bluuebunny/crossref_metadata_2025 huggingface dataset:
Chemical Versus Microbial Decomposition of Amitrole in Soil
Authors: Kaufman D. D. , Plimmer J. R. , Kearney P. C. , Blake J. , Guardia F. S.
Published: June 2019

Degradation of 3-amino-l,2,4-triazole-5-C14 (amitrole-5-C14) in autoclaved, potassium azide, ethylene oxide, and dry-heat sterilized soil was compared with that observed in nonsterile soils by measuring evolved C14O2. Amitrole degradation occurred in azide and ethylene oxide-sterilized and nonsterile soils but not in autoclaved soils. Only slight degradation occurred in autoclaved soil re-inoculated with mixed cultures of soil microorganisms isolated from soil in which amitrole had been rapidly degraded. Addition of EDTA-Na to nonsterile and ethylene oxide sterilized soils reduced amitrole degradation. Addition of organic amendments to amitrole treated soil stimulated microbial activity but reduced amitrole degradation. Addition of specific metallic salts to certain soils increased the rate of amitrole degradation. Amitrole degradation occurred rapidly in several free radical generating chemical systems. These results and additional observations indicate that amitrole degradation, at least in three soils examined, was largely a chemical process, and that microbial involvement was only indirect.
Incorporated Vernolate and Other Weed Control Treatments for Peanut Production
Authors: Upchurch R. P. , Selman F. L. , Webster H. L.
Published: June 2019

Fifteen herbicidal treatments were evaluated for weed control effectiveness in peanut (Arachis hypogaeaL.) culture at three locations in the peanut production area of eastern North Carolina during 1964 and 1965. Delayed preemergence treatments of 4,6-dinitro-o-sec-butylphenol (DNBP) alone and in combination withO-(2,4-dichlorophenyl)O-methyl isopropylphosphoroamidothioate (DMPA) were superior to conventional herbicidal and non-herbicidal control methods as were single and multiple incorporated treatments ofS-propyl dipropylthiocarbamate (vernolate). A single postplant vernolate treatment incorporated 1 in deep provided weed control superior to that obtained for single preplant vernolate treatments incorporated 1 in or 3 in deep. Increased weed control and increased peanut safety were obtained from 2.5 lb/A of vernolate by incorporating treatments at 0, 7, and 14 days after planting rather than by using a single application. This multiple treatment was the optimum one evaluated and provided 53 days of control and required 10 hr/A of hoeing time.
Quantitative Extraction of Fluometuron from Water Samples by n-Pentane
Authors: Davidson J. M. , Rieck C. E. , Santelmann P. W.
Published: June 2019

n-Pentane was used to extract 3-(m-trifluoromethylphenyl)-1,1-dimethylurea (fluometuron) from soil-water samples. The microgram quantity of fluometuron in the n-pentane was measured at a wavelength of 242 mμ with an ultraviolet spectrophotometer and this measurement related to the fluometuron concentration in the soil-water sample. No measurable interference was noted in the n-pentane after the extraction of fluometuron from the soil-water samples. The procedure was developed for extracting and quantitatively determining fluometuron in soil-water samples.
Alteration of Transpiration and Dry Matter with Atrazine
Authors: Graham James G. , Buchholtz K. P.
Published: June 2019

Root applications of 9.0 μM 2-chloro-4-ethylamino-6-isopropylamino-s-triazine (atrazine) to soybean plants (Glycine max (L.) Merr., var. Chippewa) for 4 hr significantly reduced their transpiration rates. Similar reductions in transpiration rate were elicited by foliar applications of 900 μM. All atrazine treatments that reduced transpiration prevented dry weight accumulation by the plants and increased plant hydration. Root additions of glucose to de-rooted plants treated with atrazine had no influence on the transpiration reduction due to atrazine treatment but caused an increase in dry weight accumulation. There was a rapid accumulation of 14C-atrazine in the roots of the soybean plants from the culture solution with subsequent movement to the leaves. Leakage of 14C-atrazine out of the roots into the water medium after treatment termination was observed.
Movement and Metabolism of CIPC in Resistant and Susceptible Species
Authors: Prendeville G. N. , Eshel Y. , James C. S. , Warren G. F. , Schreiber M. M.
Published: June 2019

Sublethal concentrations of isopropyl N-(3-chlorophenyl)- carbamate (CIPC) labeled with 14C in the ring or side chain were applied to all leaves present or to the roots of redroot pigweed (Amaranthus retroflexus L.), pale smartweed (Polygonum lapathiofolium L.), and parsnip (Pastinaca sativa L.). These species were selected because of their different susceptibilities to CIPC. The herbicide did not move out of the treated leaves in pigweed and smartweed and only slightly in parsnip in 21 days. In root treatment (3 days), the herbicide moved to all plant parts and the extent of movement was essentially the same in all species. Water soluble metabolites, which differed in Rf values were extracted from all three species. The metabolites apparently were not the result of cleavage of the CIPC molecule, but were more likely conjugates of CIPC with natural plant component(s). Very little 14CO2 was released by any of the species in 3 days. These data indicate that differences in movement and metabolism are not sufficient to account for the different susceptibilities of these three plant species.
Assessing Compatibility of Herbicides and Nitrogen Solutions
Authors: Klosterboer A. D. , Bardsley C. E.
Published: June 2019

A technique was developed for evaluating the stability of a herbicide suspended in nitrogen solutions of varying molarity. Dispersion stability is expressed as the difference in specific gravity (D value) between a salt solution + herbicide and the salt solution alone using a Westphal balance. The lower the D value, the less herbicide in suspension. Even very low molar solutions significantly lowered the D value. Further, the lower the percent active ingredient in the herbicide the more effectively the surfactants, and possibly other components of the formulated product, offset the adverse effect of salt on dispersion stability.
Influence of Paraquat on Seed Germination
Authors: Appleby Arnold P. , Brenchley Ronald G.
Published: June 2019

