bluuebunny/crossref_metadata_2025 huggingface dataset:
The Fate of 2,4-D Applied to Viking Birdsfoot Trefoil and a Resistant Intercross
Authors: Blacklow W. M. , Linscott D. L.
Published: June 2019

The fate of the potassium salt of 2,4-dichlorophenoxyacetic acid (2,4-D) when applied to birdsfoot trefoil (Lotus corniculatus L., var. Viking) and an intercross resistant to 2,4-D was studied. No difference in spray retention per mg fresh weight between the two trefoils was detected and more than 98% of 2,4-D-2-14C was absorbed within 2 days after application. Herbicide moved from treated leaves to young leaves, stems, and roots in about equal quantities. Seven days after treatment, 70% of the 14C activity of 2-propanol extracts of both trefoils was 2,4-D-2-14C; the remaining activity of the extract was from unknown metabolites of 2,4-D. The total activity recovered from the tolerant selection and Viking, respectively, was 57% and 50% of that applied. The methods used failed to establish a clear basis for the difference in reaction of the two birdsfoot trefoils to 2,4-D.
Herbicidal Influence on Amylase in Barley and Squash Seedlings
Authors: Penner Donald
Published: June 2019

The development of amylase activity controlled by the embryo in the distal halves of intact barley (Hordeum vulgareL., var. Larker) seeds during the first 2 days of germination was prevented by the presence in the culture solution of 10−4M 7-oxabicyclo-(2.2.1)heptane-2,3-dicarboxylic acid (endothall), 3,5-dibromo-4-hydroxybenzonitrile (bromoxynil), 2,6-dichlorobenzonitrile (dichlobenil), or 3 amino-2,5-dichlorobenzoic acid (amiben) and was not overcome by the simultaneous addition of gibberellic acid. The aforementioned herbicides did not inhibit gibberellic acid-induced amylase synthesis in de-embryonated halved barley seeds. The amiben and bromoxynil inhibition of barley germination was slightly reduced by the simultaneous addition of 10−2M glucose to the culture solution. Amiben and bromoxynil also inhibited the development of low levels amylase activity found in 2-day-old squash (Cucurbita maximaDuchesne, var. Chicago Warted Hubbard) cotyledons; however, added benzyladenine overcame the inhibition. In contrast to barley, benzyladenine was shown to induce the development of amylase activity in squash. Tolerance of squash and other seeds low in carbohydrates to amiben and bromoxynil during germination may be related to their independence from herbicide-inhibited carbohydrate degradation for energy and carbon source required for anabolic processes.
Species Differences in Site of Root Uptake and Tolerance to EPTC
Authors: Oliver L. R. , Prendeville G. N. , Schreiber M. M.
Published: June 2019

We studied the uptake of ethyl N,N-dipropylthiocarbamate (EPTC) by barley (Hordeum vulgare L.), wheat (Triticum aestivum L.), oats (Avena sativa L.), sorghum (Sorghum vulgare Pers.), and giant foxtail (Setaria faberii Herrm.) using a double plastic pot technique that allowed separate exposure of the shoot and root zones to treated soil. Barley was more tolerant than wheat, whereas oats, sorghum, and giant foxtail were the most susceptible to EPTC at 1/4 to 1 1/2 lb/A-inch. The roots were the major site of uptake in barley, but injury to the other species from root exposure was equal to or slightly less than that from shoot exposure. The seed, or first 2 to 4 mm of shoot or both, were more sensitive in wheat than in barley. Such differential sensitivity was not evident in the shoot zone of the other species. These experiments, coupled with 14C-EPTC studies, indicated that differences in tolerance can be associated with the sites of uptake.
Species Differences in Site of Shoot Uptake and Tolerance to EPTC
Authors: Prendeville G. N. , Oliver L. R. , Schreiber M. M.
Published: June 2019

We determined the effects of ethylN,N-dipropylthiocarbamate (EPTC) in soil placed at different shoot zones of barley (Hordeum vulgareL.), wheat (Triticum aestivumL.), oats (Avena sativaL.), and sorghum (Sorghum vulgarePers.) below the soil surface after emergence. A wax-barrier allowed separate exposure of the shoot zones to treated soil. Wheat, barley, and oats were severely injured when treated at the coleoptilar internode. Exposure of the remaining shoot did not affect growth. Sorghum was severely injured regardless of the shoot zone exposed. On this basis, sorghum was the most susceptible, while wheat, barley, and oats were equally tolerant. Uptake of14C-EPTC from the soil by the sorghum shoots was double that of wheat, a fact which might explain the differential susceptibilities. These studies indicate that growth responses of species to EPTC applied to shoots is dependent on the stage of plant development at which treatment occurs.
Displacement of Fluometuron and Diuron through Saturated Glass Beads and Soil
Authors: Davidson J. M. , Santelmann P. W.
Published: June 2019

