bluuebunny/crossref_metadata_2025 huggingface dataset:
Persistence Pattern for Diuron and Linuron in Norfolk and Duplin Sandy Loam Soils
Authors: Upchurch R. P. , Corbin F. T. , Selman F. L.
Published: June 2019

Rates of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (diuron) up to 2.4 lb/A were applied as layby weed control treatments for cotton (Gossypium hirsutum L., var. Coker 100-A) in association with 0.0 or 1.0 lb/A of diuron as a preemergence treatment. Soybeans (Glycine max L. Merr., var. Lee) were grown as an alternate year rotational crop or as a rotational crop after cotton had been grown 3 years under diuron treatment. Similar rotational systems were evaluated in which corn (Zea mays L., var. Coker 71), tobacco (Nicotiana tabacum L., var. NC-95 or NC-2326), wheat (Triticum sativum Lam., var. Wakeland), cotton, and peanuts (Arachis hypogaea L., var. NC-2) served as the rotational crops in place of soybeans. In this mixed crop rotation, herbicidal treatments were 1.0 lb/A of diuron applied as a preemergence treatment plus 0.6 or 1.2 lb/A of diuron or 1.2 lb/A of 3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea (linuron) applied as a layby treatment. Two soil types near Rocky Mount, North Carolina were used. Herbicidal residues were determined by bioassay analyses in the fourth year of the experiment and by evaluating crops grown in the years when no herbicides were applied. Diuron residues were greater on Duplin soil than on Norfolk soil, but residues on Duplin soil were less phytotoxic to crops than those on Norfolk soil. The higher organic matter content of Duplin soil (1.2 vs 0.6%) is cited to account for both of these observations. When diuron was applied to Norfolk soil as a preemergence treatment at 1.0 lb/A plus 0.6 lb/A as a layby treatment, the residues frequently injured wheat, peanuts, and tobacco grown subsequently. Soybeans sometimes were injured by this treatment, but corn and cotton tolerated it even when the layby rate was increased to 1.2 lb/A. At equal layby rates, linuron produced residues of less consequence than diuron. At the higher application rates, greater residues occurred following 3 years of application than where application had been on an alternate year basis.
Herbicidal Control of Western Ironweed
Authors: McCarty M. K. , Scifres Charles J.
Published: June 2019

Applications of 2-methoxy-3,6-dichlorobenzoic acid (dicamba) and 2,4-dichlorophenoxyacetic acid (2,4-D) controlled top growth the year of treatment, but western ironweed (Vernonia baldwini Torr.) recovered in the following year. One-half lb/A or more of 4-amino-3,5,6-trichloropicolinic acid (picloram) effectively controlled top growth and destroyed roots and rhizomes. Treatment with 2 lb/A of picloram resulted in ironweed-free plots by the fourth season after treatment.
Effects of Foliarly Applied Desiccants on Selected Species under Tropical Environment
Authors: Bovey R. W.
Published: June 2019

Several contact and growth-regulator herbicides were evaluated as desiccants on greenhouse-grown cucumbers (Cucumis sativus L., var Ashly), sorghum (Sorghum bicolor L. Moench, var. Combine Kafir-60), mango (Mangifera indica L.), and field-grown guava (Psidium guajava L.). Pentachlorophenol (PCP) and 4,6-dinitro-o-sec-butylphenol (DNBP) consistently acted the fastest among compounds applied on several species. Herbicides such as 1,1'-dimethyl-4,4'-bipyridinium salt (paraquat) 6,7-dihydrodipyrido (1,2-a:2'c)pyrazidiinium salt (diquat), and the butyl esters of 2,4-dichlorophenoxyacetic acid plus 2,4,5-trichlorophenoxyacetic acid (2,4-D:2,4,5-T) were equally effective within 3 days after treatment of some species. Several other herbicides and herbicide mixtures were evaluated. Herbicide specificity and speed of desiccation varied with species. Adjuvants increased the phototoxicity of some herbicides.
A Laboratory Sprayer-Flamer
Authors: Burnside O. C.
Published: June 2019

A bench-mounted sprayer-flamer for research work is described. Constant rate spraying, logarithmic-dosage spraying, and flaming can be done at variable spray pressures and 10 speeds. The sprayer-flamer facilitates accurate and rapid application of material on plants and soil in pots and flats. The logarithmic-dosage sprayer gives a 16-fold variation in spray concentration over a 3-ft distance.
Vegetative Reproduction in Western Ironweed
Authors: Scifres C. J. , McCarty M. K.
Published: June 2019

The apex of western ironweed (Vernonia baldwini Torr.) vegetative bud shoots adheres to the tunica-corpus theory. Two layers of cells with the plane of wall formation anticlinal to the main axis (tunica) lie over a body of tissue with no pattern to wall formation (corpus). The bud shoot can be divided into the promeristem, the zone of elongation, and a zone of maturation on the basis of histology. It is suggested that the promeristem may be the seat for dormancy mechanisms in western ironweed and that future investigations be concentrated on this site. There was no evidence of a structural barrier to translocation separating the rhizome and bud shoot.
Effects of Selected Herbicides upon Growth of Soil Algae
Authors: Loeppky Carol , Tweedy B. G.
Published: June 2019

The effects of 2-chloro-4-ethylamino-6-isopropylamino-s-triazine (atrazine), N,N-dimethyl-2,2-diphenyl-acetamide (diphenamid), and N-(p-bromophenyl)-N'-methyl-N'-methoxyurea (metobromuron) upon autotrophic growth of four unicellular green algae were studied. Growth of Chlamydomonas reinhardi Dangeard was completely inhibited by 1 μg/ml metobromuron or 0.5 μg/ml atrazine and was stimulated by diphenamid. Five μg/ml metobromuron were toxic to Chlamydomonas eugametos Moewus, while atrazine and diphenamid had little effect on growth. Growth of Chlorella vulgaris Beijerinck was partially inhibited by atrazine and stimulated by diphenamid and metobromuron. At high concentrations, atrazine or metobromuron inhibited Chlorella pyrenoidosa Chick while growth was stimulated by diphenamid. The results obtained by treating with a combination of atrazine and metobromuron varied greatly with the organism. The effect of these three herbicides upon heterotrophic growth of Chlamydomonas reinhardi also was investigated. Both metobromuron and diphenamid were toxic in the dark. Atrazine had no effect upon heterotrophic growth.
The Etymology of Herbicide
Authors: Zimdahl Robert L.
Published: June 2019

