bluuebunny/crossref_metadata_2025 huggingface dataset:
EFFECTS OF WEED CONTROL AND NITROGEN APPLICATION RATE ON THE YIELD AND NTTROGEN CONTENT OF KALE
Authors: HAMMERTON J. L.
Published: July 2006

Summary. The experiments reported show that weed competition throughout growth reduced kale yields by up to 89%. Competition until the 4‐leaf stage reduced yields by about 12%. Application of nitrogen had little effect on the actual loss of yield. The same yield could be obtained by controlling weeds from emergence and giving little nitrogen, or by delaying weed control until the 4‐leaf stage and giving a higher level of nitrogen, but kale crops that had suffered weed competition until the 4‐Ieaf stage appeared to be incapable of achieving the same yield as crops clean‐weeded from emergence. Data on nitrogen percentage and content suggest that competition between weeds and kale was not solely for i

Effets du desherbage et du taux de fertilisation azoiée sur le rendement et la teneuren azote du chou fourrager
THE MOVEMENT AND METABOLISM OF PYRAZON IN TOLERANT AND SUSCEPTIBLE SPECIES*
Authors: STEPHENSON G. R. , RIES S. K.
Published: July 2006

Summary. Pyrazon (5‐amino‐4‐chIoro‐2‐phenyl‐3(2H)‐pyridazinonc) labelled with tritium in the phenyl ring, was applied to both the root and shoot of seedlings of red beet (Beta vulgaris L., cultivar Detroit Dark Red I, German millet (Setatra italica J.), and tomato (Lycopersicon esculentum Mill., cultivar Heinz 1350). Of these species, red best is tolerant, millet is moderately tolerant, and tomato is susceptible to pyrazon.

When the roots were exposed to 1–325 ppm 3H‐pyrazon in the nutrient solution, the greatest root absorption and transiocation to the shoot was observed in tomato and the least in red beet, while millet was intermediate.

Applications to the first true leaf indicated that pyrazon was absorbed by the foliage of all three but that it was not transported basipetally. The absorption and translocation studies indicated that pyrazon mi transported primarily in the xylem.

A radioactive metabolite of 3H‐pyrazon was detected in the shoots of red beet, but there was no evidence for its presence in the shoots of the other two species. Since this metabolite is radioactive, its structure must contain at least some altered form of the phenyl ring which contained the tritium in the parent molecule. This differentiates it from 5‐amino‐4‐chloro‐pyridazinone, the previously proposed degradation product of pyrazon, since this compound lacks the phenyl ring.

On the bash of these results, it is hypothesized that pyrazon will be phytotoxic if a suffic inn mm entration of the unaltered chemical reaches the site of herbicidal action in the shoot.

Migration et métabolisme de la pyrazone dans les espéces rislstantes et sensibles
STUDIES ON THE DEGRADATION OF 4‐AMINO‐3,5,6‐TRICHLOROPlCOLINIC ACID IN SOIL
Authors: GROVER R.
Published: July 2006

Summary. Picloram was incubated at concentrations of 0, 0·25, 0·5 and 1 ppmw in Regina heavy clay topsoil maintained at moisture‐holding capacity and a t 25° C The herbicide was quantitatively bioassayed at regular intervals. There was a lag period prior to degradation at all concentrations. The duration of the lag period increased as the concentration of picloram in the soil was increased. Al the end of each lag period, the degradation of picloram occurred as a first‐order reaction, i.e. the rate of degradation was independent of the concentration of picloram in the soil. Due to the pronounced variations in the duration of the lag periods with concentration, the assignment of half‐value or half‐life periods to picloram degradation in soil is considered to be of doubtful significance.

Etude de la degradation de t'acide 4‐amino‐3,5,6‐trichloropicolmique dans le sol
ÉTUDE DE L'INFLUENCE DE LA NATURE DU SOL SUR L'ACTION HERBICIDE DE LA SIMAZINE*
Authors: BOUCHET F.
Published: July 2006

Summary. Several biological tests were made to determine the effect of soil type on the activity of simazine. Studies with four soils‐a sandy loam, a loamy sand, a calcareous soil and an organic sand‐showed that after leaching with 200 mm water the greatest concentration of simazine remained in the superficial layer. In another experiment with aqueous suspensions of simazine and colloids it was found that simazine was strongly held by montmorillonite and especially by humic acids, but that herbicidal activity was not lost. A fourth experiment confirmed that free organic matter obtained from an organic sand is able to inactivate simazine.
THE COMBINED ACTION OF 3‐AMINO‐1,2,4‐TRIAZOLE AND AMMONIUM THIOCYANATE ON PHOSPHATASE ACTIVITY IN COTTON THISTLE (ONOPORDUM ACANTHIUM L.)
Authors: MICHAEL P. W.
Published: July 2006

Summary. In phosphatase extracts prepared from untreated leaves of Onopordum acanthium, phosphatase activity was stimulated by amitrole (0·04 M) and ammonium thioeyanate (0·04 M), alone and together. The effect of the mixture of amitrole and ammonium thioeyanate was more than additive in experiments set up at pH 4·0, less than additive at pH 4·6 and roughly additive at pH 5·3 and 5·8. The effect of amitrole alone could be explained simply in terms of the increase in pH it effected.

In leaves harvested 4, 7 and 9 days after spraying rosettes with 1/8 lb/ac (140 g/ha) amitrole and 1/4 lb/ac (280 g/ha) ammonium thioeyanate, alone and together, more than additive or additive increases in phosphatase activity of plants sprayed with the mixture were recorded. These increases are interpreted as being due to increases in the amount of soluble protein.

Inorganic phosphate levels showed different trends with time in plants treated with amitrole alone compared with plants treated with the mixture of amitrole and ammonium thioeyanate.

