitor at soil organic matter surfaces than at soil mineral matter surfaces.

Observations sur la relation entre l'adsorption du diuron el la nature de l'adsorbant
STUDIES ON OXALIS PES‐CAPRAE L. IN AUSTRALIA
Authors: MICHAEL P. W.
Published: July 2006

Summary. The widespread pentaploid variety of the important weed, Oxalis pes‐caprae was harvested eight times throughout its life cycle. Dry weight and oxalate (acid‐soluble and water‐soluble analyses were made on all parts of the plant at each harvest.

From the dry weight data obtained, attention is drawn to three stages during the growth of the plant — namely, the stage of old bulb exhaustion, the time when flowers and new bulbs begin to appear and the onset of senescence. Corresponding with these stages marked changes in oxalate metabolism and/or transport are observed.

It is proposed that the stage of old bulb exhaustion would be the most promising at which lo attempt control of the weed by cultivation.

Recherches sur Oxalis pes‐Caprae L. en Australie. I. Études quantitatives de l'acide oxalique durant le cycle vital de la variété pentaploide
THE EFFECT OF DISODIUM METHYLARSONATE, DALAPON, AMITROLE‐T AND PARAQUAT ON AXONOPUS COMPRESSUS, OTTOCHLOA NO DOSA AND PASPALUM CONJUGATUM
Authors: RIEPMA P.
Published: July 2006

Summary. The doses required to give 90% control of three weed species have been estimated at different intervals after spraying for four herbicides: amitrole‐T, dalapon‐sodium, disodium mcthylarsonate (DMA) and paraquat. Using the point quadrat method, both first and total contact data showed Ottochloa nodosa, to be more tolerant to the herbicides than Paspalum conjugatum, which in turn was more tolerant than Axonopus compressus. Ottachloa nodosa was most susceptible to paraquat up to 6 weeks after spraying, but thereafter dalapon was more effective than either paraquat, amitrolc‐T or DMA. For Paspalum conjugatum first contact data showed that paraquat was more effective than amitrole‐T, particularly in the first 10–11 weeks after spraying, and that both were more effective than DMA and dalapon; total contact data showed that paraquat and DMA were the most effective chemicals for up to 6 weeks after spraying but that thereafter amitrole‐T gave best results. Paraquat was the most effective herbicide against Axonopus compressus, while dalapon was more effective than amitrole‐T or DMA.
EFFECT OF TEMPERATURE ON THE ACTIVITY AND PERSISTENCE OF AMITROLE AND 2,4‐D
Authors: MUZIK T. J.
Published: July 2006

Summary. One leaf of each of several tomato plants 5–6 weeks old maintained at 55, 70 or 85° F was dipped in 0.05 M amitrole or 0.005 M 2,4‐D solution. The treated leaf was removed 1 week later. Scions taken from untreated plants were grafted to the treated plants at intervals up to 4 months after treatment.

Amitrole‐treated plants maintained at 55° F were killed within 1 month but those at 70 and 85° F recovered.

Plants treated with 2,4‐D showed typical symptoms when maintained at 70 and 85° F but no symptoms at 55° F. Scions grafted on plants maintained at 55, 70 and 85° F for 60 days after 2,4‐D treatments exhibited typical symptoms. Grafts made more than 60 days following the 2,4‐D application did not exhibit symptoms except a slight malformation on the plants held at 55° F.

New growth on the scions grafted up to 103 days after amitrole treatment on plants which had been maintained at 70 and 85° F exhibited typical amitrole symptoms (i.e. white foliage) but scions grafted after this lime did not. New shoots developing from buds on the treated plants also produced green growth 115 days after treatment but produced white foliage prior to that time.