The etymology of herbicide has been traced to a U. S. trademark originally registered by William J. Reade of the Reade Manufacturing Company.
Response of Sago Pondweed to Periodic Removal of Topgrowth
Authors: Ogg A. G. , Bruns V. F. , Kelley A. D.
Published: June 2019

A 2-year field study was conducted to determine the effects of periodic removal of topgrowth on tuber production and persistence of sago pondweed (Potamogeton pectinatus L.) in an irrigation canal. Plots were treated at 1, 2, and 4-week intervals throughout the irrigation season with aromatic solvent to kill the topgrowth. The tuber population was determined before the treatments began and at the end of each season. At the end of the first season, the number of tubers was reduced 78, 87, and 54% in the plots treated at 1, 2, and 4-week intervals, respectively. After two seasons, the number of tubers was reduced 91, 81, and 80%, respectively. All treatments controlled sago pondweed topgrowth effectively, but none eliminated the tubers completely.
Effect of Simulated Rainfall on Herbicide Performance
Authors: Bovey R. W. , Diaz-Colon J. D.
Published: June 2019

Studies were conducted to determine the effect of simulated rainfall on the phytotoxicity of several herbicides. Oil soluble herbicides 4,6-dinitro-o-sec-butylphenol (DNBP), pentachlorophenol (PCP), a 1:1 mixture of the butyl esters of 2,4-dichlorophenoxyacetic acid and 2,4,5-trichlorophenoxyacetic acid (2,4-D: 2,4,5-T), and a 2:2:1 mixture of the isooctyl esters of 2,4–13:2,4,5-T: 4-amino-3,5,6-trichloropicolinic acid (picloram) (hereinafter referred to as M-3140), usually were less affected by artificial rainfall than were water soluble 1,1'-dimethyl-4,4'-bipyridinium salt (paraquat), dimethylarsinic acid (cacodylic acid), and cis-2,3,5,5,5-pentachloro-4-ketopentenoic acid (hereinafter referred to as AP-20), on guava (Psidium guajava L.) and mango (Mangifera indica L.). Washing reduced the activity of some oil and water-soluble herbicides on sorghum (Sorghum bicolor (L.) Moench, var. Combine Kafir-60) and dioscorea (Dioscorea composita Hemsl). As herbicide rates were increased, washing reduced the phytotoxicity of paraquat and 2,4-D:2,4,5-T less on mango and guava. Artificial rainfall applied as a mist spray at different intervals had no effect on the phytotoxicity of paraquat; it reduced the activity of cacodylic acid and increased the effectiveness of AP-20 on mango.
Effects of Dichlobenil on Two Fishpond Environments
Authors: Cope Oliver B. , McCraren Joseph P. , Eller Lafayette
Published: June 2019

Pond studies were conducted at Tishomingo, Oklahoma with wettable powder 2,6-dichlorobenzonitrile (dichlobenil) and at Denver, Colorado with granular dichlobenil to measure chronic effects on fish and other effects on the ecosystem. Decline of the herbicide was rapid at Tishomingo, with only about 3% of the material remaining after 11 days, while at Denver the herbicide took 3 weeks to reach peak concentration in the water and was still measurable in the water after 189 days. Dichlobenil was present in bottom sediments after 312 days at Tishomingo and after 166 days at Denver. Weeds were controlled at both locations, but regrowth occurred after 3 months in ponds treated at 10 and 20 ppm dichlobenil. No immediate mortality was sustained by fish at either locality, but day-to-day mortality was serious at higher concentrations at Tishomingo. Reproduction apparently was affected by higher dichlobenil levels at Tishomingo. Growth of fish was fastest in ponds treated with highest rates of dichlobenil at Tishomingo, and slowest in the untreated ponds. Residues of dichlobenil developed in fish from all ponds, but faster at Tishomingo than at Denver, and larger in high-treatment ponds than in low-treatment ponds. Some pathology was seen in liver, kidney, and pancreas of Tishomingo fish.
Phytotoxicity and Movement of Amiben Derivatives in Soil
Authors: Linscott J. J. , Burnside O. C. , Lavy T. L.
Published: June 2019

In laboratory studies with 3-amino-2,5-dichlorobenzoic acid (amiben), adsorption of 14C-amiben was less than 14C-amiben methyl ester with all adsorbents tested. Adsorption of 14C-amiben was closely associated with soil organic matter. Also, considerable adsorption of 14C-amiben and 14C-methyl ester was observed on illite clay and on Sassafras loamy sand which contains clay minerals composed primarily of illite clay. Root uptake of amiben caused more injury than shoot uptake to greenhouse-grown corn (Zea mays L., var. Nebraska 202). The relatively insoluble butoxy ethyl ester of amiben was the most toxic amiben derivative to greenhouse-grown corn. Subirrigation moved the more soluble amiben derivatives to the soil surface where they had less effect on the root system. In field studies comparing four derivatives of amiben applied preemergence to corn in 1966, best weed control was from the ammonium salt of amiben at 2 and 4 lb/A and the methyl and butoxy ethyl ester at 4 lb/A; the amide was ineffective. The ammonium salt of amiben caused early stunting of corn but did not reduce yield. Selective weed control in soybeans [Glycine max (L.) Merr., var. Clark] was obtained in 1966 with the ammonium salt, 80% wettable powder, and monomethyl amine salt of amiben at 1 1/2 lb/A, and the methyl and butoxy ethyl ester at 6 lb/A. In 1967, the best amiben derivatives for weed control in soybeans were the amide and esters. Amiben derivatives more susceptible to leaching were less effective in controlling weeds in 1967 due to excessive rainfall after amiben applications.
Plant Growth Regulator Activity of Optical Isomers of DMPA
Authors: Holmsen T. W.
Published: June 2019