These interactions between amitrole and ammonium thioeyanate are taken to indicate a possible chemical basis for the increased herbicidal activity of the mixture over amitrole alone.

Histochemical studies on the mature leaves of rosettes showed that phosphatase activity was confined to the vascular tissues while in the very young leaves it was high in the chlorenchymatous tissue and appreciable in the epidermal and hair cells.

Attention is drawn to the strong buffering action of amitrole in the pH range 4·0–5·3. This may be relevant to herbicidal activity, the vacuolar pH of the outer cells of leaves of Onopordum being in the range 4·8‐5·2.

L'action combinée du 3‐amino‐1,2,4‐triazole et du thioeyanate d'ammonium sur l'activité de la phosphatase chez Onopordum acanthium L.
RELATION BETWEEN STRUCTURE AND HERBICIDAL ACTIVITY OF SUBSTITUTED BENZOTHIADIAZOLES (2,1,3)
Authors: KOOPMAN H. , van DAALEN J. J. , DAAMS J.
Published: July 2006

Summary. A large number of substituted benzothiadiazoles (2,1,3) was synthesized. In this report, the herbicidal activities of some halo‐ and alkyl‐substituted benzothiadiazoles (2,1,3) are described. It was found experimentally that at least one of the positions 5 and 6 in the molecule must be unsubstituted. Some di‐ and tri‐substituted derivatives had excellent herbicidal activities, in contrast to tetra‐substituted benzothiadiazoles (2,1,3).

Relation entre la structure et I'activité herbicide des (2,1,3) benzothiadiazoles substitués
FACTORS AFFECTING THE ACTIVITY OF DI‐ALLATE AND TRI‐ALLATE
Authors: BANTING J. D.
Published: July 2006

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
SITE OF UPTAKE OF SOIL‐APPLIED HERBICIDES*
Authors: PRENDEVILLE G. N. , ESHEL Y. , SCHREIBER M. M. , WARREN G. F.
Published: July 2006

Summary. We conducted studies to determine the effects on corn (Zea mays L, var. Indiana 654) and pea (Pisum sativum L. var. Alaska) of localizing various herbicides in the soil, using a double plastic pot technique which ensured separate exposure of the root and shoot zones of the plants to treated soil. Effects on corn and pea were similar in relation to site of uptake. 2,4‐D‐amine, naptalam, simazine, diuron and dalapon‐sodium entered primarily through the roots. Some shoot entry and also severe inhibition of roots occurred in soil treated with 2,4‐D and naptalam; these were noticed only to a slight extent with the other three herbicides.

EPTC, chlorpropham and trifluraiin were most effective when applied to the shoot zone. Little effect on foliage growth was evident when the root zone alone was treated. However, roots in treated soil were severely inhibited by these three herbicides. Dinoseb displayed a contact type of action, injuring both shoots and roots. Treatment of both zones had an additive effect.

Entry of chlorthal‐methyl which was tested on a susceptible species, sorghum (Sorghum vulgare Pers.) was mainly through the shoot, with only a slight effect on top growth when roots alone were treated. Roots in treated soil were slightly inhibited.

Localisation de l'absorption des herbicides appliqués sur le sol
COMPETITION OF WILD OATS (AVENA FATUA L.) IN WHEAT AND FLAX*
Authors: BOWDEN B. A. , FRIESEN G.
Published: July 2006

Summary. This project was designed to study various aspects of wild oat competition in spring wheat and flax. From ten to forty wild oat plants/yd2 were sufficient to cause significant yield reductions in wheat when grown on summerfallow land or when ammonium phosphate fertilizer was added to stubble land. However, when wheat was grown on stubble land without the benefit of a fertilizer treatment, seventy to one hundred wild oat plants/yd2 were needed to suppress wheat yields significantly. This would suggest that on stubble land, soil fertility was a more important factor than moderate densities of wild oats in determining eventual crop yields. In these experiments, wild oats reduced the number of tillers per plant, but did not significantly affect the protein content of the harvested grain.

Only ten wild oat plants/yd2 were sufficient to reduce flax yields significantly on both summerfallow and stubble land. The only exception was in 1966, when flax grown on summerfallow land was not significantly affected until the density of wild oats reached forty plants/yd2. This confirms the general observation that flax is a poor competitor with wild oats.

The results suggest that wild oat competition had already commenced prior to emergence of wheat, particularly with the higher densities of wild oats. In general, competitive effects increased with time and with wild oat density. In flax, severe competition had already taken place prior to the 2–3‐Ieaf stage of the weed in 1964, but did not become severe until after the 2–3‐leaf stage of wild oat growth in 1965 and 1966. Again, competitive effects increased with time and with wild oat density.

Results of a final series of experiments, suggested that the optimum seeding date for flax in Manitoba is the latter part of May or the first week of June. Yield reductions due to wild oat competition became very severe as seeding dates were delayed.

La compétition de la folle avoine (A vena fatua L.) avec le blé et le lin
PHYTOTOXICITY OF PARAQUAT ON WHITE AND GREEN HIBISCUS, SORGHUM AND ALPINIA LEAVES*
Authors: BOVEY R. W. , MILLER F. R.
Published: July 2006

Summary. Paraquat was applied to while, variegated and green leaves of Hibiscus rosa sinensis L. Visual observations and moisture loss determinations revealed that the rate of tissue kill by paraquat was reduced in while tissue. Evidence from paraquat absorption and concentration studies indicated that phytotoxic differences were not due to amount or rate of absorption or protoplasmic susceptibility, but to differences in chlorophyll Content of treated leaves. Desiccants such as dinoseb, not dependent upon chlorophyll for rapid action, were equally affective on white and green leaves. The same reduced activity of paraquat on white leaf tissue was demonstrated for other species.