Three experiments were conducted in the greenhouse to study the effect of 1,1′-dimethyl-4,4′-bipyridinium salt (paraquat) when sprayed directly on seeds at the soil surface. Germination of alfalfa (Medicago sativa L., var. DuPuit) and red clover (Trifolium pratense L., var. Kenland) was not affected at 1 1b/A paraquat, but germination of Kentucky bluegrass (Poa pratensis L., var. Newport) and perennial ryegrass (Lolium perenne L., var. Linn) was severely reduced at that rate. A protecting layer of soil approximately 0.25 inch thick was completely effective in protecting the seeds from the effect of paraquat. Germination of seven other grass species was reduced by 0.5 1b/A paraquat.
Influence of Picloram Granules and Sprays on Whitebrush
Authors: Meyer R. E. , Riley T. E.
Published: June 2019

Whitebrush (Aloysia lycioides Cham.) near Llano and Marble Falls, Texas was treated at 19 dates with broadcast applications of the potassium salt of 4-amino-3,5,6-trichloropicolinic acid (picloram) as the 2% granules. At Llano, the average percentages of whitebrush plants killed with 1, 2, and 4 lb/A rates of picloram granules at five dates were 18, 52, and 87; however, at three dates, the 3 lb/A treatment killed 98% of the plants. Picloram granules were applied at 15 dates at Marble Falls where 1, 2, 3, and 4 lb/A rates averaged 17, 43, 68, and 79% of the whitebrush plants killed, respectively. Picloram was most toxic when applied during the cooler months, particularly when application was soon followed by rains. Broadcast sprays of the potassium salt of picloram were included at two dates and were more effective than granules. Most individual whitebrush plants were killed by one-third tablespoon of the 10% granule, or by 2 tablespoons of the 2% granule of picloram applied in an area 2 ft in diam at the base of the stem.
Longevity of Dodder Control by Soil-Applied Herbicides in the Greenhouse
Authors: Dawson J. H.
Published: June 2019

Isopropylm-chlorocarbanilate (chlorpropham) at 6 lb/A, the standard treatment, usually controlled dodder (Cuscutaspp.) completely for 3 to 5 weeks. Of 27 other herbicides compared with chlorpropham, seven controlled dodder completely for longer periods (6 to 18 weeks), and nine for comparable or slightly shorter periods. Eleven controlled dodder only partially or completely for a period shorter than that from chlorpropham. The period of dodder control from chlorpropham was doubled whenp-chlorophenylN-methylcarbamate at 1.5 lb/A was included with it.
Antagonistic Responses with Combinations of Carbamate and Growth Regulator Herbicides
Authors: Prendeville G. N. , James C. S. , Warren G. F. , Schreiber M. M.
Published: June 2019

Antagonistic responses were noted on sorghum (Sorghum vulgarepers.) and giant foxtail (Setaria faberiiHerrm.) using preemergence combinations of (2,4-dichlorophenoxy)acetic acid (2,4-D) and the carbamatesS-ethyl dipropylthiocarbamate (EPTC), isopropylm-chlorocarbanilate (chlorpropham), and 2-chloroallyl diethyldithiocarbamate (CDEC). Combinations of EPTC and (2,4,5-trichlorophenoxy)acetic acid (2,4,5-T) or 3,6-dichloro-o-anisic acid (dicamba) gave similar results. Effects of these combinations were mainly additive on four dicotyledonous species. Combinations of 2,4-D andN-1-naphthylphthalamic acid (naptalam) also were antagonistic on sorghum and giant foxtail but were additive on the remaining species. Eight other herbicide combinations were mainly additive on all six species.
Behavior of Pyrazon in Soil
Authors: Frank R. , Switzer C. M.
Published: June 2019

The disappearance of 5-amino-4-chloro-2-phenyl-3(2H)-pyridazinone (pyrazon) from soil was studied using Brassica species for bioassay and the spectrophotometer and chromogenic reagents for chemical determination. Loss of pyrazon from soil appeared to be an exponential function of time characteristic of the activity of soil microorganisms. On the other hand, non-biological degradation appeared negligible. Leaching of pyrazon appeared to be insignificant or minor. The greater part of the herbicide remained in the top 3 inches of soil.
Metabolism of Pyrazon in Sugar Beets and Soil
Authors: Stephenson G. R. , Ries S. K.
Published: June 2019

Sugar beets (Beta vulgarisL., var. MSU 126 × 5460) were treated with 5-amino-4-chloro-2-phenyl-3(2H)-pyridazinone (pyrazon) applied to the soil. The pyrazon was labeled with either3H in the phenyl ring, or with14C at the 4 and 5 positions of the pyridazinone ring. The disappearance of pyrazon and the appearance of metabolites in the soil and shoots were examined 1, 2, 4, 6, 8, 12, and 16 weeks after treatment. The total recoverable radioactivity decreased with time, but there was a greater loss of3H-labeled compounds than14C-labeled compounds from the soil. Thin-layer chromatography of the soil and shoot extracts revealed the presence of one metabolite in the soil and three metabolites in the plant. By co-chromatography with known pyrazon derivatives and by comparison of the labeling (14C,3H, or both), the metabolites in the shoot were identified as N-(2-chloro-4-phenyl-3(2H)-pyridazinone)-glucosamine (hereinafter referred to as N-glucosyl pyrazon), 5-amino-4-chloro-3(2H)-pyridazinone (hereinafter referred to as ACP), and ACP-complex. The other moiety in the ACP-complex was not identified. The metabolite in the soil was identified as ACP, and was detectable 2 weeks prior to its appearance in the shoot, suggesting that it was absorbed from the soil.
Absorption and Translocation of Pyrazon by Plants
Authors: Frank R. , Switzer C. M.
Published: June 2019