The herbicideO-(2,4-dichlorophenyl)O-methyl isopropylphosphoramidothioate (DMPA) contains an asymmetric tetracovalent phosphorus. Thed-isomer is much less active and thel-isomer more active thandl-DMPA in inhibiting seedling grass growth. Furthermore, low levels ofdl-DMPA stimulate root growth of seedling wheat (Triticum vulgareL., var. Soft winter).
Soybean Mitochondrial Response to Prometryne and Fluometuron
Authors: McDaniel J. L. , Frans R. E.
Published: June 2019

Experiments were conducted to determine the effect of 3-(m-trifluoromethylphenyl)-1,1-dimethylurea (fluometuron) and 2,4-bis(isopropylamino)-6-methylmercapto-s-triazine (prometryne) on oxygen consumption by mitochondria isolated from the hypocotyls of soybean (Glycine max L., var. Lee) seedlings. Prometryne caused a decrease in second state 3 oxidation of both malate and succinate, but the decrease was overcome by 2,4-dinitrophenol (hereinafter referred to as DNP), indicating a response similar to that of oligomycin. Fluometuron caused an increase in second state 4 oxidation of both malate and succinate and overcame the inhibition of oxidative phosphorylation caused by oligomycin, indicating an uncoupling response similar to DNP. Fluometuron was also shown to reverse the inhibition of oxidative phosphorylation caused by prometryne. Concentrations of prometryne causing the 50% inhibitory response were somewhat higher than those reported for s-triazines on other tissues, while those for fluometuron were well within the inhibitory range reported for other substituted ureas.
Metabolism of Trifluralin in Peanuts and Sweet Potatoes
Authors: Biswas P. K. , Hamilton Willie
Published: June 2019

Several investigations were undertaken to study the metabolism of alpha,alpha,alpha-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin) by intact peanut (Arachis hypogaea L.) and sweet potato (Ipomoea batatas L.) plants and crude extracts of these plants. Attempts also were made to determine the biological activity of three isolated degradative intermediates. Accumulated data indicated that trifluralin was degraded by both intact and crude extracts of these plants; the degradation pathway differing in each instance. In crude extracts of peanuts, the initial degradation product was an incomplete dealkylated derivative of the parent compound, alpha, alpha, alpha-trifluro-2,6-dinitro-N-propyl-p-toluidine. The initial degradation product formed in sweet potato crude extracts was a reduced derivative of trifluralin, N2,N2-di-n-propyl-3-nitro-5-trifluromethyl-o-phenylenediamine. All isolated degradation intermediates used in bioassay studies demonstrated root inhibition in cucumber (Cucumis sativus L.) at many of the concentration levels utilized. The greatest amount of root inhibition was observed in cucumber seeds germinated in alpha,alpha,alpha-trifluro-2,6-dinitro-N-(n-propyl)-p-toluidine.
Effects of 2,4,5-T During the Approach of Woody Plant Dormancy
Authors: Upchurch R. P. , Keaton J. A. , Coble H. D.
Published: June 2019

The shoots of naturally established specimens of turkey oak (Quercus laevis Walt.) and red maple (Acer rubrum L.) were treated under conditions of approaching dormancy. Aqueous sprays of 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) were applied as foliar treatments to the point of run-off at 2-week intervals beginning September 13 and continuing until three applications had been made for turkey oak and five had been made for red maple. Three experiments were conducted for turkey oak and two for red maple. Application rates were 2, 4, 8, and 16 lb of 2,4,5-T aehg of spray solution except that the 16-1b rate was deleted for turkey oak. Ester and amine derivatives were evaluated. Responses measured 9, 12, and 24 months after initiation of the experiments were percent control of original shoots, percent control of new shoots, shoot height, and number of live stems/plant. The average estimated control of original shoots of turkey oak and red maple increased from 42 to 54% as the application date was advanced from September 13 to October 11. The average height of the plants treated September 13 considering all evaluation dates was 3.4 ft compared to 2.6 ft for treatment made 4 weeks later. The results suggest two seasonal peaks in the response of some woody plants to foliar treatments of 2,4,5-T and that herbicidal effectiveness can be enhanced by application at the onset of senescence and dormancy.
Effect of Soil and Climate on Herbicide Dissipation
Authors: Burnside O. C. , Fenster C. R. , Wicks G. A. , Drew J. V.
Published: June 2019

The persistence of five herbicides in six soils across Nebraska can be ranked from greatest to least as follows: 5-bromo-3-isopropyl-6-methyluracil (isocil) at 5 and 25 1b/A, 2-chloro-4,6-bis-(isopropylamino)-s-triazine (propazine) at 3 and 9 1b/A, 2-chloro-4-ethylamino-6-isopropylamino-s-triazine (atrazine) at 3 and 9 1b/A, trichlorobenzyl chloride (hereinafter referred to as TCBC) at 7 and 49 1b/A, and 3-(3,4-dichlorophenyl)-1-methoxyl-1-methylurea (linuron) at 3 and 9 1b/A. Soil texture differences (sandy loam, very fine sandy loam, silt loam, and silty clay loam) had a greater influence on herbicide residue carryover than did climatic differences across Nebraska during 1962 to 1968. Soil carryover of herbicide residues was greater in coarse rather than fine-textured soils and in the drier regions of western than in eastern Nebraska. Leaching of herbicides into the soil profile was an avenue of herbicide dissipation.
Foliar and Root Absorption of Atrazine Applied Postemergence to Giant Foxtail
Authors: Thompson Lafayette , Slife F. W.
Published: June 2019