Phytotoxicité du paraquat appliqué sur les feuilles blanches ou vertes de l'hibiscus, du sorgho et de l'alpinia
THE PHYTOTOXICITY OF SOME HERBICIDES IN FIELD AND POT EXPERIMENTS IN RELATION TO SOIL PROPERTIES
Authors: HANCE R. J. , HOCOMBE S. D. , HOLROYD J.
Published: July 2006

Summary. The phytotoxicities in a number of soils of lenacil, linuron, prometryne and simazine to two indicator plants were determined in field and glasshouse experiments. The results were compared with estimates of the adsorption capacity of the soils obtained by two methods using dimethylaminobenzaldehyde as a model adsorbate. The possible influence of other soil properties was also considered.

One of the adsorption measurements had some predictive value for glasshouse behaviour but was not markedly superior to soil organic carbon content for this purpose. None of the factors studied was usefully correlated with field performance. Results from field experiments in spring were poorly correlated with those from similar experiments in autumn. Neither set of field results related closely to those obtained in the glasshouse. It is concluded that the influence of climate was more important than that of soil type.

La phytotoxiciti de quelquts herbicides dans des experiences en pots et en plein champ, en relation avec les propriétés du sol
CHEMICAL CONTROL OF FERTILE SPARTINA TOWNSENDII (S.L.) ON THE CHESHIRE SHORE OF THE DEE ESTUARY I. FIELD TRIALS ON SPARTINA SWARD
Authors: TAYLOR MONICA C. , BURROWS ELSIE M.
Published: July 2006

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
THE INFLUENCE OF SIZE OF SPRAY DROPLETS ON THE HERBICIDAL ACTIVITY OF DIQUAT AND PARAQUAT
Authors: DOUGLAS G.
Published: July 2006

Summary. Single droplets ranging in size from 250 to 1000 μ diameter and concentrations of diquat and paraquat over the range 0–09–0.75% ion were examined for herbicidal activity. Size of droplet and concentration of herbicide in the droplet were shown to have a marked influence on activity. An increase in droplet size above 250 μ increased herbicidal efficiency. An optimum was reached between 400 and 500 μ while activity fell off with a further increase to 1000 μ.
CHLORAMBEN (AMIBEN) DEGRADATION JN SOIL
Authors: WILDUNG R. E. , CHESTERS G. , ARMSTRONG D. E.
Published: July 2006

Summary. When columns of three soil types were perfused with a microbial medium containing 5·7 and 26·9 ppm 14COOH‐labelled chloramben, there was a rapid decrease in the 14C activity remaining in solution, attributable to soil adsorption. Soil pH and organic matter content were the primary factors controlling chloramben adsorption. Soil pH may enhance adsorption through its effect on the number of soil anion exchange sites, and sites for polyvalent cation bridging and H bonding. Following adsorption, liver decreases in solution 14C‐chloramben activity were attributed to degradation;14CO2 evolved during perfusion amounted to 25–30% of the total decrease in 14C‐chloramben from solution. It was concluded that more than 90% of the 14C‐activity remaining in solution could be attributed to intact chloramben. Thus, decarboxylation appeared to be the primary mechanism of chloramben degradation in soils. Lag phases observed during degradation and subsequent investigations with re‐amended solutions implicated the soil microflora; even at chloramben concentrations of 26.9 ppm no toxic effect on the chloramben‐degrading micro‐organisms was apparent.

Dégradation du chlorambène [amibène) dans le sol
THE BASIS OF THE DIFFERENTIAL PHYTOTOXICITY OF 4‐HYDROXY‐3,5‐DI‐IODOBENZONITRlLE*
Authors: DAVIES P. J. , DRENNAN D. S. H. , FRYER J. D. , HOLLY K.
Published: July 2006

Summary. Entry of ioxynil‐14C into portions of leaves was greater with mustard than with barley or pea and was unrelated to stomatal density. Measurement of ioxynil content of sprayed plants showed that by increasing the concentration of ioxynil and adding a surfactant, almost as much ioxynil could be made to enter barley as entered mustard from a lower concentration without surfactant. Auto radiographs showed that a limited amount of 14C was translocated to a small extent in plants following localized application of ioxynil‐14C. An experiment comparing leaf removal by cutting with destruction of equivalent leaf areas by ioxynil treatment suggested a greater translocated effect of ioxynil with mustard than with pea or barley.

Les principes de la phytotoxicité différentielle du 4‐hydroxy‐3,5‐di‐iodobetZonitrile II. Absorption et migration
STUDIES ON HERBICIDE CONTENTS IN ROOTS OF SKELETON WEED (CHONDRILLA JUNCEA L.) FOLLOWING LEAF APPLICATIONS
Authors: GREENHAM C. G.
Published: July 2006

Summary. The herbicides studied were 2,4‐D, 2,4‐DB, dicamba and orthoarsenic acid. Herbicide content in the roots was taken as an overall measure of penetration into and absorption by the leaves, and of translocation to the roots.

A significantly greater 2,4‐D content resulted from foliar application at pH 3–5 than at higher values, though at pH 8–5 the inclusion of triethanolamine significantly increased the 2,4‐D content. No evidence was obtained that a greater 2,4‐D content should result from foliage applications of 2,4‐DB than from 2,4‐D. Dicamba gave a greater herbicide content than 2,4‐D when applied at high concentration at 20° C but not at 25° C, probably because of less injury at the lower temperature.

Concentrations of Tween 20 up to 2% had no deleterious effect on the 2,4‐D content; on the other hand 2,4‐D content was lowered by 0–25% or more of cetyltrimethyl‐ammonium bromide. Poor wetting is not the cause of the variable herbicide contents sometimes obtained.

Orthoarsenic acid, which has given better control of the weed than 2,4‐D, was very poorly translocated; its effectiveness is due to its high intrinsic toxicity.