Pyrazon (5-amino-4-chloro-2-phenyl-3(2H)-pyridazinone) was absorbed by the roots of both common lambsquarters (Chenopodium albumL.) and sugar beets (Beta vulgarisL.) and translocated in an acropetal direction to all parts of the plant. Common lambsquarters plants accumulated greater amounts of3H-pyrazon per gram of tissue than did sugar beet plants and this was especially true of leaf tissues. Translocation into the leaves of both species occurred equally into mature and developing leaves. Neither basipetal nor acropetal translocation of pyrazon occurred following leaf applications of3H-pyrazon. Pyrazon accumulated in the leaves of common lambsquarters, but it was metabolized when absorbed into sugar beets. Roots, petioles, and leaf blades of beets rapidly metabolized pyrazon while only roots metabolized pyrazon in common lambsquarters. Selectivity of pyrazon appeared to be associated with the rate of metabolic breakdown occurring in the leaf. Accumulations occurred in the susceptible common lambsquarters plant while metabolism kept pace with uptake in the leaves of the tolerant sugar beet plant.
Response of Soybeans to 2,4-D, Dicamba, and Picloram
Authors: Wax L. M. , Knuth L. A. , Slife F. W.
Published: June 2019

Field experiments were conducted for 2 years at Urbana, Illinois, to evaluate the response of soybeans (Glycine max (L.) Merr., var. Harosoy 63) to soil and foliar applications of 3,6-dichloro-o-anisic acid (dicamba), 4-amino-3,5,6-trichloropicolinic acid (picloram), and (2,4-dichlorophenoxy)acetic acid (2,4-D). Soil incorporated applications of 2,4-D or dicamba at rates up to 8 oz/A or 4 oz/A, respectively, just before planting soybeans did not reduce soybean yields significantly. Picloram, applied under the same conditions, reduced soybean yield almost 40% at ½ oz/A. Picloram at rates from ½ to 2 oz/A caused slight to moderate leaf malformation on soybeans planted the following year but did not reduce yield. Foliar applications of 2,4-D up to 2 oz/A on soybeans had little effect on yield when applied at the prebloom stage and only slightly reduced yield when applied during flowering. Dicamba and picloram injured soybeans at the prebloom stage considerably more than did 2,4-D. Dicamba and picloram severely restricted soybean development, and reduced yield markedly when applied during flowering; ½ oz/A of dicamba or ⅛ oz/A of picloram reduced soybean yield about 50%.
Factors Affecting Growth of Rooted Aquatics in a River
Authors: Peltier W. H. , Welch E. B.
Published: June 2019

During 1967, field studies on the Holston River and in the laboratory produced evidence that excessive aquatic plant growths are not soley related to the presence of large amounts of nutrients in water. Factors contributing to growth were the amount of nutrients in sediments, water depth, and turbidity. Water depth and turbidity influence the amount of light which penetrates the water and is available for the growth of rooted plants.
Adsorption ofs-Triazines by Soil Organic Matter
Authors: Weber J. B. , Weed S. B. , Ward T. M.
Published: June 2019

The adsorption of sevens-triazines from aqueous solutions by organic soil colloids was determined at pH levels from 1.0 to 5.2. Maximum adsorption occurred at pH levels in the vicinity of the pKAvalues of the respective compounds. The amounts adsorbed were dependent upon the molecular structures of the compounds and the pH of the suspension and were, in order of decreasing adsorption, as follows: 2-methoxy-4,6-bis(diethylamino)-s-triazine (hereafter referred to as tetraetatone) = 2,4-bis(isopropylamino)-6-methylmercapto-s-triazine (prometryne) = 2-hydroxy-4,6-bis(isopropylamino)-s-triazine (hereafter referred to as hydroxypropazine) > 2-methoxy-4-diethylamino-6-ethylamino-s-triazine (hereafter referred to as trietatone) > 2-methoxy-4,6-bis(isopropylamino)-s-triazine (prometone) > 2-methoxy-4,6-bis(ethylamino-s-triazine (simetone) > 2-chloro-4,6-bis(isopropylamino-s-triazine (propazine). Approximately 52% of the prometone adsorbed by the organic matter was desorbed with two extractions of 0.1N NaCl. It was concluded that the adsorption of thes-triazines was due to complexing of the triazine molecules with functional groups on the organic colloids and/or adsorption ofs-triazine cations by ion exchange forces.
Paraquat for Weed Control Prior to Establishing Legumes
Authors: Linscott D. L. , Akhavein A. A. , Hagin R. D.
Published: June 2019

Land was prepared conventionally in early spring for the planting of small seeded legumes. Planting was delayed to allow emergence of weeds. We applied 1,1'-dimethyl-4,4'-bipyridinium salts (paraquat) and planted legumes immediately afterwards. Stage of weed growth, time of herbicide application, rate of chemical applied, and the methods of seeding were variables imposed. Paraquat (plus surfactant) applied at 1.1 and 2.2 kg/ha to emerged weeds prior to the seeding of legumes controlled quackgrass [Agropyron repens(L.) Beauv.] sufficiently to allow excellent establishment of alfalfa (Medicago sativaL.) and birdsfoot trefoil (Lotus corniculatusL.). A paraquat application delayed until yellow nutsedge (Cyperus esculentusL.) was at least 10 cm in height, followed by a disking, controlled the sedge sufficiently to allow legume establishment. For annual weed control, 0.3% kg/ha of paraquat was sufficient. Drilling as a method of seeding gave better legume stands than did surface-seeding techniques.
Herbicide Equilibrium in Soils in Relation to Soil Water Content
Authors: Green R. E. , Obien S. R.
Published: June 2019