In growth chamber studies, high relative humidity and rewetting crystalline spray deposits of 2-chloro-4-ethylamino-6-isopropylamino-s-triazine (atrazine) increased absorption by and phytotoxicity to giant foxtail (Setaria faberii Herrm.), but phytotoxicity was restricted to expanded (unrolled) leaves unless some atrazine was absorbed by the roots. Though phytotoxicity was increased by simulated rainfall when root absorption was prevented, an appreciable number of the plants were killed only when atrazine residues were washed into the soil. In field studies, atrazine applied to a wet soil surface was as effective as the same rate of atrazine foliarly applied. In other field experiments, atrazine applied to giant foxtail on a wet soil and followed by simulated rainfall reduced stand and dry weight, but on a dry soil and not followed by simulated rainfall, atrazine reduced dry weight less and did not reduce stand. These results are due to root absorption of atrazine from wet soil. Spray additives increased phytotoxicity.
A Method for Spraying Individual Trees
Authors: Dowler Clyde C. , McCalmont J. R. , Byrom M. H.
Published: June 2019

Land availability and topography in Puerto Rico dictated the development of a method for evaluating herbicide foliage sprays on individual trees and small plots. A pneumatically operated aluminum mast with six telescoping sections, capable of extending from 12 to 50 ft and mounted on a swivel base, was fitted with two different spray delivery systems. A spray boom consisting of two 10-ft sections of 0.75-inch aluminum pipe and equipped with 12 diaphragm nozzles was mounted on the top of the telescoping mast. An alternate spray system was developed by attaching a modified Spraying Systems BoomJet unit to the top of the telescoping mast. To spray with the above systems, the mast is erected and guyed to a vertical position, the spray unit raised to the proper height, and the mast uniformly rotated through an arc of 240° during which the spray is delivered to opposite 180° portions of a circle. The spray coverage for both systems was similar for an area 20 ft in diam, but the droplet size and distribution was more uniform with the boom than with the Boomjet.
A Sprayer for Application of Small Amounts of Herbicides to Flats
Authors: Wilcox Merrill
Published: June 2019

A miniature sprayer designed for primary screening of herbicides is described. It uses a drift-free flat fan nozzle at low pressure. It has negligible dead volume and a minimum of wetted surface. Total cost was about $10.00 in 1967.
Influence of Oils on the Toxicity of Amitrole to Quackgrass
Authors: Aya F. O. , Ries S. K.
Published: June 2019

In field trials, 2 gpa of oil enhanced the herbicidal activity of 3-amino-1,2,4-triazole (amitrole) and a mixture of amitrole + ammonium thiocyanate (hereinafter referred to as amitrole-T) on quackgrass (Agropyron repens(L.) Beauv.). None of the oils consistently increased the toxicity of other foliarly-applied herbicides. A paraffinic mineral oil enhanced the activity of amitrole on quackgrass to a greater degree than NH4SCN. The inclusion of a paraffinic mineral oil enhanced both the amount and the rate of14C-amitrole and amitrole-T translocated from the treated leaf to the shoots and roots, this being more pronounced with amitrole (twelvefold) than with amitrole-T (twofold).
Uptake and Translocation of Diallate in Wheat, Barley, Flax, and Wild Oat
Authors: Nalewaja John D.
Published: June 2019

Uptake and translocation of 14C label from S-2,3-dichloroallyl N,N-diisopropylthiolcarbamate (diallate) by roots and coleoptiles of wild oat (Avena fatua L.), wheat (Triticum aestivum L., var. Selkirk), barley (Hordeum vulgare L., var. Traill), and flax (Linum usitatissimum L., var. Bolley) were compared. The pattern of 14C label uptake and movement was similar in wild oat, barley, and wheat. However, translocation of the 14C label to the roots of wild oat was less than for barley. Although differential uptake and translocation per se did not appear to account for the selectivity of diallate for wild oat, some differences in translocation may have beep the result of metabolic breakdown products.
Herbicidal Residues on Crested Wheatgrass
Authors: Klomp G. J. , Hull A. G.
Published: June 2019

The effects of residues of 16 herbicides used to control downy brome (Bromus tectorum L.) were studied in the greenhouse. Crested wheatgrass (Agropyron desertorum (Fisch. ex Link) Schult.) was planted in soils collected from field plots sprayed 1 to 4 years previously. At the rates used, some residues were lethal to crested wheatgrass seedlings, some caused severe malformation and/or herbage yield reduction, while others had no adverse effects.
Influence of Dichlobenil, Endothall, and Bromoxynil on Kinin Control of Proteolytic Activity
Authors: Penner Donald , Ashton Floyd M.
Published: June 2019

The herbicides 2,6-dichlorobenzonitrile (dichlobenil), 7-oxabicyclo-(2.2.1)heptane-2,3-dicarboxylic acid (endothall), and 3,5-dibromo-4-hydroxybenzonitrile (bromoxynil) were examined for their influence on the activity and synthesis of proteolytic enzyme(s) in the cotyledons of squash (Cucurbita maximaDuchesne) seedlings. None of these herbicides affected the activityper seof the isolated proteolytic enzyme(s). The presence of the herbicides in the culture solution during germination caused different effects on the development of the proteolytic activity in the cotyledons for each of the three herbicides. Dichlobenil reduced the development of the activity in both the excised cotyledons and the cotyledons of intact embryos. This inhibition was overcome in part by the addition of benzyladenine to the culture solution. The inhibition of hormone synthesis or export by the embryonic axis caused by dichlobenil could explain the observed results. Endothall inhibited the development of the proteolytic activity in the cotyledons of the intact embryo treatment but had little effect on the excised cotyledons. Benzyladenine did not reverse this inhibition. The effect of endothall resembled the inhibition caused by actinomycin D, possibly indicating that endothall interfered with ribonucleic acid metabolism. Bromoxynil inhibited the proteolytic enzyme(s) development in the cotyledons of intact embryos but not in the excised cotyledons. This inhibition was partly overcome by benzyladenine. These results suggest that bromoxynil not only interferes with the hormonal control mechanism but also proteinase synthesis.
The Tetrazolium Reaction as a Measure of the Action of Diquat in Elodea
Authors: Davies P. J. , Seaman D. E.
Published: June 2019