Etudes sur la teneur en herbicide des racines de Chondrilla juncea L. á la suite d'applications sur les feuilles
THE EFFECT OF JULY APPLICATIONS OF DALAPON ON THE GROWTH AND BOTANICAL COMPOSITION OF AN AGROSTIS/LOLIUM PASTURE
Authors: ALLEN G. P.
Published: July 2006

Summary. Dalapon–sodium at 3.3–7.5 Ib ac/a.e. was applied in early, mid– and late July 1964 to an Agrostis/Lolium pasture for selective control of the weed grasses Agrostis stolonifera, Poa trivialis and Holcus lanatus. These species were significantly more susceptible than Lolium perenne to dalapon at all doses regardless of the time of spraying. The most promising treatment was 33 lb/ac applied on 4th July, which increased the ground cover of L. perenne and substantially reduced Agrostis stolonifera and Poa trivialis. The total yield of herbage 12 weeks after spraying was only 50% of that from the unsprayed control, but the yield of Lolium perenne was not affected. When cut on 21st May and 5th August 1965, total yield was only slightly reduced and that of L. perenne was increased by 60–90%. The successful practical utilization of this selectivity is likely to depend largely on the spacing of the plants of L. perenne in the pasture. Simazine at 0.75 Ib/ac applied to half of each plot 3–4 weeks alter dalapon treatment had no lasting beneficial effect on the composition of the sward.
THE YIELD AND QUAEITY OF RED BEET SEED AS AFFECTED BY DESICCANT SPRAYS AND HARVEST DATE
Authors: AUSTIN R. B. , LONGDEN P. C.
Published: July 2006

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
EFFECTS OF DESICCATION AND TEMPERATURE ON SURVIVAL OF CYPERUS ESCULENTUS TUBERS AND CYNODON DACTYLON RHIZOMES
Authors: THOMAS P. E. L.
Published: July 2006

Summary. The effects of all combinations of five desiccation treatments, two temperatures and three durations of desiccation on the survival of Cyperus esculentus tubers and two‐node Cynodon dactylon rhizome fragments were examined in laboratory and glasshouse experiments.

Cyperus esculentus tuber survival was greater at 22°C than at 4°C. Duration of desiccation did not influence tuber survival, except at the lower temperature.

Survival of Cynodon dactylon rhizome fragments was greatly influenced by desiccation treatment, duration of desiccation and the interaction of these two factors. No buds survived when rhizomes reached 50% of their original weight, indicating good tolerance of desiccation since the original dry‐matter content of rhizomes in this experiment was 41·2%.
CHLORTHAL DEGRADATION IN SOILS AND ITS UPTAKE BY PINE SEEDLINGS
Authors: IYER J. G. , CHESTERS G. , WILDE S. A.
Published: July 2006

Summary. Similar chlorthal (dimethyl 2,3,.5,6‐tetrachloroterephthalate) degradation patterns were found in pot cultures of white pine and Monterey pine grown in a sandy soil and in fallow cultures of the same soil. After 120 days, the content of chlorthal plus its degradation products (as measured by 14C‐activity) had decreased to 37% in the fallow and white pine cultures. A somewhat slower rate of degradation in soil (average 45%*C‐activity remaining) was observed for the Monterey pine cultures. Thus in 120 days, 55–63% of the added chlorthal had been lost from the soil system. A negligible amount of this could be accounted for by plant uptake. After 60 days of growth the rate of degradation in soil was greatly curtailed suggesting that the accumulated degradation produces were able to inhibit the further degradation of the herbicide.

Analysis of *C‐labelled extracts from the pine tissue showed that uptake of chlorthal varied from 0–25 to 1–2% of the total amount of the chemical added to the soil. Degraded, as well as intact chlorthal, were found in both Monterey and white pine tissue. Very limited mobility of chlorthal in the plant was observed and the concentration in the shoots was less than 10 pm. About 80% of the absorbed chlorthal remained in the root systems. Plant growth led to a rapid dilution of absorbed chlorthal. The growth of both species of pine was rapid and apparently healthy in chlorthal‐treated soil and comparable to that of the control plants.
EFFECT OF PYRAZON ON PHOTOSYNTHESIS OF VARIOUS PLANT SPECIES
Authors: ESHEL Y.
Published: July 2006

Summary. Studies were conducted to determine the influence of pyrazon (5‐amino‐4‐chloio‐2‐phenyl‐3(2H)‐pyridazinone) on photosynthesis. A strong inhibiting effect on O2 evolution from leaf discs of several species was recorded. For most species a concentration of 5 × 10−5 M caused a reduction of about 50% in the rate of photosynthesis. Photosynthesis of sugar beet, highly resbtant to pyrazon, was reduced to 50% by a concentration of 7–5 × 10−5 M. Since these differences cannot account for the great divergence in susceptibility to pyrazon, it is suggested that the selectivity of this herbicide results from degradation and differential accumulation in the foliage.

