bluuebunny/crossref_metadata_2025 huggingface dataset:
Tall Waterhemp Competition in Grain Sorghum
Authors: Feltner K. C. , Hurst H. R. , Anderson L. E.
Published: June 2019

Grain sorghum (Sorghum vulgare Pers.) was grown in combination with varying densities and durations of tall waterhemp (Acnida altissima Riddell) during 1964 and 1965 at Manhattan, Kansas. As waterhemp density and duration increased, sorghum fodder and grain yields were reduced. Yields of both species and competitive influence of waterhemp were highest during the year of high rainfall and supplemental N fertility. The net competitive influence of waterhemp on sorghum grain was accounted for principally by reduced seed size. Competition for soil moisture in 1965 was greatest when weeds remained full-season, and was most pronounced early in the season at soil depths below 20 inches.
A Survey of the Chemical Composition of Potamogeton and Myriophyllum in New Jersey
Authors: Riemer D. N. , Toth S. J.
Published: June 2019

Several species of Potamogeton and Myriophyllum from New Jersey were collected and analyzed for 11 elements. Wide variations were observed in the inorganic composition of the plants, both within species and among species. In some instances, there appeared to be a relationship between the content of a specific element in a plant sample and the content of that element in the water in which the plants were growing. The nitrogen content of the plants was sufficiently high so that no extra nitrogen would be required to prepare composts from them.
Importance of Root, Shoot, and Seed Exposure on the Herbicidal Activity of EPTC
Authors: Gray Reed A. , Weierich Andre J.
Published: June 2019

A charcoal barrier method was devised to prevent the movement of S-ethyl dipropylthiocarbamate (EPTC) in the soil in order to expose certain parts of the plant without exposing the rest of the plant. Exposing the roots of barley (Hordeum vulgare L., var. Blue Mariot), oats (Avena sativa L., var. California Red), barnyardgrass (Echinochloa crusgalli L. Beauv.), annual ryegrass (Lolium multiflorum Lam.), wheat (Triticum vulgare L.), rice (Oryza sativa L., var. Belle Patna), cotton (Gossypium peruvianum Cav.), and yellow nutgrass (Cyperus esculentus L.) caused more injury than shoot exposure, while shoot exposure caused slightly more injury than root exposure to Johnsongrass (Sorghum halepense Pers.), sorghum (Sorghum vulgare Pers., hybrid Amak R-10), and peas (Pisum sativum L.). Seed exposure caused severe injury in some plant species but not others. The results obtained by this method disagree with published reports which claimed that only shoot exposure to EPTC led to injury. In numerous experiments with barley seeds accurately planted in a vertical position in a ½-inch layer of charcoal between two 1-inch layers of soil, root exposure always injured the plants more than shoot exposure. Exposing all parts (seeds, roots, and shoots) to EPTC caused the most injury to barley followed by exposing only the seeds, a combination of roots and shoots, roots, and shoots in decreasing order of injury symptoms. Similar results were obtained with oats when the depth of the treated soil above or below the seed was 1 inch, but increasing this depth to 1.5 inches or more resulted in more injury by shoot exposure than root exposure. The importance of root exposure was confirmed using another method of testing in which only the roots were exposed to the herbicide in nutrient solutions. Concentrations as low as 1 ppm of EPTC applied to the roots in nutrient solutions inhibited shoot growth of oats, barley, sorghum, and corn, while the growth of the roots was enhanced in some cases.
Control of Green Rabbitbrush and Big Sagebrush with 2,4-D and Picloram
Authors: Tueller Paul T. , Evans Raymond A.
Published: June 2019

A mixed stand of green rabbitbrush (Chrysothamnus viscidiflorus (Hook.) Nutt. var. puberulus Jepson) and big sagebrush (Artemisia tridentata Nutt.) was sprayed at different dates for 3 years with potassium salt of 4-amino-3,5,6-trichloropicolinic acid (picloram) at ¼, ½, and 1 1b/A, propylene glycol butyl ether esters of 2,4-dichlorophenoxyacetic acid (2,4-D) at 1, 2, and 3 1b/A, and a mixture of triisopropanolamine salts of picloram plus 2,4-D at ¼ plus 1 and ½ plus 2 1b/A. Picloram at ½ and 1 1b/A controlled rabbitbrush but not sagebrush. Poor rabbitbrush control and fair to good sagebrush control resulted from 2,4-D. The mixture of picloram and 2,4-D controlled rabbitbrush well but only partially controlled sagebrush. Forage release from brush control was negligible the first 2 years after spraying. During the third and subsequent years, production of crested wheatgrass (Agropyron desertorum (Fisch.) Schult.) was greatly increased.
Distribution of Miserotoxin in Varieties of Astragalus miser Dougl. ex Hook.
Authors: Williams M. Coburn , Norris Frank A.
Published: June 2019

A method was developed for quantitative determination of miserotoxin, a poison in timber milkvetch (Astragalus miser Dougl. ex Hook.). The presence and concentration of miserotoxin was determined in eight varieties of timber milkvetch. The seasonal variation in the concentration of the poison was followed in variety oblongifolius (Rydb.) Cron. Miserotoxin occurred primarily in the leaves with smaller amounts in the roots, flowers, and seeds. The poison level in leaves and stems decreased rapidly after seed dispersal. Miserotoxin was found in varieties oblongifolius (Rydb.) Cron., serotinus (Gray) Barneby, and hylophilus (Rydb.) Barneby, but was not found in varieties miser Dougl. ex Hook., tenuifolius (Nutt.) Barneby, crispatus (Jones) Cron., praeteritus Barneby, and decumbens (Nutt.) Cron. The three varieties containing miserotoxin were poisonous to 1-week-old chicks (Gallus domesticus, Arbor Acre 50 × Vantress hybrids); the other five varieties were not poisonous.
Effects of Chlorpropham Vapors on Dodder Seedlings
Authors: Slater C. H. , Dawson J. H. , Furtick W. R. , Appleby A. P.
Published: June 2019