The production of red triphenyl formazan (hereinafter referred to as TPF) from colorless 2,3,5-triphenyl tetrazolium chloride (hereinafter referred to as TTC) by living cells was used as a vitality indicator for examining the effects of 6,7-dihydrodipyrido[1,2-a:2′,1′-c] pyrazidiinium salt (diquat) in elodea (Elodea canadensisMichx) shoots at varying light intensities. Diquat at 10 ppmw completely killed the elodea in 6 hr at 183 ft-c and at almost the same rate at 13,000 ft-c due to light saturation near the lower level. Over 24 hr were required for this effect in the dark. Between 29 and 183 ft-c, TPF production varied inversely with the light intensity. A comparison is made with the destruction of chlorophyll by diquat.
Effect of Paraquat and 2,4,5-T on the Uptake and Transport of Picloram in Woody Plants
Authors: Davis F. S. , Bovey R. W. , Merkle M. G.
Published: June 2019

We studied the uptake and transport of 4-amino-3,5,6-trichloropicolinic acid (picloram) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) alone and in combination and in the presence of 1,1′-dimethyl-4,4′-bipyridinium salt (paraquat) by honey mesquite (Prosopis juliflora(Swartz) DC. var.glandulosa(Torr.) Cockerell), huisache (Acacia farnesianaL. Willd., yaupon (Ilex vomitoriaAit.), and bean (Phaseolus vulgarisL.). Paraquat reduced transport of picloram by mesquite, huisache, and bean. Paraquat increased uptake of picloram by yaupon but did not affect transport. The uptake and transport of 2,4,5-T by mesquite decreased in the presence of picloram, but the uptake and transport of picloram increased in the presence of 2,4,5-T. Increasing ratios of 2,4,5-T:picloram up to 16:1 continued to increased uptake and transport of picloram; the inverse effect occurred for 2,4,5-T when picloram:2,4,5-T ratios were increased.
Response of Purple and Yellow Nutsedge to Dichlobenil
Authors: Hardcastle W. S. , Wilkinson R. E.
Published: June 2019

Purple nutsedge (Cyperus rotundus L.) and yellow nutsedge (Cyperus esculentus L.) tubers were stored at 5 C in soil treated at 0, 2, 3, 4, 6, 8, or 10 lb/A 2,6-dichlorobenzontrile (dichlobenil) for 2, 4, 6, 8, 10, or 12 weeks. Respiration of dormant tubers differed with species, unaffected by period of storage or dichlobenil concentration. Sprouting of untreated tubers decreased from 90% after 2 weeks storage to 43% after 12 weeks. Yellow nutsedge sprout production was uniform in time; purple nutsedge sprouting progressed to an 8-week high. Increased concentrations of dichlobenil progressively inhibited sprouting.
The Effect of Siduron Upon Barley Root Metabolism
Authors: Splittstoesser Walter E.
Published: June 2019

Barley (Hordeum vulgareL. var. Trail) root growth was inhibited at lower concentrations of 1-(2-methylcyclohexyl)-3-phenylurea (siduron) than was shoot growth. The influence of siduron upon root metabolism was assessed with excised roots grown in 0 or 5 ppm siduron. More glucose-U-14C and leucine-U-14C were degraded to CO2and less were incorporated into cell wall material and protein by roots grown in siduron. However, roots grown in siduron incorporated more adenine-8-14C into nucleic acids and degraded less adenine to CO2than roots grown in water. It was suggested that siduron disrupted the normal nucleic acid metabolism of barley roots which was necessary for protein and cell wall synthesis.
Soil Sterilization Properties of Monuron, Diuron, Simazine, and Isocil
Authors: Upchurch R. P. , Keaton J. A. , Selman F. L.
Published: June 2019

Under field conditions in North Carolina, yearly retreatment was required to provide reasonable soil sterility when an initial rate of 40 lb/A was used for each of the compounds 3-(p-chlorophenyl)-1,1-dimethylurea (monuron), 3-(3,4-dichlorophenyl)-1,1-dimethylurea (diuron), and 2-chloro-4,6-bis(ethylamino)-s-triazine (simazine). Lateral movement of these three herbicides was a major factor limiting their utility as soil sterilizers. Attempts to reduce lateral movement by using reduced herbicidal rates in combination with contact active additives were partially successful. The total soil sterilization performance index derived from sterility ratings and lateral movement ratings indicated that the combination of 5 lb/A of diuron and 2 lb/A of 1,1′-dimethyl-4,4′-bipyridinium salt (paraquat) could not be excelled by diuron or 5-bromo-3-isopropyl-6-methyluracil (isocil) regardless of the rate used. When used alone, the soil sterilization properties of diuron were equivalent to those for isocil, provided that the diuron rates were two and one-half times as great as those for isocil.
Germination of Medusahead in Response to Osmotic Stress
Authors: Young James A. , Evans Raymond A. , Gifford Richard O. , Eckert Richard E.
Published: June 2019

Requirements for germination and rate of juvenile root and shoot elongation of 23 medusahead (Taeniatherum asperum (Sim.) Nevski) selections were investigated in relation to osmotic stress. These were compared with the germination and elongation characteristics of other grasses. Aqueous solutions of different osmotic pressures were obtained by dissolving polyethylene glycol in water. Successive 4-bar increases in osmotic pressure markedly reduced medusahead germination until germination terminated at 16 bars. Other grass species exhibited higher germination than medusahead under osmotic stress. Medusahead juvenile root and shoot elongation under low and moderate osmotic pressure exceeded all other species tested.
Economic Comparison of Mechanical and Chemical Weed Control
Authors: Armstrong David L. , Leasure J. K. , Corbin Mitchell R.
Published: June 2019