Pyrazon was phytotoxic to plants of tomato and pigweed (Amaranthus retrofiexus L.) kept in the light but not when kept in the dark, after foliage application. The conclusion that pyrazon inhibits the mechanism of photosynthesis and causes starvation for carbohydrates, was strengthened by the fact that external feeding of glucose overcame the toxicity of the compound in tomato plants. These results and a possible mode of selectivity are discussed.
EFFECTS OF ANNUAL WEEDS AND CULTIVATION ON THE YIELD OF PEANUTS*
Authors: HAUSER E. W. , PARHAM S. A.
Published: July 2006

Summary. Undisturbed natural infestations of annual weeds, mainly Digitaria sanguinalis (L.) Scop, and Richardia scabra L., reduced the yield of harvestable peanuts [groundnuts) by an average of 20% over an 8‐year period. Yield reductions in individual years ranged from I to 50%, depending mainly on the density of the weed population. From one to 5%‘non‐dirting’ cultivations generally did not reduce yield as compared with hand weeding, unless environmental conditions favoured development of the disease southern blight (Sclerotium rolfsii Sacc.) on uncultivated peanuts.
SOME EFFECTS OF DROPLET SIZE AND POSITION ON THE RESPONSE OF LETTUCE TO SUB‐LETHAL DOSES OF MCPA
Authors: WAY J. M.
Published: July 2006

Summary. Senescent, expanded or expanding leaves of lettuce plants were treated individually with MCPA. The subsequent development of auxin‐induced symptoms throughout the plants was recorded. The number of leaves affected and the severity of the symptoms increased with application to the less mature leaves. In addition more leaves were affected when the application was made to larger plants than to smaller ones. These results were associated with absorption/translocation differences in the leaves of different ages, and in their spatial relationship to tissues at particularly susceptible stages of development. In further experiments, applications of similar weights of MCPA to lettuce plants in droplet sizes of approximately 100 μ and 500 μ were compared. There were consistent trends for the small droplets to produce greater effects.

Quetques effets de la taille des gouttelettes et de leur position sur la reaction de la laitue à des doses sub‐létales de MCPA
FACTORS AFFECTING THE LOSS OF TRI‐ALLATE FROM SOILS
Authors: SMITH ALLAN E.
Published: July 2006

Summary. Electron‐capture gas chromatography was used to detect tri‐allate residues in persistence studies with two soils. At rates equivalent to 0–75, 15 and 3 Ib/ac, 50% of the amount applied was degraded in 8–11 weeks at 25°C in moist Regina heavy clay and Weyburn loam. No loss occurred in sterile soils, indicating that microbial degradation may be a, major factor contributing to tri‐allate breakdown.

When aqueous solutions buffered at pH 4–8 were held at 25° G, only 10–15% of the tri‐allate was chemically degraded during 24 weeks.

At the normal field rate of 1·25 Ib/ac, tri‐allate was not readily leached. From soil columns of Weyburn loam, 5–7% was eluted by 9 in. of water; with clay the corresponding value was 12–13% of the amount applied. When field plots were sprayed with 125 lb/ac in April, tri‐allate could still be detected until the soil froze in November.

Facteurs agissant sur la perte de tri‐allate dans les sots
THE DECOMPOSITION OF UREA HERBICIDES BY BACILLUS SPHAERICUS, ISOLATED FROM SOIL
Authors: WALLNÖFER P.
Published: July 2006

Summary. The decomposition of seven urea herbicides by Bacillus sphaericus was studied. Experiments with 14C‐labelled monolinuron demonstrated that monolinuron was degraded by removal of CO2 from the ureido portion of the molecule and leaving the /Kchloroaniline moiety. Tests with monuron, diuron, monolinuron, linuron, metobromuron, fluometuron and methabenzthiazuron indicated that B. sphaericus was only able to decompose the methoxy compounds monolinuron, linuron and metobromuron in this way. All compounds were identified by infrared spectroscopy. A pathway for degradation of the herbicides by B. sphaericus is proposed.
ACTION D'UNE URÉE SUBSTITUÉE, LE MÉTHBENZ‐THIAZURON, SUR LA CROISSANCE DE PLANTULES DE BLÉ ET RÔLE DES ADDITIFS
Authors: COLLET G. F.
Published: July 2006

Résumé. Une nouvelle urée substitutée le méthbenzthiazuron (N‐benzothiazol‐2‐yl‐NN′‐diméthylurée), a été utilisée en culture hydroponique de Triticum sativum cv. Vilmorin 27. La substance active selon qu'elle est pure ou sous sa forme commerciale provoque des inhibitions de croissance différentes. On a mis en évidence le röle joué par les ingrédients théoriquement inactifs ajoutés à la substance active. L'utilisation de diquat marqué permet de conclure à la présence de l urée dans i'ensemble des tissus. La cinétique de la réponse suggére un phénoméne de détoxification. C'est la concentration extérieurc aux racines qui provoque T inhibition de croissance.
METABOLISM OF DICHLOBENIL IN SANDY SOIL
Authors: VERLOOP A. , NIMMO W. B.
Published: July 2006

Summary. A study was made of the breakdown of 14C‐dichlobenil (2,6‐dichlorobenzonitrile) added at 2 ppm to a sandy soil containing 4% organic matter. After 8 months more than half the added herbicide had been metabolized. The major conversion product was 2,6‐dichlorobenzamide (95% of total metabolites). Three minor metabolites (each about 1%) were found but could not be identified. The hydrolysis to 2,6‐dichlorobenzamide appears to be a microbiological process. The great stability of the major metabolite was confirmed in a separate experiment in which 14C‐2,6‐dichlorobenzamide was added to the soil at 2 ppm. After 6 months about 90% of the added 2,6‐dichlorobenzamide was recovered.

Métabolisme du dichlobenil en sol sableux

Résumé. La degradation du 14C‐dichlobenil (2,6‐dichlorobenzonitrile), a étéétudiée, à la concentration de 2 ppm, dans un sol sableux contenant 4% de matiére organique. Après huit mois, plus de la moitié de I'herbicide apporté avait été métabolisé. Le plus important des produits de dégradation fut le 2,6‐dichlorobenzamide (95% du total des metabolites). Trois métabolites mineurs, représentant environ 1% chacun furent trouvés mais ne purent étre identifiés. L'hydrolyse à la 2,6‐dichlorobenzamide semble être un processus microbiologique. La grande stabilityé du métabolite principal fut confirmée dans une autre expérience dans laquelle le 14C‐2,6‐dichlorobenzamide fut ajouté au sol à raison de 2 ppm. Après 6 mois, 90% environ du 2,6‐dichlorobenzamide fut retrouve.