Dodder (Cuscuta spp.) seedlings were killed when exposed to isopropyl m-chlorocarbanilate (chlorpropham) vapors in an enclosed system or in the open atmosphere in the greenhouse or field. No seedlings wrapped on the host when they were exposed for 16 hr or more in an enclosed system. Alfalfa (Medicago sativa L.) foliage restricted air movement near the treated soil and favored accumulation of vapors that killed emerged and emerging seedlings.
Soil Moisture and Effectiveness of Preemergence Herbicides
Authors: Stickler R. L. , Knake E. L. , Hinesly T. D.
Published: June 2019

The relation between soil moisture and the effectiveness of preemergence herbicides for control of giant foxtail (Setaria faberii Herrm.) was studied under greenhouse conditions using surface soil from Drummer silty clay loam with 25, 31, and 37% moisture. Herbicides used were 2-chloro-4-ethylamino-6-isopropylamino-s-triazine (atrazine), ethyl N,N-dipropylthiocarbamate (EPTC), 3-amino-2,5-dichlorobenzoic acid (amiben), α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin), 2-chloro-N-isopropylacetanilide (propachlor), and 2-chloro-N-(methoxymethyl)-2',6'-diethyl-acetanilide (hereinafter referred to as CP 50144). The effectiveness of atrazine and EPTC was increased when soil moisture was raised from 25 to 31%, but no further increase was obtained at 37% moisture. Response to amiben increased linearly and response to trifluralin decreased linearly with increasing moisture. Increasing moisture within this range had little effect on propachlor or CP 50144.
Organic Matter-Amiben Interaction on Nodulation and Growth of Soybeans
Authors: Olumbe Johnes W. K. , Veatch Collins
Published: June 2019

Wheat (Triticum aestivum, subspecies vulgare L.) straw, sawdust, peat, and cellulose pulp were mixed with Westmoreland silt loam in a 2 to 1 ratio (soil to organic matter) in a greenhouse study, on the influence of organic matter-interaction with 3-amino-2,5-dichlorobenzoic acid (amiben) on nodulation and growth of soybeans (Glycine max L., var. Clark). The dry weights of shoots and roots, harvested 1 week after flower initiation in the control, decreased with increasing rates of amiben in the unamended soil and in soil in which cellulose pulp and peat were mixed.
Amiben Metabolism and Selectivity
Authors: Stoller E. W. , Wax L. M.
Published: June 2019

Absorption and metabolism of 14C-3-amino-2,5-dichlorobenzoic acid (amiben) by six plant species were investigated for correlation with species sensitivity. Plant sensitivity was determined from amiben concentrations required to give 50% reduction of radicle extension of germinating seedlings and shoot dry weight of 10-day-old plants (I50). The I50 values showed that soybean (Glycine max (L.) Merr., squash (Cucurbita pepo L.), and ivyleaf morningglory (Ipomoea hederacea (L.) Jacq.) were tolerant, cucumber (Cucumis sativus L.) was intermediate and giant foxtail (Setaria faberii Herrm.) and velvetleaf (Abutilon theophrasti Medic.) were susceptible. Neither the amount of amiben absorbed, the transport to shoots, the concentration of radioactivity soluble in methanol, nor the distribution of radioactivity among amiben, N-(3-carboxy-2,5-dichlorophenyl)-glucosylamine (hereinafter referred to as N-glucosyl amiben), and an unidentified amiben conjugate (amiben-X) was associated with species sensitivity in 11-day-old plants. In seedling tissues, neither the concentration of methanol-soluble nor methanol-insoluble radioactivity correlated with sensitivity. Highly significant correlations between the log percentage composition of amiben, amiben-X, and N-glucosyl amiben in the methanol-soluble fraction of seedlings and log I50 for radical elongation were obtained; the correlations were negative for amiben and amiben-X but positive for N-glucosyl amiben.
The Metabolism of Vernolate-14C in Soybean Seedlings
Authors: Bourke John B. , Fang S. C.
Published: June 2019

The metabolism of S-propyl-1-14C dipropylthiocarbamate (vernolate) was studied in soybean (Glycine max (L.) Merr., var. Lee) seedlings. The degradation of vernlate-14C to 14CO2 was dependent on the age of seedlings. Pretreatment with non-labeled vernolate resulted in a reduction of catabolic oxidation of vernolate-14C to 14CO2, a reduction of cellular incorporation, and a corresponding increase in ethanol soluble metabolites. Paper chromatographic separation of ethanol extracts revealed the presence of two major metabolites and two minor metabolites. The relative abundance of these metabolites was dependent on the age of seedlings and the time of exposure. Results of the time course study suggested the conversion of metabolite 3 to metabolite 4.
Uptake and Translocation of Diquat in Elodea
Authors: Davies P. J. , Seaman D. E.
Published: June 2019

Uptake and translocation of 6,7-dihydrodipyrido[1,2-a:2′, 1′-c]pyrazidiinium salt (diquat) in elodea (Elodea canadensis Michx) was investigated by autoradiography and counting of plants treated with diquat-14C. Uptake initially was very rapid followed by a slower accumulation of diquat. Part of this uptake was reversible in water and rapidly reached a saturation value while the slower uptake was nonreversible. This reversibility of uptake appears to indicate an initial passive adsorption probably followed by accumulation. Slight basipetal and acropetal movement of diquat was demonstrated with accumulation in the nodes and axillary buds. Movement was unaffected by light versus dark treatments. Diquat injured treated and adjacent untreated shoots of elodea to almost the same extent. This transfer occurred whether or not the treated and untreated shoots were in contact.
Physiological Effects of Fluometuron on Some Unicellular Algae
Authors: Sikka H. C. , Pramer David
Published: June 2019