The problem in determining the economic feasibility of mechanical, chemical, and combination weed control methods in corn (Zea mays L.) is a complex decision involving many factors. The effects of cost, yield, timeliness, and alternative uses of labor are the factors considered in comparing various methods of weed control in this study. Costs of weed control operations range from $2.84/A for two cultivations to $10.45/A for the most intensive, mechanical-chemical operation studied. Most common weed control methods have costs of approximately $3 to $4/A. Yields range from 83 bu/A for two cultivations to 96 bu/A with the highest cost chemical-mechanical weed control methods. All yields used in this study are supported by agronomic studies and are indexed on the basis of 100 bu/A for weed-free conditions. The consideration of both yields and costs does affect the selection of a weed control method. Considering only these two factors, mechanical methods have a slight advantage over chemical weed control methods. Penalizing mechanical methods because of delay or timeliness characteristics gives chemical methods an advantage by as much as $3.00/A. Alternative uses of labor, even though a common argument in selecting chemical or mechanical methods, is a very small item and has only moderate effects on the changes in net income.
Fluorometric Analysis for Evaluation of Soil Incorporation
Authors: Williford J. R. , Wooten O. B. , Barrentine W. L.
Published: June 2019

A fast and efficient method of evaluating soil incorporators consists of incorporating a fluorescent dye into the soil, taking soil samples, removing the dye by a solvent, and determining the dye concentration. Pontacyl Brilliant Pink B was the best dye for incorporation studies and a fluorometer was the analytical instrument.
Simazine Distribution and Degradation in Red Pine Seedlings
Authors: Dhillon P. S. , Byrnes W. R. , Merritt C.
Published: June 2019

Distribution and degradation of 2-chloro-4,6-bis(ethylamino)-s-triazine (simazine) at 5, 10, 15, and 20 ppmw in red pine (Pinus resinosa Ait.) seedlings were investigated using 14C-ring-labeled simazine dispersed in agar medium. Simazine readily entered red pine roots and moved rapidly into stem and needles. Accumulation was greatest in roots, next in stems, and least in needles. Significant differences in simazine uptake by roots were observed among concentrations between 5 and 20 ppmw in the incubation medium. Radiochromatographic scans revealed that a small amount of simazine was degraded to three unknown compounds by both fresh and boiled homogenates from whole plants, needles, stems, and roots. There were no observable differences in the amount of simazine degraded by homogenates of each separate plant part.
A Shielded, Tractor-Mounted Sprayer for Research Plots
Authors: Burnside O. C.
Published: June 2019

A shielded, tractor-mounted sprayer for research plots is described. Advantages of this sprayer for research plots are reduced spray drift, rapid and thorough cleaning between herbicide treatments, adequate mixing of herbicide suspensions, rapid and accurate herbicide application, and facilitating plots large enough to take yield data with a combine.
Germination, Growth, and Ecology of Sicklepod
Authors: Creel J. M. , Hoveland C. S. , Buchanan G. A.
Published: June 2019

Germination, growth, and potential phytotoxicity of sicklepod (Cassia obtusifolia L.) were studied. Seed germination occurred in the temperature range from 18 to 36 C, but rapid seedling growth occurred only between 30 and 36 C. Seed dormancy caused by a waxy coat resulted in only 15% germination in soil over a 12-month period. A 1:15 (g/ml) water extract of sicklepod tops inhibited germination of cotton (Gossypium hirsutum L.) and oat (Avena sativa L.) seed. Incorporation of sicklepod residues in soil reduced germination of cotton seed but increased persistence of sericea (Lespedeza cuneata (Dumont) G. Don.) and crimson clover (Trifolium incarnatum L.) because damping-off was almost eliminated. There was evidence in nutrient cultures that sicklepod released a phytotoxic residue from its roots, reducing growth of cotton but having no effect on soybeans (Glycine max (L.) Merr.). Sicklepod grew well in soils ranging from pH 3.2 to 7.9. Sicklepod response to N, P, and K levels was similar to cotton and higher than that of soybeans.
Chromatographic Determination of Metobromuron and Metabolites in Soil
Authors: Katz Stanley E. , Fassbender Carol A.
Published: June 2019

Chromatographic procedures were developed for use in the laboratory studies of the breakdown of N-(p-bromophenyl)-N′-methoxy-N-methoxyurea (metobromuron) in soils. Both thin-layer and gas chromatographic procedures were developed to determine the known and/or suspected metabolic products occurring from the microbiological transformations in soil. Extraction of 3 soils, after 5 days of equilibration, yielded all the metabolites. Neither the gas chromatographic or thin-layer procedures were affected by soil extractives.
The Effect of Different Canada Thistle Ecotypes on Amitrole Activity
Authors: Burt G. W. , Muzik T. J.
Published: June 2019

Susceptible and resistant ecotypes of Canada thistle (Cirsium arvense L.) were grafted in various combinations of stock and scion to determine if the activity of 3-amino-l,2,4-triazole (amitole) was altered by passage through the plant tissue. It appeared that the differential susceptibilities of ecotypes of Canada thistle were not caused by a change in the activity of amitrole.
Residual Effects of EPTC and Trifluralin Incorporated with Different Implements
Authors: Robison L. R. , Fenster C. R.
Published: June 2019

Applications of a,a,a-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin) at 1/2 and 1 lb/A and ethyl N,N-dipropylthiocarbamate (EPTC) at 1 1\2 and 3 lb/A were incorporated preplant with five different tillage implements to determine the influence of incorporation on weed control effectiveness in safflower (Carthamus tinctorius L.). Weed yields were lowest in plots incorporated with the tandem disc and rotary incorporator. Oats (Avena sativa L.) were overseeded 1 year later on the entire safflower plot area. Stand loss occurred on plots receiving the high rate of both herbicides and incorporated with the disc or rotary incorporator.
The Translocation of Two Organic Arsenicals in Purple Nutsedge
Authors: Duble R. L. , Holt E. C. , McBee G. G.
Published: June 2019