Abbau von Dichlobenil in Sandboden

Zusammenfassung. Es erfolgte eine Untersuchung über den Abbau von 14C‐Dichlobenil (2,6‐Dichlorbenzonitril), dass in einer Konzentration von 2 ppm einem Sandboden mit 4% organischer Substanz zugegeben worden war. Nach 8 Monaten war mehr als die Halfte des zugefügten Herbizids abgebaut. Das wichtigste Abbauprodukt war 2,6‐Dichlorbenzamid (95% der gesamten Abbauprodukte). Drei weniger bedeutende Abbauprodukte (jedes weniger als 1%) wurden gefunden, doch konnten sie nicht identifiziert werden. Die Hydrolyse in 2,6‐Dichlorbenzamid ist offensichtlich ein mikrobiologisch bedingter Vorgang. Die grosse Stabilitat des wichtigsten Metaboliten wurde in einem getrennten Versuch bestatigt, in welchem 14C‐2,6‐Dichlorbenzamid dem Boden in einer Konzentration von 2 ppm zugefuhrt wurde. Nach 6 Monaten wurden ungefahr 90% des zugefügten 2,6‐Dichlorbenzamid wiedergefunden.
DIFFUSION COEFFICIENTS FOR TWO TRIAZINE HERBICIDES IN SIX SOILS
Authors: WALKER A. , CRAWFORD D. V.
Published: July 2006

Summary. Diffusion of the triazine herbicides propazine and prometryne was studied in six soils. Apparent diffusion coefficients were calculated from the distribution of herbicide in a column of soil after diffusion from one half of the column for a known time. The magnitude of the diffusion coefficients varied from 1·5 × 10−9 cm2 sec−1 for propazine in a sandy soil to 3·1 × 10−9 cm2 sec−1 for prometryne in an organic soil. Under the conditions of measurement, the diffusion coefficients decreased in proportion to the extent of adsorption. Calculations were made to determine over what distances diffusion could be of importance in the movement of these herbicides.

Coefficients de diffusion de deux triazines herbicides dans six sols

Résumé. La diffusion de deux triazines herbicides, la propazine et la prometryne a étéétudiée dans six sols. Les coefficients de diffusion apparente furent calculés selon la distribution de I'herbicide dans une colonne de sol, aprés diffusion à partir de la moitié de la colonne pendant un temps connu. Les coefficients de diffusion variérent de 1,5 × 10−7cm2 see−1 pour la propazine dans un sol sableux, á 3,1 × 10−9 cm2 sec−2 pour la prométryne dans un sol organique. Dans les conditions oú les mesures furent effectuées, les coefficients de diffusion diminuérent en proportion de 1′étendue de l'adsorption. Des calculs ont été effectués pour detérminer au‐delá de quelles distances la diffusion pouvait presenter une importance dans le mouvement de ces herbicides.

Difftisions‐KoeffizienUnfur zwei Trtazin‐Deriaate in sechs Böden

Zusammenfassung. Die Diffusion der beiden Triazin‐Derivate Propazin und Prometryn wurde in sechs Böden untersucht. Die Diffusions‐Koeffizienten wurden aus der Verteilung des Herbizids in einer Bodensaule nach Diffusion aus der einen Säulenhalfte in einer bestimmten Zeit errechnet. Die Grösse der Diffusions‐Koeffizienten variierte von 1,5 × 10−7 cm2× sec−1 bei Propazin in einem Sandboden bis 3,1 × 10−9 cm2× sec−1 bei Prometryn in einem Humus‐Boden. Unter den gegebenen Versuchsbedingungen nahmen die Diffusions‐Koeffizienten in Abhángigkeit von der Stärke der Adsorption ab, Es wurden Berechnungen darüber angestellt, über welche Entfernungcn die Diffusion dieser Herbizide im Boden eine Rolle spielen könnte.
THE INHIBITION OF GIBBERELLIC ACID INDUCTION OF α‐AMYLASE ACTIVITY IN BARLEY ENDOSPERM BY CERTAIN HERBICIDES
Authors: DEVLIN ROBERT M. , CUNNINGHAM RICHARD P.
Published: July 2006

Summary. The influence of the four herbicides 2,6‐dichlorobenzonitrile (dichlobenil), isopropyl‐N‐(3‐chlorophenyl)carbamate (chlorpropham), 2‐chloro‐N‐isopropylacetani‐lide (propachlor) and 2‐chloro‐2′,6′‐diethyl‐N‐(methoxymethyl)acetanilide (alachlor) on GA induction of a‐amylase in the barley endosperm test was studied. Amylase induction by GA was inhibited by all four herbicides, dichlobenil and chlorpropham being more active in this respect. In all cases, inhibition increased with the addition of increasing concentrations of herbicide. Addition of the herbicides to the reaction mixture showed that none of them directly affected the enzyme—starch reaction.

Inhibition de V induction par l'acide gibbirellique de activité de α‐amylase dans l’endosperne de I'orge, sous faction de certains herbicides

Résumé. Les auteurs ont étudié l'influence de 4 herbicides, le 2,6‐dichlorobenzonitrile (dichlobénil), le. N‐(3‐chlorophényle) carbamate d'isopropyle (chlorpropham), la 2‐chloro‐N‐iso‐propylacétanilide (propachlore) et la 2‐chloro‐2′,6′‐diéthyl‐N‐(méthoxy‐méthyle) acétanilide (alachlore), sur l'induction par l'acide gibbérellique de l'α‐amylase dans l'endosperme de I'orge. L'induction de l'amylase par l'acide gibbérellique fut inhibée par les quatre herbicides, le dichlobénil et le chlorpropham se montrant les plus actifs à cet égard. Dans tous les cas, l'inhibition s'accrut avec I'addition de concentrations croissantes d'herbicide. L'addition des herbicides au mélange en réaction montra qu'aucun d'entre eux n'affectait directement la réaction enzymatique de l'amidon.