Unicellular green algae were used as test organisms in experiments designed to provide an insight into the mode of action of 3-(m-trifluoromethylphenyl)-1,1-dimethylurea (fluometuron). Fluometuron suppressed the autotrophic growth ofChorella pyrenoidosaChick (hereafter referred to asC. pyrenoidosa) andEuglena gracilisKlebs-strain ‘Z’ (hereafter referred to asEuglena) and the extent of inhibition was a function of herbicidal concentration.Euglenawas less sensitive thanC. pyrenoidosa. Treated cells contained less protein and chlorophyll than untreated cells, but the inhibitory effect of the herbicide on the algal growth was overcome when the organisms were grown heterotrophically. Fluometuron did not adversely influence respiration or the light-independent reactions that lead to the formation of chlorophyll or chloroplast precursors. It did interfere with the light-dependent or the greening process of chlorophyll synthesis and with photosynthetic oxygen evolution. Fluometuron appears to be selectively toxic to one or more light-mediated biochemical reactions required for the formation and function of photosynthetic pigments and organelles.
Tolerance of Sugarcane Varieties to Herbicides
Authors: Millhollon Rex W. , Matherne Rouby J.
Published: June 2019

Five herbicides were applied postemergence to three Louisiana sugarcane (Saccharum officinarum L.) varieties. Nine or 12 lb/A of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (diuron) severely injured varieties C.P. 44-101 and C.P. 52-68, but variety N.Co. 310 was not affected. Conversely, N.Co. 310 was injured more by 2,2-dichloropropionic acid (dalapon) than the other varieties. Trichloroacetic acid (TCA) + 2,4-dichlorophenoxyacetic acid (2,4-D) at 10.6 plus 3 lb/A, reduced the yield of variety N.Co. 310 in one of 2 years only. This treatment had no adverse effect on yields of the other two varieties. All varieties appeared tolerant to 2,3,-6-trichlorophenylacetic acid (fenac) applied at 4 to 12 lb/A. Diuron injured a sensitive variety both when the foliage was sprayed and when only the ground at the base of the cane was sprayed. Plants treated in May were injured more than those treated 30 days earlier.
Response of Highbush Blueberries to Long-term use of Diuron and Simazine
Authors: Welker William V. , Brogdon Jennie L.
Published: June 2019

Highbush blueberries [Vaccinium australe (Small), var. Colville] grown on a Leon sand at Chatsworth, New Jersey were treated with 3-(3,4-dichlorophenyl)-1,1-dimethylurea (diuron) and 2-chloro-4,6-bis(ethylamino)-s-triazine (simazine) each spring or each spring and fall from 1960 through 1966. The weed control obtained with diuron generally improved with continued use. At rates of simazine sufficient to achieve satisfactory control, the degree of weed control increased for the first 3 years and decreased the last 3 years. Diuron and simazine at rates sufficient to provide satisfactory weed control did not reduce the productivity of the blueberry plant. Palatability evaluations of off-flavor and sweetness of frozen blueberries, and objective measurements of pH and soluble solids, indicated that the diuron and simazine treatments did not affect any of these quality factors.
Metabolism of Siduron by Barley and Crabgrass
Authors: Splittstoesser Walter E. , Hopen Herbert J.
Published: June 2019

At rates as high as 40 lb/A, 1-(2-methylcyclohexyl)-3-phenylurea (siduron) did not reduce the growth of crabgrass (Digitaria spp.) seedlings although it was highly toxic to germinating seeds. Siduron placed at the 2-inch soil depth reduced root growth but not shoot growth of crabgrass. Barley (Hordeum vulgare L., var. Trail) roots, like crabgrass, were more affected than shoots. Carbonyl labeled siduron-14C was absorbed by both barley roots and shoots. Siduron-14C was translocated from roots to shoots but not from shoots to roots. Analysis of the extracts from plants treated at various times revealed that no metabolites of siduron-14C were present. Siduron must be present at the time of seed germination to effectively reduce plant growth.
Herbicidal Phytotoxicity to Emerald Zoysia during Establishment
Authors: Smith G. S. , Callahan L. M.
Published: June 2019

A study of herbicides to aid in establishing an Emerald zoysia (Zoysia japonica x Zoysia tenuifolia Willd. ex Trin.) sod was initiated in the summer of 1965. Eleven herbicides were applied to Emerald zoysia sod-plugs newly planted in Emory clay loam soil. All of the herbicides provided excellent premergence control of crabgrass (Digitaria spp.) and goosegrass (Eleusine indica (L.) Gaertn.) throughout the growing season following treatments. Both 1-(2-methylcyclohexyl)-3-phenylurea (siduron) and O-(2,4-dichlorophenyl) O-methyl isopropylphosphoramido-thioate (DMPA) caused either no observable injury or only slight injury, thus causing no apparent chemical inhibition of growth and resulting in a rapid rate of establishment of the turfgrass. But N-(2-mercaptoethyl)benzenesulfonamide S-(O,O-diisopropyl phosphorodithioate) (bensulide) and 2,6-di-tert-p-tolyl-methylcarbamate (terbutol) severely injured Emerald zoysia; they seriously retarded the growth of the zoysia and greatly inhibited ground cover. Herbicides which effectively eliminated weed competition but which greatly retarded the growth of the turfgrass were more detrimental to establishment rate than the actual competition from weeds. These results indicate that selecting a herbicide safe to the turfgrass is more important than choosing a herbicide which only gives good weed control. However, indications are that some herbicides do combine the two important factors of safety and excellent weed control.
The Influence of Tillage Practices on Yields and Weed Control in Safflower
Authors: Fenster C. R. , Robison L. R.
Published: June 2019

An experiment to investigate tillage practices for producing safflower (Carthamus tinctorius L.) and controlling weeds was conducted from 1963 to 1965. Three tillage intensities designated excessive, moderate, and minimum, depending on the number and kind of tillage operations performed prior to planting, were used. Three different tillage tools used as the primary implement in preparing the seedbed were sweep machine, oneway, and moldboard plow.