The translocation of disodium methanearsonate (DSMA) and amine methanearsonate (hereinafter referred to as AMA) in purple nutsedge (Cyperus rotundus L.) was studied following foliar applications. Tracer techniques with DSMA-14C and chemical analyses for elemental arsenic (hereinafter referred to as As) suggested apoplastic and symplastic movement of both arsenicals. Chromatographic studies of extracts from DSMA-14C-treated plants indicated that the compound was not readily broken down. The carbon-arsenic bond appeared to remain largely intact, although some 14C activity was found in respiratory CO2 several days after treatment. A comparison between the Rf value of the radioactive plant extract to that of standard DSMA-14C suggested that a plant extract-DSMA complex may have been formed. Over 85% of the material applied to the plant remained in the treated shoots. DSMA moved in both acropetal and basipetal directions, and such movement within a single leaf was not influenced by relative leaf age. The arsenicals were not redistributed in the shoot or in the tuber system, but As was accumulated in terminal tubers following repeated applications.
Mist Blowing Versus Other Methods of Foliar Spraying for Hardwood Control
Authors: Peevy Fred A. , Brady Homer A.
Published: June 2019

A tractor-mounted mist blower was as effective as a high-volume ground sprayer or an airplane sprayer for applying herbicides to control hardwoods in two tests in central Louisiana. Two lb/A of butoxyethanol ester of 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) were slightly better than one, and May treatments were more effective than August treatments.
Reproductive Characteristics of Honeyvine Milkweed
Authors: Robinson E. L.
Published: June 2019

The prolificacy of honeyvine milkweed [Ampelamus albidus (Nutt.) Britt.] was investigated. Mature seeds stored at 0, 10, and 24 C and germinated at 32 C demonstrated high viability from harvest to 1 year old. Immature seeds were slightly less viable but followed the same trends in germination. Studies with rhizomes excavated at four different times throughout the year showed that segments 1 inch long with at least one live bud were capable of generating regrowth. These reproductive characteristics with the inherent tenacity of honeyvine milkweed indicate a potentially serious weed problem in many agricultural regions of the United States.
Control of Quackgrass with Pyriclor
Authors: Buchholtz K. P.
Published: June 2019

Quackgrass (Agropyron repens (L.) Beauv.) was controlled with applications 1 to 8 months prior to plowing and planting of from 1 to 4 lb/A 2,3,5-trichloro-4-pyridinol (pyriclor). Corn (Zea mays L., hybrid W530) planted on pyriclor-treated plots grew normally and yielded as well as on plots given the standard preplow treatment of 2 lb/A of 2-chloro-4-ethylamino-6-isopropylamino-5-triazine (atrazine). Oats (Avena sativa L., var. Portage) was injured by soil residues of pyriclor from 2-lb/A applications made 20 months previously. Alfalfa (Medicago sativa L., var. Vernal) was somewhat more tolerant of pyriclor than was oats.
Smooth Bromegrass Response to Herbicides as Affected by Time of Application in Relation to Nitrogen Fertilization
Authors: McCarty M. K. , Scifres C. J.
Published: June 2019

Smooth bromegrass (Bromus inermis Leyss.) treated in the fall tended to be more damaged than that treated in the spring, regardless of herbicide. Nitrogen fertilizer reduced the loss in yield resulting from herbicides but was least effective with 1 lb/A of 4-amino-3,4,6-trichloropicolinic acid (picloram). Laboratory studies showed that roots of smooth bromegrass were the primary site of picloram uptake. Root uptake explained the severe damage in curred from applications of picloram made in the fall. The order of increasing phytotoxicity of herbicides to smooth bromegrass studied in these experiments was 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) and 2,4-dichlorophenoxyacetic acid (2,4-D)<2-methoxy-3,6-dichlorobenzoic acid (dicamba) < picloram.
Interactions of Four Herbicides with Rhizoctonia solani on Seedling Cotton
Authors: Chandler James M. , Santelmann P. W.
Published: June 2019

Growth chamber and field studies were conducted to investigate the possibility of an interaction between the herbicides 4-(methylsulfonyl)-2,6-dinitro-N,N-dipropylaniline (nitralin), a,a,a-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin), 3- (m-tri-fluromethylphenyl)-1,1-dimethylurea (fluometuron), and 2,4-bis(isopropylamino)-6-methylmercapto-s-triazine (prometryne), and the seedling disease organism Rhizoctonia solani Kuehn in cotton (Gossypium hirsutum L.). When high levels of trifluralin or prometryne were used in the growth chamber, an interaction with the pathogen that was injurious to the cotton occurred. Prometryne and fluometuron produced an antagonistic effect on R. solani.

Under field conditions, R. solani usually caused cotton injury. Interactions injurious to the cotton occurred between trifluralin and a low level of R. solani and between nitralin and a high level R. solani infestation. No interactions occurred with fluometuron or prometryne. In all instances, the effect occurred only when the herbicides were being used at high rates.
Factors Affecting Performance of Preemergence Herbicides
Authors: Jordan L. S. , Lyons J. M. , Isom W. H. , Day B. E.
Published: June 2019

Spray and granular forms of isopropyl N-(3-chlorophenyl)-carbamate (CIPC, ethyl N,N-dipropylthiocarbamate (EPTC), a,a,a-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin) and 2,4-bis(isopropylamino) -6-methylmercapto-s-triazine (prometryne) were incorporated preemergence to barnyardgrass Echinochloa crusgalli (1.) Beauv.) and broadleaf weeds with a rotary tiller, wheel hoe, rotary spike, or row wheel into pre-irrigated or dry soil at three locations. The locations varied in type of soil, climatic conditions, and the species of broadleaf weeds. Rotary tiller incorporation generally resulted in best weed control with both spray and granular forms under all conditions. Herbicides usually performed best in pre-irrigated soil. Sprays and granules were equal in performance at coastal and intermediate locations; granules were more effective in the desert location. Herbicidal effectiveness was influenced by method of incorporation, form of treatment, soil moisture, environmental location, and weed type.
Chemical Control of Reed Canarygrass on Irrigation Canals
Authors: Hodgson J. M.
Published: June 2019