The concept of herbicide partition into adsorbed and solution phases in the soil was utilized to predict the effect of soil water content on the concentration of herbicide in solution. Calculated predictions based on measured partition coefficients and water contents were tested experimentally by equilibrating 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine (atrazine) with soil from three horizons of a latosolic soil at four water contents (45 to 60%). The effects of adsorption and water content were predicted with reasonable accuracy when only that water held at tensions less than 15 bars was considered available for equilibration with the applied herbicide. Only on low adsorption soils will water content variations alter significantly herbicide concentration in the soil solution. The principal effect of soil water content on herbicide phytotoxicity probably is associated with herbicide transport, which is more sensitive to changes in water content than is the concentration of herbicide in soil solution.
Effect of Light on the Herbicidal Activity of Some Amiben Derivatives
Authors: Isensee A. R. , Plimmer J. R. , Turner B. C.
Published: June 2019

Residual herbicidal action of 3-amino-2,5-dichlorobenzoic acid (amiben), the methyl ester of amiben, 3-acetamido-2,5-dichlorobenzoic acid (N-acetyl amiben), 3-propionamido-2,5-dichlorobenzoic acid (N-propionyl amiben), 3-benzamido-2,5-dichlorobenzoic acid (N-benzoyl amiben), and the methyl ester of N-benzoyl amiben after 0, 1, 2, 4, and 6 hr irradiation was measured by oats (Avena sativa L., var. Markton) bioassay. In a greenhouse study, amiben and N-benzoyl amiben were applied to the soil surface, exposed to sunlight for 7.5 hr, and similarly bioassayed. Amiben, the methyl ester of amiben, and N-acetyl amiben lost 40 to 60% of their original herbicidal activity after 2 to 4 hr irradiation in the laboratory. N-benzoyl amiben and its methyl ester retained over 90% of their activity after 6 hr irradiation. Solar illumination reduced the herbicidal activity of amiben applied to the surface of wet soil by 11 to 14% but had no effect on N-benzoyl amiben. On a dry soil, the losses of amiben and N-benzoyl amiben were not significant.
Effects of Herbicides on RNA and Protein Syntheses
Authors: Moreland D. E. , Malhotra S. S. , Gruenhagen R. D. , Shokraii E. H.
Published: June 2019

Effects of 22 herbicides on the synthesis of RNA and protein were investigated in excised tissues. The assays measured ATP and orotate incorporation into RNA, leucine incorporation into protein, and the gibberellin-controlled induction of a-amylase Statistical analysis of the average responses measured in the four assays suggested that 14 of the herbicides inhibited RNA and protein biosynthesesin vivo.The most inhibitory chemicals were 4-hydroxy-3,5-diiodobenzonitrile (ioxynil), 2-sec-butyl-4,6-dinitrophenol (dinoseb), 3',4'-dichloropropionanilide (propanil), 2,3,5-trichloro-4-pyridinol (pyriclor), and isopropylm-chlorocarbanilate (chlorpropham). The activity of an RNA polymerase isolated from corn(Zea maysL.) tissue was inhibited maximally at approximately 20% by ioxynil, dinoseb, and pyriclor. Hence, interference with RNA polymerase, which performs a pivotal role in RNA and protein biosyntheses, does not fully account for all inhibitions.
Factors Influencing the Phytotoxicity of Chloroxuron
Authors: Carlson Wayne C. , Wax L. M.
Published: June 2019

The phytotoxicity of 3-[p-(p-chlorophenoxy)phenyl]-1,1-dimethylurea (chloroxuron) usually decreased as the stage of growth of five weed species at treatment increased. Giant foxtail (Setaria faberiiHerrm.), velvetleaf (Abutilon theophrastiMedic.), and the cotyledonary stage of cocklebur (Xanthium pensylvanicumWallr.) were most resistant to the herbicide. Ivyleaf morningglory (Ipomoea hederacea(L.) Jacq.) and jimsonweed (Datura stramoniumL.) were more susceptible to chloroxuron. Soybean (Glycine max(L.) Merr.) seemed less susceptible at the cotyledonary stage than at later stages. Phytotoxicity on both weeds and soybeans was increased by increased temperature and relative humidity following chloroxuron application. The phytotoxicity of chloroxuron also was increased by simulated rainfall in greenhouse studies.
Histochemical Studies in Weed Seed Dormancy
Authors: Biswas P. K. , Chakrabarti A. G. , Collins H. A. , Bettis R. B.
Published: June 2019

Seeds of Pennsylvania smartweed (Polygonum pennsylvanicum L.), quackgrass (Agropyron repens L. Beauv.), yellow foxtail (Setaria lutescens L. Beauv.), and wild mustard (Brassica kaber (DC) L. C. Wheeler) were studied to determine if histochemical differences existed in seeds of dormant and non-dormant weed species. The hulls (seedcoat) of yellow foxtail and seedcoats of wild mustard and quackgrass had distinct inhibitory effects on germination. Endosperm tissue in wild mustard and Pennsylvania smartweed also inhibited embryo growth in these species. Results obtained from specific staining techniques on seed sections 10μ thick for identification and determination of distribution of proteins, lipids, carbohydrates, and lignin in dormant and germinating seeds suggested that possible mechanisms of seed dormancy are: (a) lower protein content in seed tissues of wild mustard; (b) higher lignification in hull of foxtail and endosperm of Pennsylvania smartweed; (c) lower sterol content in embryo of wild mustard and Pennsylvania smartweed; (d) high cellulose content in hull of foxtail and endosperm of Pennsylvania smartweed. Excised embryos from dormant seeds of Pennsylvania smartweed showed a measurable amount of growth in White's standard agarnutrient. Germinating embryos of wild mustard and quackgrass were larger than those in dormant seeds; therefore, immaturity of embryos might contribute to dormancy in these species.
Influence of Soil-Moisture Content on the Bioactivity of Picloram
Authors: Grover R.
Published: June 2019