Effet de la température sur l'activi'ité et la persistance de l'aminotriazole et du 2,4‐D
A PRELIMINARY INVESTIGATION OF THE PENETRATION AND TRANSLOCATION OF 2,4,5‐T IN SOME TROPICAL TREES
Authors: SUNDARAM ALAM
Published: July 2006

Summary The relative mobility of 14C‐labelled 2,4,5‐T in the trunks of four different tree species was tested in dry and wet seasons, with the intention of observing the difference in translocation pattern between the susceptible (Piptadeniastrum africanum, Celtis mildbraedii) and the tolerant (Xylopia quintasii, Ricinodendron heudelotii) species, Nine trees were analysed altogether. There was a consistent pattern of adsorption and retention of the arboricide by the phloem of the four sensitive trees and downward movement of the material was marked, but in the five resistant trees the chemical was distributed upward to a greater extent in the transpiration stream. Thus in the susceptible species where there is more phloem movement the chcmical is least mobile, whereas in the tolerant ones where the chemical moves in the xylem, it is most mobile. Both types of investigation (longitudinal and radial) indicate that the killing action in the sensitive species is due to the retention of the chemical by the phloem, and that its failure to kill the tolerant trees is due to the upward movement in the transpiration stream via the xylem.
THE ABILITY OF PARAQUAT, DALAPON AND AMITROLE‐T TO KILL AN AGROSTIS/LOLIUM PASTURE IN JULY, OCTOBER AND APRIL
Authors: ALLEN G. P.
Published: July 2006

Summary. Paraquat, dalapon and amitrole‐T were compared in their ability to kill a long‐established Agrostis/Lolium pasture in late July, late October and early April. Paraquat at 0.75, 1.5 and 3.0 lb/ac and dalapon at 10.6 and 15.0 lb/ac destroyed the sward most successfully but dalapon was not efficient at the April spraying. Amitrole‐T at 4.0 lb/ac had the ability to cause the sward severe chlorosis and to kill most broadleaved species but failed to achieve a substantial kill of grass at the three dates. Paraquat was judged the most efficient chemical being non‐residual and extremely rapid in action at all dates of application. Changes in botanical composition following chemical treatment are described. It is suggested that the composition of regrowth may be decided by choice of chemical and, in addition, influenced by the lime of application. Considerable reductions were achieved in the amount of Agrostis stolonifera recolonizing the plots after July application of all three chemicals but the autumn and spring treatments resulted in strong re‐establishment by this species. A substantial increase of Lolium perenne resulted from July applications and this was most marked following the application of 5 lb/ac dalapon.
RELATION BETWEEN STRUCTURE AND HERBICIDAL ACTIVITY OF SUBSTITUTED BENZONITRILES
Authors: KOOPMAN H. , DAAMS J.
Published: July 2006

Summary. The herbicidal activity of substituted benzonitriles was determined by a number of tests. This activity was compared with the structure of the molecules. It was found experimentally that benzonitriles, substituted at the 2 and 6 positions by halogen or methyl, had the highest activity. Some 2,6‐dichloro‐1‐substituted benzene derivatives showed a herbicidal activity, comparable with that of 2,6‐dichlorobenzonilrile. These compounds possessed a group which could be converted into a nitrilc group.

La relation entre la structure ft l'activité herbicide des benzonitril‐es substitués
THE TRANSLOCATION AND DISTRIBUTION OF THREE LABELLED HERBICIDES IN PASPALUM DISTICHUM L.
Authors: SMITH L. W. , DAVIES P. J.
Published: July 2006

Summary Plants of Paspalum distichum L. with two stolons growing over water were treated separately with the sodium salt of 2,2‐dichloropropionic acid‐36C1 (dalapon), 3‐amino‐1,2,4‐triazole‐14C (amitrole) and 1,1′‐dimethyl‐4,4′‐dipyridylium dichloride‐14C (paraquat) at four different situations on one stolon. Autoradiographs showed that both the amitrole and dalapon label accumulated in the apices of the treated stolons and in some of the young shoots growing from the base of the plant. The 14C from the paraquat label showed predominantly xylem translocating with no apical accumulation and little basal translocation. The results indicate that young basal shoots rely to some extent on assimilates from the mature stolons but that there is little transport between mature stolons.

La migration et la distribution de trois Herbicides marqués dans Paspalum distichum L.
THE CONTROL OF WEEDS IN TEA BY HERBICIDES IN MAURITIUS
Authors: ROCHECOUSTE E. , PILOT J.
Published: July 2006

Summary. Weed control experiments carried out in tea plantations showed that diuron at doses 2·4, 3·2 and 4·8 lb/ac a.i. resulted in better and more persistent weed control than siamazine.