From 1962 to 1967, we evaluated herbicides for control of natural infestations of reed canarygrass (Phalaris arundinacea L.) on canal banks of the Huntley, Montana irrigation project. Two,2-dichloropropionic acid (dalapon) and 3-amino-1,2,4-triazole ammonium thiocyanate (hereinafter referred to as amitrole-T) controlled reed canarygrass. These herbicides were compared with a number of others. Spring foliage treatments with a combination of amitrole-T at 2 1b/A and dalapon or trichloroacetic acid (TCA) at 5 or 10 1b/A were more effective than amitrole-T at 4 1b/A. Amitrole-T was more tolerant to fine grasses such as Kentucky bluegrass (Poa pratensis L.) or redtop (Agrostis alba L.) than dalapon and in some situations it was more desirable than dalapon. Dalapon and TCA were more effective as late fall or early winter treatments to control reed canarygrass during the following growing season. Rates of 20 or 40 1b/A controlled the grass for one season even at the water's edge where it is usually more persistent. At 5 to 10 1b/A, 2,3,5-trichloro-4-pyridinol (pyriclor) controlled reed canarygrass, and it also was effective at 2 1b/A with 2 1b/A of amitrole-T.
Influence of Herbicides on Japanese Holly and Hand Labor for Weed Control
Authors: Bingham S. W.
Published: June 2019

Fall treatments with 2-chloro-4,6-bis(ethylamino)-s-triazine (simazine) as opposed to cultivation during the growing season reduced hand labor requirements more than 70% for weed control in Japanese holly (Ilex crenata Thumb. Rotundifolia Hort.). The response of Japanese holly to simazine varied from superior growth and quality to severe injury and death. Simazine plus 3-amino-1,2,4-triazole (amitrole) resulted in better control of small weeds than simazine alone in late winter or early spring. Dimethyl 2,3,5,6-tetrachloroterephthalate (DCPA), N,N-dimethyl-2,2-diphenylacetamide (diphenamid), and 2,6-dichlobenzonitrile (dichlobenil) reduced labor requirements for control of annual weeds without any visual response on the Japanese holly. In certain instances, rotations of herbicides were effective for broad spectrum weed control.
Inhibition of Degradation of Monuron in Cotton Leaf Tissue by Carbamate Insecticides
Authors: Swanson C. R. , Swanson H. R.
Published: June 2019

Simultaneous treatment with certain carbamate insecticides inhibited degradation of 3-(p-chlorophenyl)-1,1-dimethyrurea (monuron) in cotton (Gossypium hirsutumL.) leaf discs. Monuron degradation was strongly inhibited by 1-naphthyl methylcarbamate (carbaryl) and 4-benzothiophene-N-methylcarbamate, but 2,3-dihydro-2,2-dimethyl-7-benzofuranyl methylcarbamate was ineffective. Effective carbamates did not prevent the metabolism of monuron to 1-(p-chlorophenyl)-3-methylurea (hereinafter referred to as monomethylmonuron), but they inhibited subsequent degradation of monomethylmonuron.
Analysis of Emulsified Xylene in Water
Authors: Frank Peter A.
Published: June 2019

Emulsions of aromatic solvent or dimethylbenzene (xylene) are used to control submersed aquatic weeds in irrigation systems. A procedure was developed for analyzing the concentrations of xylene in irrigation water. Samples of xylene emulsions were collected in glass bottles containing tetrachloromethane (CCl4). Xylene and emulsifier were partitioned into the CCl4. After addition of sodium chloride (NaCl) to remove the emulsifier from the CCl4, aliquots of the CCl4 were analyzed for xylene content by gas chromatography. Extraction of xylene from the water was complete and quantities of xylene as small as 10 ng were readily detected.
Competitive Effects of Wild Oat in Flax
Authors: Bell Allyn R. , Nalewaja John D.
Published: June 2019

Wild oat (Avena fatua L.) competition severely reduced flaxseed (Linum usitatissimum L.) yield. Averaged over two locations and two fertility levels, 80 wild oat plants/sq yd reduced the yield 9.4 bu/A (60.1%) in 1964 and 160 wild oat plants/sq yd reduced the yield 21.5 bu/A (82.1%) in 1965. At Fargo, 160 wild oat plants/sq yd reduced flaxseed yield 16.1 bu/A (86.1%) in 1966. Flaxseed yield components, including bolls/sq ft, seeds/boll, plants/sq ft, and weight/1000 flaxseed were determined. Although all components were reduced by wild oat competition, a reduction in the number of branches and flax bolls/sq ft accounted for 90.7% of the yield loss. A reduction in weight/1000 seed and the number of flax plants/sq ft contributed 7.0% and 4.6% to the yield loss, respectively. Competition from wild oat also reduced flaxseed quality. The percent oil was reduced in all 3 years of the experiment. Iodine number of the oil was reduced, primarily because of an increase in oleic acid and a decrease in linolenic acid.
Effect of Duration of Wild Oat Competition in Flax
Authors: Bell Allyn R. , Nalewaja John D.
Published: June 2019

Wild oat (Avena fatua L.) was removed at several stages of growth from flax (Linam usitatissimum L.) plots in 1964, 1965, and 1966. The flaxseed yield was reduced as the period of competition increased during each year. In 1965, competition from wild oat until the 4 to 5-leaf stage reduced the flaxseed yield 15.1% while competition until maturity reduced the yield 74.9%. The number of bolls/sq ft also was reduced as the period of competition increased; but the number of seed/boll, plants/sq ft, and the weight/1000 seed were not affected consistently by wild oat competition. Both the percent oil of flaxseed and the iodine number of the oil were reduced by wild oat competition, but not until the wild oat was in the heading stage and the flax was in the boll stage.