A somewhat modified version of Lambert's quantitative treatment of the influence of soil-moisture content on herbicidal activity has been applied to 4-amino-3,5,6-trichloropicolinic acid (picloram) behavior in soil. The bioactivity of picloram decreased as the soil-moisture content was increased. This was due to the effect of varying soil-moisture levels on the concentration of picloram in the soil-water phase.
Functional Environment of Downy Brome Communities in Relation to Weed Control and Revegetation
Authors: Evans Raymond A. , Holbo H. Richard , Eckert Richard E. , Young James A.
Published: June 2019

We measured some of the more important biologic and microclimatic parameters of the functional environment of downy brome (Bromus tectorumL.) communities during the establishment period of seedlings of intermediate wheatgrass (Agropyron intermedium(Host) Beauv., var. Amur). These measurements were made in relation to weed control and seeding treatments. Weed growth and establishment of replacement vegetation were directly related to available soil moisture and favorable temperatures in the immediate environment of growing plants. Lack of available soil moisture during critical periods of the growing season was the major deterrent to seeding success. The limited precipitation stored as soil moisture was available to perennial grass seedlings where weeds were controlled. Without weed control, growth of downy brome preempted the effective precipitation, and moisture became limiting for growth of perennial grass seedlings. Seeding in furrows, along with weed control, further improved moisture conditions for the seedlings. Also, use of furrows enhanced seedling growth by lowering maximum air and soil temperatures in the seedlings' immediate environment.
Influence of Soybean Seed Size on Response to Atrazine
Authors: Andersen Robert N.
Published: June 2019

In the greenhouse, we examined approximately 2,700 strains of soybeans [Glycine max (L.) Merr.] for response to 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine (atrazine), a herbicide which inhibits photosynthesis. Duration of survival when grown in soil containing 0.84 kg/ha was the initial selection criterion. Strains thus selected as most tolerant and most susceptible were grown then for 3 to 3 ½ weeks in soil containing 0.45 kg/ha of atrazine. The dry weight of shoots expressed as a percentage of each strain's own untreated check was used to measure the strains' tolerance of atrazine. Tolerance, thus measured, generally increased as seed size increased. Regression analysis indicated that 80% of the variation in response was attributable to variation in seed size. We suggest the possibility of minimizing soybean injury from atrazine (and perhaps other herbicides) by planting large seed.
Absorption and Translocation of14C-Labeled 2,4-D and Picloram in Field Bindweed
Authors: Agbakoba Chuma S. O. , Goodin J. R.
Published: June 2019

Absorption and translocation of (2,4-dichlorophenoxy)-acetic acid (2,4-D) and 4-amino-3,5,6-trichloropicolinic acid (picloram) were measured in defoliated and intact field bindweed (Convolvulus arvensisL.) plants. Radioactivity was applied as 5 μl of triethylamine salts of 2,4-D and picloram with an activity of 0.15 μc to a middle leaf in intact and partially-defoliated plants. After treatment for 96 hr,14C-activity in untreated leaves, stems, growing tips, and roots was measured. Removal of all leaves significantly reduced absorption but not translocation of both 2,4-D and picloram. A greater percentage of the applied picloram than 2,4-D was absorbed in all treatments. Translocation of14C of both 2,4-D and picloram was greater when (a) upper and lower leaves were removed, (b) upper leaves only were removed, and (c) lower leaves only were removed than (d) when plants were intact. Removal of lower (older) leaves reduced translocation more than removal of upper (younger) leaves.
Comparisons of Dihydroxybenzenes and Paraquat
Authors: Hogue E. J. , Warren G. F.
Published: June 2019

Although similar in mode of action, 1,2-dihydroxybenzene (catechol) and 1,1′-dimethyl-4,4′bipyridinium ion (paraquat) at different levels were required to kill plants. Both chemicals were fast-acting, they both required light to be active, and herbicides that inhibit photosynthesis protected the plants temporarily against the action of both compounds. Paraquat and catechol had additive effects on black nightshade (Solanum nigrum L.) but not on redroot pigweed (Amaranthus retroflexus L.). Catechol protected redroot pigweed against the action of paraquat.
Control of Kochia in Sugarbeets With Benzadox
Authors: Weatherspoon D. M. , Schweizer E. E.
Published: June 2019

Benzadox [(benzamidooxy)acetic acid] applied at 1, 2, 3, and 4 lb/A as a postemergence treatment controlled kochia [Kochia scoparia(L.) Schrad.] selectively in sugarbeets (Beta vulgarisL.). Control increased as the rate of benzadox increased, but some kochia survived at the 4-lb/A rate. Competition from these plants reduced the yields of sugarbeet roots and sucrose. Where surviving kochia plants were removed by hand 7 weeks after emergence, all sugarbeets treated with benzadox yielded as well as the hand-weeded checks. In growth chamber studies, the activity of benzadox was increased by temperature and decreased by simulated rain which occurred within 4 hr following application. Under a temperature regime of 70 F day and 40 F night, if simulated rain was delayed for 8 hr, the control of kochia was identical to that obtained where no simulated rain followed treatment. The growth chamber studies confirmed our results with the performance of benzadox under different environmental conditions in the field.
Dodder Control in Alfalfa by Dichlobenil
Authors: Dawson J. H.
Published: June 2019

The herbicide, 2,6-dichlorobenzonitrile (dichlobenil), applied to the soil surface at 2 lb/A controlled dodder (Cuscutaspp.) and other weeds for 4 to 6 weeks in the field, and did not injure established alfalfa (Medicago sativaL.) significantly. Soil incorporation increased the herbicidal effect of dichlobenil on alfalfa and dodder, but alfalfa injury was increased more than dodder control. Dichlobenil was effective when applied just before sprinkler irrigation, or on moist soil after irrigating. In the greenhouse, dichlobenil vapors moved from a wettable powder formulation mixed with moist soil or from granules on the surface of moist soil, and killed dodder in adjacent untreated soil.
Phytotoxicity of Bensulide and Trifluralin in Several Soils
Authors: Menges R. M. , Hubbard J. L.
Published: June 2019