Excessive, moderate, and minimum tillage plots averaged 342, 374, and 413 lb/A of safflower and 72, 73, and 63 lb/A of weeds, respectively. The sweep machine plots produced the highest safflower yields and lowest weed yields at all intensities with the oneway and moldboard plow about the same. Yields produced from the best treatments in the experiment (minimum tillage with the sweep machine and seeding with the shoe drill) averaged approximately 300 lb/A more than commercial fields and weed control was effective.
Herbicide Combinations for Woody Plant Control
Authors: Bovey R. W. , Davis F. S. , Morton H. L.
Published: June 2019

We studied 4-amino-3,5,6-trichloropicolinic acid (picloram) alone and in combination with 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) or 1,1′-dimethyl-4,4′-bipyridinium salt (paraquat) for control of several greenhouse, nursery, and natural-grown, woody plant species. Picloram:paraquat combinations improved the control of some species such as yaupon (Ilex vomitoria Ait.) as compared to picloram alone at equal rates; but it had an antagonistic effect on huisache (Acacia farnesiana (L.) Willd.) and honey mesquite (Prosopis juliflora (Swartz) DC. var. glandulosa (Torr.) Cockerell). Evaluation of picloram: 2,4,5-T combinations suggested that 2,4,5-T sometimes could be added in equal amounts to picloram to increase control or reduce picloram rates proportionately on huisache, honey mesquite and live oak (Quercus virginiana Mill.).
Persistence of Picloram Activity in Soil
Authors: Keys C. H. , Friesen H. A.
Published: June 2019

The persistence of 4-amino-3,5,6-trichloropicolinic acid (picloram) in soil was measured after varying periods of time up to 3 years with bioassay technique using sunflowers (Helianthus annuus L., var. Advent) as the indicator plant. Rates of application ranged from 0.5 to 48 oz/A on two soil types at Scott, Saskatchewan and two at Lacombe, Alberta. After 1 year, recovery ranged from 20 to 30% of the original application in the 0 to 9-inch depth in each soil not disturbed by tillage directly after application. Recovery of the herbicide applied at rates of 8 oz/A or higher in the fall declined to about 10% after 24 months and to 6% or less after 35 months for even the highest rates. Picloram activity generally was concentrated in the surface 6 inches, indicating limited downward movement due to water in each of the soils. However, there was a tendency toward greater downward movement in the soils having lower organic matter content.
Reaction of Western Ironweed Leaf Tissue to Picloram
Authors: Scifres C. J. , McCarty M. K.
Published: June 2019

Foliar treatments of 4-amino-3,5,6-trichloropicolinic acid (picloram) induced rapid procambium activity in western iron-weed (Vernonia baldwini Torr.) leaves. Increased meristematic activity was followed by destruction of the phloem parenchyma, sieve elements, and companion cells. Cell destruction in the vascular bundle was concomitant with that in the mesophyll.
Effects of Herbicides on the Capacity of Spring Parsley to Photosensitize Chickens
Authors: Williams M. Coburn
Published: June 2019

Spring parsley [Cymopterus watsonii (Coult. & Rose) Jones] was examined for phototoxicity by chick (Gallus domesticus, Arbor Acre 50 x Vantress hybrid) bioassay, after treatment with 2,4,-dichlorophenoxyacetic acid (2,4-D), 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), 4-amino-3,5,6-trichloropicolinic acid (picloram), and an approximate 4 to 1 mixture of 2,4-D and picloram. Spring parsley leaves treated with picloram and picloram-2,4-D were much less phototoxic to chicks than controls 4 weeks after treatment. When treatment was followed by warm weather, leaves treated with 2,4-D and 2,4,5-T were not phototoxic 4 weeks after treatment at the highest single dose that could be administered.
Translocation of Herbicides in Detached Bean Leaves
Authors: Leonard O. A. , Glenn R. K.
Published: June 2019

Labeled 2,4-dichlorophenoxyacetic acid (2,4-D), 2,4,5-trichlorophenoxyacetic acid (2, 4, 5-T), 2-methoxy-3,6-dichlorobenzoic acid (dicamba), 4-amino-3, 5, 6-trichloropicolinic acid (picloram), 1,2-dihydropyridazine-3,6-dione (MH), assimilates, and phosphoric acid were absorbed and transported basipetally from the lamina into the petioles of detached bean leaves (Phaseolus vulgaris L.). Upward transport in the lamina was slight, except when the petioles were in water. In contrast, labeled 3-(3,4-dichlorophenyl)-1,1-dimethylurea (diuron) was not transported basipetally, but some acropetal transport did occur. Vein-loading and transport of labeled assimilates, 2,4-D, dicamba, MH, and phosphate were greatly reduced by a prior treatment with 7-oxabicyclo(2.2.1)heptane-2,3-dicarboxylic acid (endothall). Detached leaves hold promise for use in absorption and transport studies.
Atrazine-Induced Ultrastructural Changes of Barnyardgrass Chloroplasts
Authors: Hill E. R. , Putala E. C. , Vengris J.
Published: June 2019

Electronmicrographs of barnyardgrass (Echinochloa crusgalli (L.) Beauv.) grown under controlled conditions and treated with 2-chloro-4-ethylamino-6-isopropylamino-s-triazine (atrazine) at the one to three-leaf stages show that degradation of the chloroplast starts as a swelling of the fret system followed by swelling and disruption of the granal discs. In advanced stages of breakdown, the membranes of the grana and chloroplast envelope were ruptured. These changes were initiated 2 hr after treatment with rates of 2, 5, 10, and 20 ppm atrazine. The incidence of starch grains greatly decreased as the duration of treatment exceeded 4 hr. The mitochondria appeared normal throughout, not being affected by concentration or duration of treatment. The stage of growth at which plants were treated was insignificant in determining changes at the ultrastructural level. The ultrastructural changes preceded any macroscopically discernable symptoms of tissue breakdown.
Dormancy, Longevity, and Germination of Seed of Three Larkspurs and Western False Hellebore
Authors: Williams M. Coburn , Cronin Eugene H.
Published: June 2019