Shoot absorption experiments carried out on three tea jats, dark, medium and light, showed that the tea jats differed in their tolerance to both diuron and simazine, the light one being the most susceptible.

A difference IN the expression of phytotoxic effects between leaf and root absorption was observed for diuron only. At equivalent doses, 2‐year‐old plants were in general more susceptible to diuron than to simazine.

Diuron and simazine used alone at 2·4, 3·2 and 4·8 lb/ac a.i. or with addition of sodium chlorate at 6 lb/ac to improve the kill of emerged weeds, did not affect yield of either pruned unpruned 6‐year‐oId tea. Dalapon, on the other hand, at 6 lb/ac significantly reduced the yield of unpruned tea but not of pruned lea.

Le désherbage chimique du théè l'lle Maurice
FACTORS AFFECTING PERSISTENCE AND INACTIVATION OF DIQUAT AND PARAQUAT
Authors: COATS G. E. , FUNDERBURK H. H. , LAWRENCE J. M. , DAVIS D. E.
Published: July 2006

Summary. The adsorption of diquat cation was found to be 0.3, 2.0–2.5 and 80–100 mg/g on a sandy loam soil, Grade Hydrite 10 Georgia kaolinite and National Standard Bentonite, respectively. Bentonite (113 lb/surface ac) applied to plastic pools previously treated with 1 ppm paraquat reduced the concentration of paraquat to less than 0–05 ppm within 24 hr of application. Only bentonite appeared to hold either diquat or paraquat in a form unavailable to wheat. Appreciable uptake by wheat from soil treated with diquat or paraquat (16 lb/ac pre‐emergence) occurred only in soil or sand in which the herbicide leached below the 05 in. zone. A 12 hr dark period following foliage application did not appear to enhance movement of either herbicide in wheat. Loss of radioactivity was observed when diquat or paraquat was exposed to ultraviolet light (2537 Å).

Facteurs agissant sur la persistence et l'inactivation du diquat et du paraquat
EXPERIMENTS WITH GRANULES OF DICHLOBENIL UNDER GLASSHOUSE CONDITIONS
Authors: HOROWITZ M.
Published: July 2006

Summary. Experiments with granular dichlobenil have been carried out under glasshouse conditions, in order to estimate the area of contamination near the surface and the leaching beneath by the toxicant from individual granules. Special techniques using a restricted range of granule size and ryegrass as indicator plant have been developed.

The area of contamination produced by grouping several granules together or by granules containing different concentrations of toxicant, increased generally with, but not in proportion to, the amount of toxicant applied. The area of contamination and the depth of leaching were smaller in moist soil than in drier soil, due possibly to the transport and action of dichlobenil in the vapour state. When granules were placed on sub‐irrigated soil, the maximum area of contamination was reached after 6 days for 7.5% granules, and after 12 days for 15% and 25% granules; after 19 days, the area decreased markedly, especially in the case of 7.5% granules. Soil composition, especially organic matter content, affected strongly the area of contamination near the surface and the leaching beneath.

The importance of uniform distribution of granules in field practice is stressed in conclusion.

Migration dans le sol du dichlobénil appliqué sous forme de granules
THE METABOLISM OF A SERIES OF CHLOROPHEN‐OXYALKYL ACID HERBICIDES IN BIGLEAF MAPL. E, ACER MACROPHYLLUM PURSH.*
Authors: NORRIS L. A. , FREED V. H.
Published: July 2006

Summary. Studies of the metabolism characteristics of 2,4‐D, 2,4,5‐T, dichlorprop and fenoprop were made to gain a better understanding of the differential response of a woody Plant, big leaf maPl. e, to certain phenoxy‐type herbicides. In one test in which detached leaves were used, it was established that decarboxylation is not an important detoxification mechanism in treated foliage. This same test showed the phenoxyacetic herbicides to be more stable than the α‐phenoxypropionic herbicides in treated leaves. In intact Plants 2,4,5‐T was consistently more stable than 2,4‐D, but the relative amount of metabolism of the herbicides varied with the Plant part. The results are discussed with respect to the differential response of bigleaf maPl. e.