Seedlings of 19 plant species were grown in soils containing 0 to 1,000 ppm ofO,O-diisopropyl phosphorodithioateS-ester withN-(2-mercaptoethyl)benzenesulfonamide (bensulide) or 0 to 100 ppm ofa,a,a-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin) to determine phytotoxicity. Standard growth curves were constructed. The concentration of bensulide required to reduce the growth of shoots 50% (GR50) ranged from 1 ppm with barnyardgrass (Echinochloa crusgalli(L.) Beauv.) to more than 1,000 ppm with carrot (Daucus carotaL., var. Long Imperator). Several plant species were more sensitive to bensulide in a Hidalgo sandy loam (pH 8.1) than in other soils including a Delfina loamy fine sand (pH 6.0). The concentration of trifluralin required to reduce the growth of shoots 50% (GR50) was not markedly affected by soil texture and ranged from 0.1 ppm with German millet (Setaria italica(L.) Beauv.) to more than 100 ppm with Long Imperator carrot. The standard growth curves have been used to quantify herbicidal activities in field soils.
Selectivity, Movement, and Persistence of Soil-Incorporated Herbicides in Carrot Plantings
Authors: Menges R. M. , Hubbard J. L.
Published: June 2019

The comparative performances of several herbicides incorporated 2.5 cm deep and unincorporated in furrow-irrigated soil were studied in four field experiments. Among eight herbicides evaluated,a,a,a-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin) was the most effective herbicide and controlled redroot pigweed (Amaranthus retroflexusL.), Palmer amaranth (Amaranthus palmeriS. Wats.), common purslane (Portulaca oleraceaL.), and barnyardgrass (Echinochloa crusgalli(L.) Beauv.) when incorporated, without reduction of yield in carrots (Daucus carotaL., var.saliva, cv. Long Imperator). Trifluralin andO,O-diisopropyl phosphorodithioateSester withN-(2-mercaptoethyl)benzenesulfonamide (bensulide) gave consistently good results in all years although soil temperatures and evaporative losses of water were variable. Bioassays indicated and gas-liquid chromatographic (hereinafter referred to as GLC) assays confirmed that rainfall moved bensulide and trifluralin 2.5 cm downward in soil, and that dimethyl tetrachloroterephthalate (DCPA) was not moved below the original depth of incorporation in soil. GLC assays were most sensitive but generally agreed with bioassays of trifluralin-treated soils. Under high temperatures, infrequent rainfall, and furrow irrigation, the half-life of DCPA and trifluralin activities was 3 weeks, with no biological activity after 7 months. The half-life of bensulide activity was 6 months, with no biological activity after 22 months.
Persistence and Degradation of Pyrazon in Soil
Authors: Smith D. T. , Meggitt W. F.
Published: June 2019

Based on bioassays of soil samples from field plots, the rate of disappearance of 5-amino-4-chloro-2-phenyl-3 (2H)-pyridazinone (pyrazon) was estimated with a multiple regression equation. Within a limited geographic region, pyrazon residues were directly related to the organic matter content of soil and inversely related to rainfall during the growing season. The bacteria population increased with the presence of pyrazon in soil at soil temperatures ranging from 4.5 to 29.5 C, indicating a wide capability of microbiological utilization of the herbicide in soil. There was no evidence that soil bacteria or actinomycetes were adversely affected by pyrazon. Thin layer chromatography of ethanol extracts of soil containing 3H-phenyl-labeled and 14C-pyridazinone-labeled pyrazon revealed that pyrazon is dephenylated to 5-amino-4-chloro-3-pyridazinone. In a sandy loam soil, less than 10% of the herbicide was degraded to 5-amino-4-chloro-3-pyridazinone after 10 weeks at 21 C.
Changes in Dormancy and Viability of Weed Seeds in Soils
Authors: Taylorson R. B.
Published: June 2019

Seeds of several weed species, each with initially known responses to light and temperature, were buried in soil in an open field at 2.5, 7.6, and 15.2-cm depths during November. At 3-month intervals during the following year, the seeds were recovered in the dark and reexamined for their response to light and temperature, and their viability. Loss in viability occurred fastest with seeds having little initial dormancy and with shallow placement of seeds. Phytochrome was important in controlling germination of the recovered weed seeds, and manifested itself as an acquired type of dormancy, as well as an initial one. However, other factors in the soil environment appear to interact with the phytochrome system in the control of germination of weed seeds in soils.
Control of Yellow Rocket and White Cockle in Established Alfalfa
Authors: Hastings R. E. , Kust Cyril A.
Published: June 2019

Yellow rocket (Barbarea vulgarisR. Br.) was effectively controlled in established alfalfa (Medicago sativaL.) by September 15 applications of 2-chloro-4,6-bis(ethylamino)-s-triazine (simazine), 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine (atrazine), 3-tert-butyl-5-chloro-6-methyluracil (terbacil), and 2-sec-butylamino-4-ethylamino-6-methoxy-s-triazine (hereinafter referred to as GS 14254). White cockle (Lychnis albaMill.) was more difficult to control, but simazine was the most effective herbicide. Herbicide applications in early October reduced reserve nonstructural carbohydrate accumulations in roots of yellow rocket by November 15 but not in white cockle. Alfalfa yields were not reduced by two consecutive autumn applications of the herbicides at rates that provided adequate control of yellow rocket and white cockle.
Granular vs. Liquid Formulations of Picloram, HRS 587, Fenac, and 2,3,6-TBA for Control of Field Bindweed
Authors: Lavake Dwane E. , Wiese Allen F. , Chenault E. Wayne
Published: June 2019