Dormancy, longevity, and germination of seed of tall larkspur (Delphinium barbeyi Huth), duncecap larkspur (Delphinium occidentale S. Wats.), low larkspur (Delphinium nelsonii Greene), and western false hellebore (Veratrum californicum Durand) were investigated. Field studies were conducted in the Cache National Forest in Idaho at 8,000 ft elevation. With the exception of 12 of 400 buried duncecap larkspur seed, seed of all species in the longevity study germinated or disintegrated the first year under field conditions. No sound or viable seed was found at the end of the second year. Dormancy of most seed was broken in 13 to 19 weeks when seed were held at 33 to 34 F in moist sand in the laboratory or when seed were in contact with moist unfrozen soil under snow. Under optimum field conditions, the majority of the seed germinated by late March. Seedlings were well-established before snow-melt in June.
Differential Phytotoxicity of an Amiben Metabolite
Authors: Stoller E. W.
Published: June 2019

The differential phytotoxicity of an unidentified amiben conjugate (hereinafter referred to as amiben-X), obtained from giant foxtail (Setaria faberii Herrm.) treated with 3-amino-2,5-dichlorobenzoic acid (amiben) was tested in several plant species. Concentrations of amiben-X up to 10 ppm had no effect on radicle elongation in seedlings of soybean (Glycine max (L.) Merr.) or ivyleaf morningglory (Ipomoea hederacea (L.) Jacq.). Giant foxtail radicles were inhibited about 35% at 10 ppm. Amiben, amiben-X, and N-(3-carboxy-2,5-dichlorophenyl)-glucosylamine (hereinafter referred to as N-glucosyl amiben) were detected in seedling tissues of the three above species treated for 24 hr with 20 ppm amiben-X. The growth response of the plants to amiben-X probably resulted from the action of the amiben released by plant hydrolytic activity on amiben-X; amiben-X itself is considered to be relatively nonphytotoxic.
The Importance of the Shoot of Giant Foxtail for Uptake of Preemergence Herbicides
Authors: Knake Ellery L. , Wax Loyd M.
Published: June 2019

Herbicides were mixed with Drummer silty clay loam soil in 1-inch layers in the shoot, root, shoot and root, or seed zones for giant foxtail (Setaria faberii Herrm.). After 2 weeks in the greenhouse, foxtail tops were harvested and dry weights used as the measure of herbicidal effectiveness. All of the 11 herbicides evaluated caused a reduction in dry weight when placed in the shoot zone. When placed in the root zone, only 3-amino-2,5-dichlorobenzoic acid (amiben) caused a reduction in dry weight. Most herbicides were just as effective, or more so, in the shoot zone as in the seed zone. Only amiben and N-1-naphthylphthalamic acid (NPA) were more effective in the seed zone than in the shoot zone.
WSSA—Progress and Challenges
Authors: Behrens Richard
Published: June 2019

I AM most happy to signal the opening of the eighth meeting of the Weed Science Society of America, the first under our new name. Let me welcome you to New Orleans and to several days of stimulating meetings and discussions with your colleagues from Canada, Latin America, and the United States.
Influence of Siduron and its Degradation Products on Soil Microflora
Authors: Fields M. L. , Hemphill D. D.
Published: June 2019

The herbicide l-(2-methylcyclohexyl)-3-phenylurea (siduron) suppressed the growth of soil bacteria,Azotobacter sp.andChlorella vulgariswhereas siduron had no effect on actinomycetes, filamentous fungi, soil ciliates and other algae. Siduron had no effect upon the growth ofThiobacillus thioparus, Euglena gracilis, andStreptomyces griseus.The degradation product, 2-methylcyclohexylamine (hereinafter referred to as 2-MCHA) suppressed the growth ofAztobacter chroococcumand soil ciliates. Aniline, another degradation product of siduron, depressed the growth ofAspergillus versicolorandA. fischeri;however,A. ochraceus, A. candidus, A. clavatus, A. nidulans, A. flavus, Botrytis cinerea, andRhizopus nigricanswere not affected. None of these fungi was influenced in growth by 2-MCHA.Streptomyces griseusgrew significantly less in the presence of aniline. The growth ofChlamydomonas pyrenoidosa, C. radiata, Anabaena catenula, andRhizobium leguminosarumwere not influenced by 10 ppm aniline or 10 ppm 2-MCHA.
Chorella vulgaris Assay of the Activity of Soil Herbicides
Authors: Addison D. A. , Bardsley C. E.
Published: June 2019

An assay technique utilizing Chlorella vulgaris Beijerinck gave highly significant responses to low concentrations of aqueous 3-(p-chlorophenyl)-l,l dimethylurea (monuron), 3-(3,4-dichlorophenyl)-1,1-dimethylurea (diuron), and 2,4-bis(isopropylamino)-6-methylmercapto-s-triazine (prometryne) following 6 days of incubation. Water extracts of diuron from soil assayed with this organism were highly correlated with diuron added to the soil. Similar correlations for oats (Avena sativa L.) grown on the soil and for diuron in the water extracts as dichloroaniline serve to substantiate the relative effectiveness of the method. Assay of soil samples from field residue plots taken 150 days after herbicidal application showed that active residues of diuron and prometryne were detectable by the organism. Although the chemical method was faster, it has the disadvantage of measuring any dichloroaniline residues rather than only the active residues. The method developed insures a considerable saving in time over herbicide assays involving higher plants and gives reasonably good quantitative data on low concentrations of toxic monuron, diuron, and prometryne.
Trifluralin—Systemic Insecticide Interactions on Seedling Cotton
Authors: Arle H. Fred
Published: June 2019

In greenhouse experiments, soil-incorporated combinations of 0,0-diethyl S-[2-(ethylthio)-methyl]-phosphorodithioate (phorate) or 0,0-diethyl S-[2-(ethylthio)-ethyl]-phosphorodithioate (disulfoton) with a,a,a-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin) resulted in increased cotton (Gossypium hirsutum L.) seedling growth as compared to trifluralin used alone. This result apparently was due to the greater numbers of secondary roots in the zone of incorporation. Phorate was more effective than disulfoton in overcoming the inhibitory effect of trifluralin on secondary root development. A comparison of granular and emulsifiable phorate showed no advantage for either formulation. The combination of phorate and trifluralin in a 1-inch soil core, into which seeds of cotton were planted and surrounded by trifluralin-treated soil, also increased secondary root development as compared to using trifluralin alone.
A Relationship Between Foliar Symptoms and Tissue Content of Cucumbers Sprayed with Atrazine
Authors: Wong Melvin K. , Romanowski R. R.
Published: June 2019