Die Hemmung der gibberellininduzierten α‐Amylaseaktimtdt in Gerstenendosperm durch gewisse Herbizide

Zusammenfassung. Der Einfluss der vier Herbizide 2,6‐Dichlorbenzonitril (Dichlobenil), Isopropyl‐N‐(3‐chlorphenyl)‐carbamat (Chlorpropham), 2‐Chlor‐N‐isopropylace‐tanilid (Propachlor) und2‐Chlor‐2′,6′‐diäthyl‐N‐(methoxymethyl)‐acetanilid (Alachlor) auf die gibberellininduzierte α‐Amylasebildung in Gerstenendosperm wurde untersucht. Die Induktion von α‐Amylase durch Gibberellinsäure wurde von alien vier Herbiziden ge‐hemmt. Am wirksamsten waren hierbei Dichlobenil und Ghlorpropham. In alien Fällen wurde die Hemmwirkung durch ansteigende Herbizidkonzentrationen verstärkt. Die Zugabe der Herbizide zu dem Reaktionsgemisch zeigte, dass keines von ihnen die Reaktion zwischen Enzym und Stärke direkt beeinflusste.
METHODEN ZUR RÜCKSTANDSBESTIMMUNG VON PHENMEDIPHAM IN PFLANZENMATERIAL
Authors: KOSSMANN K.
Published: July 2006

Zusammenfassung. Es werden Methoden zur photometrischen bzw, gaschromatografischen Rückstandsbestimmung von Phenmedipham in Betarüben und deren Blättern, in Zucker und seinen Nebenprodukten, in Erdbceren und anderen Kulturpflanzen beschrieben. Mit der Photometrie wird eine Nachweisgrenze von 0,1 ppm erreicht. Die Gaschromatografic erlaubt noch die Bestimmung von 0,02 ppm Phenmedipham.

Methods for residue analysis of phenmedipham in plant material

Summary. Photometric and gas chromatographic methods are described for the residue analysis of phenmedipham in roots and leaves of sugar beet, in sugar and its by‐products, in strawberries and in other crops. The photometric method allows a minimum residue of 0.l ppm to be determined; with the gas chromatographic method, as little as 0–02 ppm phenmedipham can be determined.

Méthodes pour l'analyse des résidus de phenmédiphame dans Le matériel végétal

Résumé. Des méthodes de photométrie et de chromatographie en phase gazeuse sont décrites pour l'analyse des résidus de phenmédiphame dans les racines et les feuilles de la betterave á sucre, dans le sucre et ses dérivés, dans les fraises et dans d'autres plantes cultivées. La méthode photométrique permet de déceler un résidu minimum de 0,1 ppm; avee la méthode de chromatographie en phase gazeuse, il peut étrc décelé une quantité aussi faible que 0,02 ppm de phenmédiphame.
RESIDUAL ACTIVITY OF PARAQUAT IN SOILS I. FACTORS AFFECTING PERSISTENCE
Authors: WATKIN E. M. , SAGAR G. R.
Published: July 2006

Summary. Phytotoxic residues were recorded on soil surfaces sprayed with paraquat (1,1′‐dimethyl‐4,4′‐bipyridylium‐2A) at 1 and 2 Ib/ac a.i. Phytotoxicity was greater on organic than on mineral soils though on both the residues persisted unchanged for at least 14 days and were greater with the higher dose.

Germination of Brassica napus L. was only slightly affected and most seedlings did not show phytotoxic symptoms until after cotyledon expansion. The cotyledons of Trifolium repens L. showed symptoms on emergence from the testa. By contrast, grains of Lolium perenne L. either failed to germinate on paraquat‐treated soils or showed reduced germination.

Seedlings of T. repens were susceptible; both root and shoot systems were affected as they grew through layers of soil previously treated with paraquat. Ground limestone appeared to reduce the phytotoxicity of paraquat under some circumstances. Phytotoxic residues were not reduced by surface irrigation but disappeared if the soil surface was disturbed mechanically.
SEED PRODUCTION OF AGROPYRON REPENS (L.) BEAUV. IN ARABLE CROPS IN ENGLAND AND WALES IN 1969
Authors: Williams E. D. , Attwood P. J.
Published: July 2006

Summary. Spikes oi Agropyron repens (L.) Beauv. were collected from field crops (mostly spring barley and winter wheat) in England and Wales near the time of crop harvest. Seeds per spike were counted and their germination tested in soil in the glasshouse.

About 95% of the samples contained viable seeds; about one third of the samples had fewer than 5 viable seeds/spike, a third between 6 and 15 and a third more than 15. The average number of viable seeds/spike for all samples was 13. Spikes from spring barley (152 samples) had an average of 11 and a maximum of 51 viable seeds and those from winter wheat (42 samples), 20 and 48 respectively. Samples collected within 3 weeks after mid‐July had fewer viable seeds/spike than those collected later. Samples containing morphologically‐different spikes had more viable seeds/spike than apparently uniform samples, and spikes from dense field populations more seeds than those from sparse populations.
OCCURRENCE AND PERSISTENCE OF PICLORAM IN GRASSLAND WATER SOURCES
Authors: HAAS R. H. , SCIFRES C. J. , MERKLE M. G. , And R. R. HAHN , HOFFMAN G. O.
Published: July 2006

Summary. At 2 weeks following application, concentrations of picloram in surface runoff water collected adjacent to a South Texas grassland treated with 1·1 kg/ha ranged from 0·055 to 0·184 ppm as detected by gas chromatography. Picloram in surface runoff water diminished with time and amount of rainfall as a decay function. Picloram was not detectable in a flowing stream 0·8 km below a 32‐ha area treated with 1·1 kg/ha. Residual picloram was not detected in domestic water wells at any time up to 2 years following treatment of adjacent areas with 1·1 kg/ha.