Métabolisme d'une série d'herbicides du groupe des acides chlorophénoxyalkylés dans l'érable à grandes feuilles Acer macrophyllum Pursh.
THE ABSORPTION, TRANSLOCATION AND METABOLISM CHARACTERISTICS OF 4‐(2,4‐DICHLOROPHENOXY)BUTYRIC ACID IN BIGLEAF MAPLE*
Authors: NORRIS L. A. , FREED V. H.
Published: July 2006

Summary. Detached leaves treated with 2,4‐DB were used to demonstrate that the foliage of Acer macrophyllum Pursh. possesses the enzyme systems necessary for oxidation of the 2,4‐DB side chain. Absorption and translocation studies showed that 2,4‐DB was absorbed less but translocated more than some other phenoxy herbicides which have been tested on this species. Studies with excised stem phloem and excised roots showed that different plant tissues are not equally capable of decarboxylating 2,4‐DB. An experiment with intact plants established that 2,4‐DB was translocated unchanged, and that the primary product of the oxidation of 2,4‐DB is 2,4‐D. The results are discussed with respect to the translocation characteristics of this herbicide in bigleaf maple.

Caractères de l'absorption, de la migration et du métabolisme de l'acide 4‐(2,4‐dichlorophénoxy) butyrique dans l'érable a grandes feuilles
A RE‐EXAMINATION OF THE INFLUENCE OF LIGHT AND DARKNESS ON THE LONG‐DISTANCE TRANSPORT OF DIQUAT IN LYCOPERSICON ESCULENTUM MILL.
Authors: SMITH J. M. , SAGAR G. R.
Published: July 2006

Summary. Using autoradiographic techniques, the long‐distance transport of ‘ethylene’14C‐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‐32P and urea‐14C 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.
RESPONSE OF YELLOW NUTSEDGE, FLORIDA PUSLEY, AND PEANUTS TO THIOCARBAMATE HERBICIDES AS AFFECTED BY METHOD OF PLACEMENT IN SOIL*
Authors: HAUSER E. W. , BUTLER J. L. , SHEPHERD J. L. , PARHAM S. A.
Published: July 2006

Summary. Thiocarbamate herbicides were applied with incorporation devices and new subsurface application equipment on loamy sand at Tifton, Georgia, U.S.A. Subsurface‐applied ethyl N,N‐dipropylthiolcarbamate (EPTC), S‐propyl bulylethylthiocarbamate (pebulate), and S‐propyl dipropylthiocarbamate (vernolate) generally gave better control of Cyperus esculentus L. and Richardia scabra St Hil, but injured peanuts more than applications made on the soil surface and then incorporated into the soil. For soil incorporation, the power‐driven rotary hoe was generally better than a disc harrow.

Depth of subsurface placement critically affected herbicidal activity, especially on Cyperus esculentus; placement 1·5 in. below the soil surface gave more effective control than placement at 5·5 in.

Réactions de Cyperus esculentus, de Richardia scabra et de l'arachide mix herbicides à base de thiocarbamate, en relation avec la methode de placement dans le sol
SOME EFFECTS OF THE DESTRUCTION OF AQUATIC WEEDS IN LAKE ROTOITI, NEW ZEALAND
Authors: FISH G. R.
Published: July 2006

Summary. A bay in Lake Rotoiti was completely cleared of a heavy infestation of Lagarosiphon major by means of diquat at a concentration of 05 ppm. Weed kill was alow and there was no reduction of dissolved oxygen in the area, probably because of the cool weather at the time (April). Considerable numbers of planktonic algae developed, but after a few months it was apparent that herbicide treatment had caused an exchange of Lagarosiphon for a less massive growth of Nilelta species. Some of the changes in bio‐logical production were measured and an explanation of the observed plant succession is offered.

Quelques effets de la destruction des mausaises herbes aquatiques dans le lac Rotoiti, en Nouvelle‐Zélande
ACIDE 2,4‐DICHLOROPHÉNOXYACÉTIQUE ET CATABOLISME AUXINIQUE CHEZ HORDEUM ET TRITICUM
Authors: de FOOZ G. , GASPAR Th. , BOUILLENNE‐WALRAND M.
Published: July 2006

Résumé. Divers auteurs proposent d'expliquer les propriétés herbicides du 2,4‐D par les modifications qu'il provoque dans le métabolisme auxinique mais leurs hypothèses à ce sujet sont souvent divergentes.