Better field bindweed (Convolvulus arvensisL.) control was obtained from granular formulations of 2,3,6-trichlorobenzyloxypropanol (hereinafter referred to as HRS 587), 4-amino-3,5,6-trichloropicolinic acid (picloram), (2,3,6-trichlorophenyl)acetic acid (fenac), and 2,3,6-trichlorobenzoic acid (2,3,6-TBA) than with equivalent amounts of liquid formulations. Two years after application, a granular formulation of picloram at 1 lb/A was as effective as a liquid formulation at 3 lb/A. One and 2 years after application, granular formulations of HRS 587, fenac and 2,3,6-TBA at 10 lb/A gave field bindweed control equal to that obtained with 20 lb/A of liquid formulations of these chemicals. Incorporation did not greatly affect the toxicity of either the liquid or granular formulations of the four herbicides. Increased effectiveness of granular formulations appeared to be associated with longer persistence in the soil.
Isoparaffinic Oil as a Carrier for Chlorpropham and Terbacil
Authors: Barrentine J. L. , Warren G. F.
Published: June 2019

The herbicides 3-tert-butyl-5-chloro-6-methyluracil (terbacil) and isopropyl m-chlorocarbanilate (chlorpropham) showed greatly enhanced activity on giant foxtail (Setaria faberii Herrm.) and ivyleaf morningglory (Ipomoea hederacea (L.) Jacq.) when applied in an isoparaffinic oil rather than water. The activity of terbacil was enhanced but to a lesser extent when crop oil was added to a water carrier at a concentration of 10%. In field trials, similar enhancement of terbacil and chlorpropham activity was obtained on several weeds. Onions (Allium cepa L., var. Spartan Gem) in the “loop stage” were moderately tolerant and carrots (Daucus carota L., var. Royal Chantenay) were highly tolerant to chlorpropham at 4 lb/A applied in the isoparaffinic oil. Peppermint (Mentha peperita L.) and spearmint (Mentha spicata L.) were tolerant to terbacil applied in the oil at rates sufficient to give good weed control. The oil alone had no injurious effects on onions, carrots, peppermint, or spearmint. This enhancement in activity in greenhouse and field studies appeared to be due to increased penetration as shown by washing, speed of killing plants, and tracer studies. Tracer studies showed that within 2 hr after application, the isoparaffinic oil increased the penetration of chlorpropham more than eightfold in ivyleaf morningglory and more than fourfold in giant foxtail compared to a water carrier. This increase in penetration was even more striking with terbacil. After 4 hr, penetration was increased over 16 times in ivyleaf morningglory and over 18 times in giant foxtail, when applied in the oil rather than acetone. Chlorpropham and terbacil were translocated to the shoot apex of ivyleaf morningglory only when they were applied in the oil.
Selective Action of Terbacil on Peppermint and Ivyleaf Morningglory
Authors: Barrentine J. L. , Warren G. F.
Published: June 2019

The herbicide 3-tert-butyl-5-chloro-6-methyluracil (terbacil) applied in an isoparaffinic oil caused, in susceptible ivyleaf morningglory (Ipomoea hederacea(L.) Jacq.), rapid and nearly complete inhibition of photosynthesis, from which it never recovered. Photosynthesis in peppermint (Mentha peperitaL.), a tolerant species, was decreased only temporarily. Terbacil was readily absorbed by leaves of both species; however, there was little or no movement out of the treated peppermint leaves. Terbacil was translocated out of the treated leaves of ivyleaf morningglory to the untreated leaves and shoot apex. It was metabolized in both species but at a higher rate in peppermint. Therefore, it appears that foliarly-applied terbacil may be bound in peppermint leaves and this, together with the higher rate of metabolism, may contribute to the tolerance of peppermint. Terbacil was readily taken up and translocated to the foliage of both species when applied to the roots. Again, it was metabolized in both plants but at a higher rate in peppermint. However, the rate of metabolism alone did not appear to be sufficient to account for peppermint tolerance to root-applied terbacil.
Effects of Paraquat and Light Regime on Quackgrass Growth
Authors: Akhavein A. A. , Linscott D. L.
Published: June 2019

We applied 1,1′-dimethyl-4,4′-bipyridinium ion (paraquat) to quackgrass (Agropyron repens L. Beauv.) at different stages of growth and subjected these treated plants to different light regimes. After paraquat and light treatment, foliage was removed and the reduction in regrowth was measured as evidence of paraquat movement and its effect on the regenerative potential of the rhizomes. Paraquat or a toxic metabolite moved in quantity from point of leaf application. Sufficient basipetal movement occurred in both the dark and light to significantly affect regrowth. As quackgrass plants matured and developed more foliage, the effect of paraquat treatment increased (i.e., the regrowth capacity of the plants and the regenerative ability of their rhizome buds decreased). A period of darkness (24 hr) after paraquat application and before exposure of treated plants to light did not affect numbers of plants killed but did decrease rate of regrowth. Treated quackgrass foliage showed extensive paraquat injury when placed in light for 48 to 72 hr after treatment; but only parts of treated leaves were killed. Leaving treated foliage intact greatly increased the number of plants killed.
Germination and Maturation of Chenopodium humile L.
Authors: Jordan L. S. , Jolliffe V. A.
Published: June 2019

Chenopodium humile L. did not germinate under laboratory conditions while the pericarp was intact. Scarification, leaching, ethanol, gibberellic acid, and thiourea stimulated germination. Germination was enhanced by moderate temperature (30 C), and long days. Factors which stimulated germination shortened the time between planting and maturation under short-day conditions but did not promote flowering which was absent under long-day growing conditions. Water stress did not affect germination but hastened maturation.
Emergence of Fourwing Saltbush After Spraying Shrubs by Picloram
Authors: Martin S. Clark , Shellhorn Samuel J. , Hull Herbert M.
Published: June 2019