Foliar applications of 2-chloro-4-ethylamino-6-isopropylamino-s-triazine (atrazine) at 0.05 to 1.0 lb/A caused characteristic injury symptoms on cucumber (Cucumis sativus L.) plants. Analytical methods were evaluated and found suitable in detecting atrazine in cucumber leaves sprayed at a low rate of 0.005 lb/A. For analytical detection, tissue samples should be taken as soon as necrotic symptoms appear, 4 to 7 days after suspected drift, and frozen immediately.
Loss of Herbicides in Runoff Water
Authors: Trichell D. W. , Morton H. L. , Merkle M. G.
Published: June 2019

The loss of 2-methoxy-3,6-dichlorobenzoic acid (dicamba), 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), and 4-amino-3,5,6-trichloropicolinic acid (picloram) in runoff water was determined with a gas chromatograph and bioassays. When determined 24 hr after application, losses of dicamba and picloram were greater from sod plots than from fallow plots while 2,4,5-T losses were about equal. Four months after application, losses of all herbicides averaged less than 1% of that lost 24 hr after application. The amount of picloram lost in a simulated rainfall of 0.5 inch varied with rate, but the percentage lost was the same. The slope of the plot and movement over untreated soil influenced the percentage of picloram lost. The maximum loss obtained for any herbicide was 5.5% and the average approximately 3%.
Effect of DCPA on Anatomy and Cytology of Roots
Authors: Bingham S. W.
Published: June 2019

Dimethyl 2,3,5,6-tetrachloroterephthalate (DCPA) on the soil surface inhibited rooting at bermudagrass (Cynodon dactylon L., var 328) stolon nodes. Histological studies of these root tips showed that cell division had ceased while cell enlargement continued for some time. Cells became excessively large and irregularly shaped. In corn (Zea may L., var. Pioneer 310), radicle cell size was about the same in both instances; however, treated tissue contained six times as many dinucleate cells as untreated radicle tissue. Numerous nuclei were at metaphase stage of mitosis in treated tissue. In untreated onion (Allium cepa L., var. Yellow Globe Danvers) root tips, many nuclei were found at anaphase and telophase stage of mitosis while very few cells were dividing in treated tissue.
Effect of Row Spacing on Weed Control in Soybeans
Authors: Wax L. M. , Pendleton J. W.
Published: June 2019

Field studies were conducted over a 2-year period at Urbana, Illinois, to evaluate soybean (Glycine max (L.) Merr., var. Harosoy 63 and Wayne) and weed yields as influenced by row spacing, variety, weed control methods, and 2,3,5-triiodobenzoic acid (hereinafter referred to as TIBA). Soybean yield increased and weed yield decreased as row spacing was decreased. Compared to the yield from 40-inch rows, soybean yield increase was 10, 18, and 20% for 30, 20, and 10-inch rows, respectively. Both cultivation and applications of a,a,a-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin) controlled annual grass weeds at all row spacings. Cultivation controlled broadleaf weeds at all row spacings. Some broadleaf weeds, unaffected by trifluralin, made sufficient growth to impair soybean yields in wide rows but not in narrow rows.
The Interactions of Soil-Borne Microorganisms and DCPA
Authors: Tweedy B. G. , Turner Nikki , Achituv Miriam
Published: June 2019

Soil samples with and without a past history of dimethyl-2,3,5,6-tetrachloroterephthalate (DCPA) treatment were obtained from New York. A third sample was obtained from a field in Colorado where DCPA had been ineffective as a herbicide. The populations of bacteria and actinomycetes in these soils were determined and the actinomycetes were more prevalent in the samples with previous DCPA treatment than in untreated samples. Subsequent treatment resulted in an increase in actinomycete population and little change in bacterial population. In pure culture and in soils, the addition of DCPA had no adverse effect upon microbial growth, and several microorganisms appeared to utilize the herbicide as a carbon source. Two degradation products were methyl-2,3,5,6-tetrachloroterephthalate and 2,3,5,6-tetrachloroterethalic acid.
Absorption, Translocation, and Metabolism of Prometryne in Cotton and Soybean
Authors: Sikka H. C. , Davis D. E.
Published: June 2019

Absorption, translocation, and metabolism of 14C-labeled 2,4-bis (isopropylamino)-6-methylmercapto-s-triazine (prometryne) from solution cultures by cotton (Gossypium hirsutum L., var. DPL smoothleaf) and soybean (Glycine max Merr., var. Lee) were investigated. Cotton (moderately tolerant) and soybean (sensitive) absorbed essentially equal amounts of prometryne. Whereas 14C was uniformly distributed in soybean, it was concentrated in the lysigenous glands and in the root primordia of cotton. Soybean had a considerably higher concentration of radioactivity in shoots than in roots, whereas the reverse was true in cotton. The major methanol extractable 14C-labeled component in the roots and shoots of both species was prometryne. Both species converted some prometryne to the derivative, 2,4-bis(isopropylamino)-6-hydroxy-s-triazine (hereinafter referred to as hydroxypropazine), but cotton shoots had a slightly higher percentage of the latter than the soybean shoots. The concentration of prometryne in soybean shoots was about four times greater than in cotton shoots. Differential translocation of prometryne appeared to be a major factor contributing to the difference in susceptibility between cotton and soybean.
Hygroscopic Additives to Phenoxy Herbicides for Control of Saltcedar
Authors: Hughes Eugene E.
Published: June 2019