Dissipation of picloram from treated livestock‐watering ponds was concentration‐dependent, with the final losses resulting largely from dilution. Initial loss rates in the ponds ranged from 14 to 18%/day but decreased to less than 1%/day at 100 days following treatment. After 100 days, when the concentrations were less than 0·005 ppm, the primary changes in picloram content appeared to be due to dilution from rainfall or to concentration by runoff from adjacent treated areas.
MOVEMENT AND FATE OF FLUORODIFEN‐1′‐14C IN CUCUMBER SEEDLINGS
Authors: EASTIN E. F.
Published: July 2006

Summary. Autoradiographs and liquid scintillation counts of cucumber (Cucumis sativus L. cv. Ashley) seedlings indicated rapid absorption and translocation of radioactivity from fluorodifen‐1′‐14C (p‐nitrophenyl‐α,α,α‐trifluoro‐2‐nitro‐p‐tolyl ether labelled with 14C in the 1 position of the p‐nitrophenyl ring). After 24 h in 1 mg/1 of fluoro‐difen‐1′‐14C, 25% of the absorbed radioactivity was translocated from the roots.

Cucumber seedlings degraded fluorodifen‐1′‐14C via a pathway similar to that reported for peanut seedlings but at a slower rate. The major degradation products were p‐nitrophenol and an unidentified polar compound (Unknown I). More rapid absorption and translocation coupled with slower degradation by cucumber as compared with peanut seedlings are factors which may contribute to the susceptibility of cucumber to fluorodifen.
A RAPID BIOASSAY FOR DIPHENAMID AND ITS APPLICATION IN SOIL STUDIES*
Authors: And M. HOROWITZ , HULIN NIRA
Published: July 2006

Summary. A rapid bioassay for diphenamid is described, based on differential elongation of oat roots after 48 h incubation, which can be used to assess the potency of diphenamid in solution or in soil. In sorption experiments using a slurry technique with soil: water ratios of 1: 2, 1: 3 and 1: 4, the bioactivity of the supernatant was similar for adsorption and release processes. The influence of soil characteristics on the bioactivity of diphenamid was determined by oat response in soil with herbicide and by oat bioassay on the supernatant after equilibration with soil. The results of direct and indirect assays corroborated each other and indicated that the organic matter content of the soil was the main factor affecting bioactivity.
GERMINATION OF SEEDS AND EMERGENCE OF SEEDLINGS OF AGROPYRON REPENS (L.) BEAUV.
Authors: WILLIAMS E. D.
Published: July 2006

Seeds of Agropyron repens (L.) Beauv, have little innate dormancy and germinate mainly during autumn, but germination may be delayed by cold, inadequate moisture or deep burial. Seedlings emerged from all viable seeds sown 5 cm deep but from only 4% of those 10 cm deep. Many seeds are viable when green and immature. At Rothamsted, spike emergence and flowering were earlier in 1970 than in 1968 and 1969 but more seeds became viable more rapidly in 1969. Higher temperatures in May and early June in 1970, and after flowering in 1969, probably account for most of these differences. Germination is facilitated by a diurnal alternation of temperature, but more old than young seeds can germinate at a constant temperature.
AMINO‐ACID COMPOSITION OF GRAIN PROTEIN FROM WHEAT AND BARLEY TREATED WITH 2,4‐D*
Authors: PELLETT P. L. , SAGHIR A. R.
Published: July 2006

Wheat and barley treated with the butoxyethyl ester of 2,4‐D at 2, 4 and 8 kg/ha (a.e.) at the jointing stage of growth were analysed for the amino‐acid composition of the protein of the grain. A slight decrease in the threonine and arginine, and an increase in the proline content of wheat protein were observed. In barley, only methionine showed a slight increase as a result of herbicide treatment. No significant difference in the amino‐acid composition of the protein was found in grain from hand‐weeded and un‐weeded plots. High doses of 2,4‐D may increase the protein percentage, but have only a very minor effect on the amino‐acid composition of the protein.
UNTERSUCHUNGEN ÜBER AUFNAHME UND TRANSLOKATION VON 14C‐MARKIERTEN HERBIZIDEN IN AGROSTEMMA GITHAGO L. UND TUSSILAGO FARFARA L.
Authors: SANAD A. J.
Published: July 2006

Studies of the uptake and translocation of 14C‐labelled 2, 4‐D, MCPA and aminotriazole in Agrostemma githago L. and Tussilago farfara L. clarified the behaviour of the herbicides in both species.

In A. githago, MCPA was more freely mobile than 2,4‐D after application to the leaf; it was distributed in the plant more rapidly and in greater quantity. Similarly, following root uptake MCPA was transported in the shoot in greater amounts than was 2,4‐D. There is a clear relationship between the susceptibility of A. githago to MCPA and the mobility of the herbicide in the plant.

In T. farfara, 2,4‐D and aminotriazole applied to the leaves were equally well absorbed and relatively rapidly translocated. During the period up to 72 h the amounts of herbicide in the plant increased to similar levels; after that, 14C activity in plants treated with 2,4‐D fell slightly whereas there was further accumulation of aminotriazole. Following uptake through the roots, translocation and accumulation in the leaves were considerably greater with aminotriazole than with 2,4‐D. The lack of accumulation of 2,4‐D could be a factor in the resistance of T. farfara to this herbicidie.

Recherches sur l'absorption et la migration d'herbicides marqués au
14
C dans Agrostemma githago L. et Tussilago farfara L.