L'action du 2,4‐D sur la croissance et sur le catabolisme de l'AIA a étéétudiée in vitro et in vivo chez Hordeum hexastichum et Triticum iativum cullivés à l'obscurité'. Chez ces deux espdèes, l'accroissement des concentrations dc 2,4‐D inhibe la germination ct la croissance.

Des extraits de la coléopiile et de la premiére feuille d'Hordeum montrèrent une activitéélevée de l'auxine‐oxydase, mais les extraits de Triticum furent inactils s'ils n'étaient pas additionnés de co‐facteurs tels que MnCl2 et le 2,4‐dichIorophénol: ils contiennent des inhibiteurs de la déradation enzymatique de l'auxine.

L'addition de 2,4‐D in vitro ne modifia pas la destruction de l'AIA par les extraita d'Hordeum ou de Triticum; l'inhibition du catabolisme de l'AIA, dans Hordeum, par des extraits bouillis de Triticum, ne fut pas modifie en présence de 2,4‐D. L'activité tlr l'auxine‐oxydase d'extraits d'Hordeum et de Triticum poussani en présence de 2,4‐D fut exactement identique à celle des témoins, la comparaison etant faite stir la base d'un poids frais égal. L'inhibition, dans les exlraits de Triticum, ne fut pas affecteé par le 2,4‐D.

L'action herbicidedu 2,4‐Dpursurses deux espèces, à l'obscurité, nepeut, en conséquence, èire expliqueté par une perturbation du cataboiistne de l'auxine par les auxines‐oxydases.

2,4‐dichlorophtnoxyacetic and and auxin catabolism in Hordeimi and Triticum
EFFECT OF 2,4‐D AND PICLORAM ON TRANSLOCATION OF 14C‐ASSIMILATES IN VITIS VINIEERA L.
Authors: LEONARD O. A. , WEAVER R. J. , GLENN R. K.
Published: July 2006

Summary. High concentrations of 2,4‐D and picloram interfered with the downward movement of 14c‐assimilates infield‐grown vines. The interference in translocation was appreciably greater with picloram than it was with 2,4‐D, Although basipetal translocation was retarded, translocation within the treated shoots continued from the vegetative part to the clusters. Translocation of 2,4‐D appeared to follow the same route as 14c‐assimilatcs for the most part. Formative effects were absent on untreated grape shoots although the adjacent shoots treated with 2,4‐D or picloram on the same cordons were killed; however, formative effects were evident on some of the stump sprouts which developed after the vines were harvested. The malformed leaves on the stump sprouts were twelve or more nodes from the base of the shoots, while 14c was in the more basal leaves.

Thompson Seedless (Sultanina) rootings treated with 20 000 ppm 2,4‐D or picloram transported less 14C to the roots than did the controls. Treatment with either herbicide resulted in a marked increase in the labelling of the stems.

Effet du 2,4‐D et du pichlorame sur la migration de métabolites marqués au 14C dans Vitis vinifera L.
ÉTUDES SUR LE MODE D'ACTION DU PHÉNYLCAR‐BAMOYLOXY‐2 N‐ÉTHYLPROPIONAMIDE, ISOMÉRE D
Authors: DESMORAS J. , GANTER P. , JACQUET P. , LAURENT M.
Published: July 2006

Summary. 2‐Phenylcarbamoyloxy‐N‐ethylpropionamide, D isomer (11.561 R.P.) was submitted to various physiological tests in order to characterize its properties. Although it does not affect the Hill reaction, it is able to disorganize the plant cell and inhibits tissue differentiation. It penetrates rapidly into susceptible and resistant plants, but the degradation varies with the plant family. It disappears very rapidly from susceptible species, whereas resistant plants accumulate it without any apparent damage. One of its metabolites, aniline, is present in small quantities soon after treatment but is very rapidly eliminated.

Studies showed that residues in plants were negligible at harvest.

Untersuchungen über Wirkimgsweise und Rückslände des Carbanilsäureesters des D‐Milchsäure‐äthylamids in Pflanzen