Greenhouse studies on control of saltcedar (Tamarix pentandra Pall.), a problem phreatophyte, showed that when one of three hygroscopic compounds, polypropylenediol (a mixture of polypropylenediols with molecular weights ranging from 375 to 425) was added to water solutions of phenoxy herbicides, it significantly increased injury from most treatments. Injury to foliage from all herbicides tested, except the oil-soluble amine formulations (a mixture containing 80% tertiary dodecyl and 20% tertiary tetradecyl amine) of 2,4-dichlorophenoxyacetic acid (2,4-D), 2-(2,4,5-trichlorophenoxy) propionic acid (silvex), and 2,4-D plus 2,4,5-trichlorophenoxy acetic acid (2,4,5-T) (1:1), increased when polypropylenediol was added to the spray solution at 5% by volume. The increased activity was affected by the rate of the additive, temperature, humidity, and herbicide formulation.
Differential Response of Wild Oat Lines to Diallate, Triallate, and Barban
Authors: Jacobsohn Ruben , Andersen Robert N.
Published: June 2019

We evaluated 214 lines of wild oat (Avena fatua L.) for response to S-2,3-dichloroallyl N,N-diisopropylthiolcarbamate (diallate), S-2,3,3-trichloroaHyl N,N-diisopropylthiolcarbamate (triallate), and 4-chloro-2-butynl m-chlorocarbanilate (barban). We found large differences among the lines in response to these herbicides and some lines that might not be controlled by recommended rates of these herbicides. Frequency distributions of response to herbicides suggest that reaction to these three herbicides is quantitatively inherited. We were unable to establish a relationship between morphological characteristics and plant response to these herbicides.
Subsurface Application and Shallow Incorporation of Herbicides on Cotton
Authors: Wiese A. F. , Hudspeth E. B.
Published: June 2019

In a 3-year study on four soil types, subsurface application just ahead of a planter with a device that removed the top from the bed, applied a band of spray, and covered the band with soil reduced weed control in cotton (Gossypium hirsutum L.) obtained with 3-(3,4-dichlorophenyl)-1,1-dimethylurea (diuron), 2,4-bis(isopropylamino)-6-methylmercapto-s-triazine (prometryne), 3-(hexahydro-4,7-methanoindan-5-yl)-1,1-dimethylurea (norea), dimethyl-2,3,5,6-tetrachloroterephthalate (DCPA), and 1,1-dimethyl-3(α,α,α,-trifluoro-m-tolyl)urea (fluometuron) compared to applications on the soil surface. This machine improved weed control with α,α,α,-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin). Shallow incorporation, with two helical blades, after planting increased weed control with trifluralin, diuron, and DCPA by 10% or more over the surface applications. This incorporator increased weed control obtained with prometryne and norea 5%. Very shallow incorporation, with metal tines, after planting improved weed control obtained with trifluralin and DCPA 18 and 11%, respectively. Weed control with norea was increased 7%, but metal tines did not appreciably affect weed control obtained with prometryne, diuron, or fluometuron. Compared to surface applications, incorporation increased cotton injury with diuron, norea, prometryne, and fluometuron on sandy loam soil.
Herbicide-Induced Ethylene Production: Role of the Gas in Sublethal Doses of 2,4-D
Authors: Abeles F. B.
Published: June 2019

Ethylene production was stimulated by 2,4-dichlorophenoxyacetic acid (2,4-D) from light-grown corn (Zea mays L., var. XL-15) and soybeans (Glycine max Merr., var. Hawkeye). Ethylene had an inhibitory effect on the growth of corn and soybeans, but a reversal of the ethylene effect could not be clearly demonstrated using the competitive inhibitor, carbon dioxide. Ethylene did not mimic the ability of 2,4-D to cause growth curvatures. It was concluded that ethylene played a role in the activity of sublethal amounts of 2,4-D.
Competition of Wild Oat in Wheat and Barley
Authors: Bell Allyn R. , Nalewaja John D.
Published: June 2019

Wild oat (Avena fatua L.) competition increased the losses in yield of both wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) with increased densities of seedlings. At Fargo in 1965, wild oat densities of 70 and 160 seedlings/sq yd reduced the wheat yield 22.1% and 39.1%, respectively, compared to the wild oat-free check. Similar wild oat densities reduced the barley yield 6.5% and 25.9%, respectively. The addition of nitrogen and phosphorus fertilizer reduced the yield loss caused by wild oat 2 out of 3 years of the experiment. Although a considerable yield reduction occurred in barley and wheat, percent protein and seed size were not influenced noticeably.
Effect of Trifluralin on Roots of Corn and Cotton
Authors: Hacskaylo Joseph , Amato V. A.
Published: June 2019

Seed of corn (Zea mays L., var. Texas 28) and cotton (Gossypium hirsutum L., var. Deltapine smooth leaf) were planted in sand and subsequently drenched with solutions of α,α,α trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin). The levels of herbicide used inhibited growth of roots and shoots in both crops, but cotton proved more tolerant than corn. The roots failed to elongate normally, but the lateral growth that continued gave the radicle a “club-shaped” appearance, especially in corn. Stained sections of the roots were mounted as permanent slides for study. The cells at the extreme tip of the treated roots were small and dense; many were multinucleate. Immediately behind this region, the cells were abnormally large, thin-walled, and aberrant. A disorganized type of nuclear division was evident. Cell plate and cell wall formation were apparently rare. Although we found no normal sequence of mitosis in cells of treated roots, all stages of mitosis were seen in the untreated roots.
Metabolism of Amitrole in Excised Leaves of Canada Thistle Ecotypes and Bean
Authors: Smith L. W. , Bayer D. E. , Foy C. L.
Published: June 2019

Excised leaves of Canada thistle (Cirsium arvense (L.) Scop.) ecotypes and bean (Phaseolus vulgaris L., var. Red Kidney) metabolized 3-amino-l,2,4-triazole-14C (amitrole) to the same radiolabeled products, but they were produced at different rates as shown by thin-layer and paper chromatography. Bean leaves metabolized amitrole to a metabolic product (Unknown II) probably β-(3-amino-1,2,4-triazolyl-1-) α-alanine approximately three times taster than Canada thistle leaves, while Canada thistle converted Unknown II to another product (Unknown I) about 10 times faster than did bean. Thus Unknown II accumulated in bean, and Unknown I in Canada thistle. This reaction sequence in Canada thistle was evidently an irreversible consecutive first order reaction. A difference in the rate of metabolism was observed between susceptible and resistant ecotypes of Canada thistle.
Influence of Environmental and Chemical Factors on Amitrole Metabolism in Excised Leaves
Authors: Smith L. W. , Bayer D. E. , Foy C. L.
Published: June 2019