Aqueous sprays of 4-ammo-3,5,6-trichloropicolinic acid (picloram) (1 lb aehg) were applied to individual plants in stands of burroweed (Haplopappus tenuisectus(Greene) Blake) and creosotebush (Larrea tridentata(DC.) Coville) August 27 to 31, 1965, to prepare the areas for seeding to fourwing saltbush (A triplex canescens(Pursh) Nutt.). By July 1967, 99% of the burroweed was dead, but 90% of the creosotebush was still alive. Samples of the surface ½ inch of soil, taken February 1, 1966, were planted to fourwing saltbush. Emergence and growth of fourwing saltbush were seriously reduced on soil taken from under the sprayed burroweed crowns. Growth of fourwing saltbush seedlings was retarded on soils from beneath sprayed creosotebushes, but emergence was not reduced significantly. The surface soil under sprayed burroweed crowns contained 0.11 ppm picloram 2 years after treatment, but the picloram test was negative on soils from the creosotebush area.
Validity of Evaluating Transformation of Primary Rhizomes in Yellow Nutsedge
Authors: Bendixen Leo E.
Published: June 2019

Rhizomes develop from the crowns of yellow nutsedge (Cyperus esculentus L.) shoots and the tips transform into shoots or tubers. Transformation of primary rhizomes developed by the original shoot of a plant is a valid index of plant response to treatment when compared with the transformation of all rhizomes (primary, secondary, tertiary, and others), developed by a plant under treatment.
Optimizing an Environmental Observatory Network Design Using Publicly Available Data
Authors: Villarreal Samuel , Guevara Mario , Alcaraz‐Segura Domingo , Vargas Rodrigo
Published: June 2019

There is a need to optimize resources for large‐scale environmental monitoring efforts, especially in developing countries. We tested a flexible framework to optimize the design (i.e., selection of study sites) of an environmental observatory network (EON) using publicly available data for Mexico. This country represents a challenge for designing EONs because of its megadiversity and large climate and ecological heterogeneity. We address three pervasive challenges for designing EONs: (1) How to characterize and delineate ecologically similar areas, (2) how to set geographic priorities to establish new representative study sites, and (3) how to assess the representativeness of current and potential new study sites. We used unsupervised cluster analysis to spatially delineate ecologically similar sampling domains. We identified the most representative sites within each domain using a conditioned Latin Hypercube‐sampling strategy. Finally, we demonstrated the applicability of this approach by assessing the spatial representativeness of the eddy covariance network in Mexico (i.e., MexFlux). At least 84 distributed sampling sites are needed to represent >45% of the spatial heterogeneity of gross primary productivity (GPP) dynamics (i.e., GPP_mean and GPP_cv) and evapotranspiration (ET) dynamics (i.e., ET_mean and ET_cv) at the national level. The current array of MexFlux only represents 3% of GPP and 5% of ET dynamics spatial variability at the national‐level, while the same number of sites organized under an optimal framework nearly doubled these estimates. Our framework is based on a data‐driven approach and publicly available sources of information, so it could be applied anywhere in the world.
Colorimetric determination of phenytoin using indoxyl sulfate capped silver nanoparticles
Authors: Khoubnasabjafari Maryam , Salari Rana , Samadi Azam , Jouyban-Gharamaleki Vahid , Jouyban Abolghasem
Published: June 2019

A simple and sensitive colorimetric probe based on aggregation of indoxyl sulfate capped silver nanoparticles was proposed for the detection of trace amounts of phenytoin.
Rolling and unrolling of graphene sheets via in situ generation of superparamagnetic iron oxide nanoparticles
Authors: Sathyan Meera , Jayaraj M. K. , John Honey
Published: June 2019

The role of magnetite nanoparticles in the scrolling and unscrolling of graphene sheets.
Eco-friendly and high-performance photoelectrochemical anode based on AgInS2 quantum dots embedded in 3D graphene nanowalls
Authors: Nong Jinpeng , Lan Guilian , Jin Weifeng , Luo Peng , Guo Caicheng , Tang Xiaosheng , Zang Zhigang , Wei Wei
Published: June 2019

An eco-friendly photoanode with improved PEC performance is proposed by embedding AgInS2 QDs into 3D GNWs.
Toxicity and multigenerational effects of bisphenol S exposure to Caenorhabditis elegans on developmental, biochemical, reproductive and oxidative stress
Authors: Xiao Xiang , Zhang Xiaowei , Zhang Caiqin , Li Jie , Zhao Yansheng , Zhu Ying , Zhang Jiayan , Zhou Xinghua
Published: June 2019

Bisphenol A (BPA) is a typical endocrine disruptor. Bisphenol S (BPS) has been widely used as a substitute for various plastic materials due to the limited application of BPA. However, it does not mean that BPS is a safe substitute due to the lack of effective evaluation of BPS. In this study, the clinical model of Caenorhabditis elegans (C. elegans) was used to study the effects of BPS on the locomotion behavior, growth, reproduction, lifespan and antioxidant system. Our study found that C. elegans exposed to 0.01 μM BPS could have significantly inhibited locomotion behavior and growth, as well as damaged reproductive and antioxidant systems and lifespan. It is interesting to note that in multi-generational exposure studies, we found that BPS exhibits complex genotoxicity. With the transmission to the offspring, BPS showed more significant inhibition of the head thrashes of the nematode, while the effect on the body bends and body length was gradually weakened. The effect of BPS on the brood size shows different rules according to different concentrations and offsprings. Therefore, the safety of BPS still needs further evaluation, especially the multi-generational genotoxicity.