Several factors were studied which influenced 3-amino-1,2,4-triazole (amitrole) metabolism in excised leaves of bean (Phaseolus vulgaris L., var. Red Kidney) and Canada thistle (Cirsium arvense (L.) Scop.) ecotypes. Amitrole metabolism in the leaves of both species held in the light was greater than in leaves held in the dark. Increasing the temperature from 15 C to 28 C also stimulated the rate of metabolism of amitrole. However, this effect was much less pronounced when the temperature was increased from 22 C to 28 C. Dipping the leaves in 10−2M ammonium thiocyanate reduced the metabolism of amitrole, whereas similar pre-treatment with 3.5 × 10−3M 6N-benzyladenine enhanced the metabolism of amitrole.
Chemical Fallow of Abandoned Croplands on the Short-Grass Plains
Authors: Hyder D. N. , Everson A. G.
Published: June 2019

Chemical-fallow experiments were initiated as a possible means of improving summer-fallow procedures for seedbed preparation and rehabilitation of abandoned croplands subject to wind erosion. Red threeawn (Aristida longiseta Steud.) and sand dropseed (Sporobolus cryptandrus (Torr.) Gray) are pioneer perennial grasses that have stabilized these sandy loam soils but are undesirable forage plants. Dimethylarsinic acid (cacodylic acid), 2-tert-butylamino-4-ethylamino-6-methylthio-5-triazine (GS-14260), and a mixture of 3-amino-l,2,4-triazole (amitrole) plus ammonium thiocyanate were ineffective, but 2,2-dichloropropionic acid (dalapon) applied at 6 lb/A or more reduced these pioneer perennial grasses 80 to 100%. Follow-up treatments, either mechanical or chemical, are needed to maintain control of competing vegetation while seeded species become established.
Vapor Pressures of Low-Volatile Esters of 2,4-D
Authors: Flint G. W. , Alexander J. J. , Funderburk O. P.
Published: June 2019

The vapor pressures of the four most common commercial low-volatile esters and a reference high-volatile ester of 2,4-dichlorophenoxyacetic acid (2,4-D) were determined by gas-liquid chromatography. The order of increasing volatility and the vapor pressure of these esters in mm of Hg at 187 C are as follows: isooctyl—2.7; 2-ethylhexyl—3.0; butoxy ethanol—3.9; propylene glycol butyl ether—3.9; and the reference, isopropyl—16.7. Extrapolations to 25 C support this ranking at working temperatures. Commercial esters of 2,4-D derived from long-chain hydrocarbon alcohols are in the same volatility range as the commercial esters containing an ether linkage.
Phytotoxicity of Demethylated Analogs of Diphenamid
Authors: Gentner W. A.
Published: June 2019

The phytotoxicity ofN,N-dimethyl-2,2-diphenylacetamide [diphenamid],N-methyl-2,2-diphenylacetamide, 2,2-diphenylacetamide, and 2,2-diphenylacetic acid was studied on tomatoes [Lycopersicon esculentumMill.], common lambsquarters [Chenopodium albumL.], redroot pigweed [Amaranthus retroflexusL.], and rape [Brassica napusL.], by means of nutrient solution culture techniques. Diphenamid was the most phytotoxic; 2,2-diphenylacetic acid was the least active. Only minor differences in the arithmetical means of the phytotoxicity indices existed in the phytotoxicity of theN-methyl and amide analogs of diphenamid.
Effects of Growth Regulators and Herbicides on Germination of Hydrilla Turions
Authors: Steward Kerry K.
Published: June 2019

Turions of Hydrilla verticillata (Casp.) were treated with gibberellic acid (GA), napthaleneacetic acid (NAA), indoleacetic acid (1AA), 2-chloroethane phosphonic acid, 6,7-dihydrodipyrido(1,2,-a:2′, 1′-c)-pyrazinediium salts (diquat), 1,1′dimethyl-4,4′-bipyridinium salts (paraquat), mono-N,N-dimethylcocoamine salt of 7-oxabicyclo (2.2.1)heptane-2,3-dicarboxylic acid (cocoamine salt of endothall), or the dimethyl amine formulation of 2,4-dichlorophenoxyacetic acid (2,4-D). Germination and growth of subterranean turions was enhanced by GA and axillary turions by 1AA and 2,4-D. The herbicides exhibited little phytotoxicity to the propagules.
A Device for Threshing Mesquite Seed
Authors: Flynt T. O. , Morton H. L.
Published: June 2019

We modified a cereal huller to thresh seed of honey mesquite [Prosopis juliflora (Swartz) DC. var. glandulosa (Torr.) Cockerell]. The device threshes seed of other mesquite varieties, huisache [Acacia farnesiana (L.) Willd.], and other leguminous species.
Effect of Soil Water Stress and Soil Temperature on Translocation of Diuron
Authors: Sedgley R. H. , Boersma L.
Published: June 2019

Rates of photosynthesis, respiration, and transpiration of wheat (Triticum aestivum L., var. Gaines) were determined as functions of time, under controlled conditions of moderate soil water stress and soil temperature, after treatment of the roots with 3-(3,4-dichlorophenyl)-1,1-dimethylurea (diuron). Air temperature, relative humidity, light intensity, and air movement were maintained constant. The rate of photosynthesis declined with time for all plants treated with diuron but not for the controls. No change in the rate of respiration was detected. The rate of transpiration decreased slightly immediately upon application of the diuron and then remained constant. The data indicate that soil temperature and soil water stress play important roles in the herbicidal action of diuron applied to the soil.