Solutions containing 3-(m-trifluromethylphenyl)-l,l-di-methylurea (fluometuron) or 3-(3,4-dichlorophenyl)-1,1-dimethylurea (diuron) were displaced through saturated 250-μ glass beads or through Norge loam soil at two water flow rates. The procedure used allowed uniform application of herbicide solutions to the soil surface and subsequent displacement of the herbicide through soil or glass bead columns at a constant water flow rate. Fluometuron was as mobile as the chloride ion at both high and low flow rates. The shape of the fluometuron distribution curves obtained at the two flow rates were distinctly different. The volume of water required to displace fluometuron through a material that adsorbed the herbicide was greater than that necessary to displace the fluometuron through materials giving a smaller amount of adsorption. More diuron was adsorbed by the glass bead system than fluometuron.
Minutes of the Business Meeting: Weed Science Society of America
Authors: Danielson L. L.
Published: June 2019

The meeting was called to order by President Richard Behrens at 4:35 p.m.
Effect of Time of Giant Foxtail Removal from Corn and Soybeans
Authors: Knake Ellery L. , Slife Fred W.
Published: June 2019

With a corn (Zea mays L.) yield of 144 bu/A on weed-free plots, giant foxtail (Setaria faberii Herrm.) reduced corn yields 1, 2, 5, 7, and 18 bu/A, respectively, when removed when 3, 6, 9, and 12 inches high and at maturity. With a soybean (Glycine max L.) yield of 30 bu/A on weed-free plots, the same treatments reduced soybean yields 0, 0, 1, 2, and 18 bu/A, respectively. Giant foxtail competing with corn delayed tassel emergence but had little effect on moisture of grain or on shelling percent at harvest. The total dry matter produced per acre remained relatively constant whether the dry matter was made up of corn alone or corn and weeds. The greatest competitive effect of giant foxtail with soybeans occurred after the reproductive stage of soybeans began or after the weeds became sufficiently dense to reduce the light which soybeans received. Early-season competition had greater effect on corn than on soybeans. However, the taller growing corn competed better than soybeans with giant foxtail later in the season.
Response of Tropical Vegetation to Herbicides
Authors: Bovey R. W. , Dowler C. C. , Diaz-Colon J. D.
Published: June 2019

Several herbicides and herbicide combinations were investigated for desiccation, defoliation, and killing of tropical vegetation near Mayaguez, Puerto Rico. Hydroxydimethylarsine oxide (cacodylic acid) was one of the more effective defoliants on guava (Psidium guajavaL.) within 2 weeks after treatment. However, several herbicide combinations including contact: growth-regulator types were more effective 1 month after spraying. Six months after treatment, herbicides containing (2,4-dichlorophenoxy)-acetic acid (2,4-D), (2,4,5-trichlorophenoxy)acetic acid (2,4,5-T), or 4-amino-3,5,6-trichloropicolinic acid (picloram) were superior to contact herbicides in controlling regrowth. In a mixed tropical forest, most rapid desiccation and defoliation of vegetation was produced by 6,7-dihydrodipyrido (1,2-a:2′,1′c) pyrazinediium salt (diquat) within 2 weeks after treatment. At 1 month after treatment and longer, the 1:1 mixture of the butyl ester of 2,4-D:2,4,5-T and a 2:2:1 mixture of the isooctyl esters of 2,4-D:2,4,5-T:picloram were superior to other herbicides.
Accurately Predicting a Herbicide's Potential
Authors: Whitworth J. W. , Anderson W. P.
Published: June 2019

Field screening methods were developed which proved very reliable in accurately assessing the potential of herbicides during the first year of testing. Under conditions imposed by these methods, the herbicides usually exhibited maximum toxicity, thereby indicating which ones might be potentially hazardous in growers' fields when crop tolerance is lowered by adverse growing conditions. Of the 29 crop uses suggested by the data, 16 are registered by the USDA and are now in current use. Of these 29, 26 were indicated during the first year of testing and substantiated by data from an additional 1 to 4 years of testing.
Absorption and Penetration of Picloram in Potato Tuber Discs
Authors: Swanson C. R. , Baur J. R.
Published: June 2019

Discs of potato (Solanum tuberosum L.) tuber tissue were immersed in buffered (pH 4.0 to 8.0) solutions of 4-amino-3,5,6-trichloropicolinic acid (picloram) (5 × 10−4M to 5 × 10−3M) for 1 to 36 hr. Uptake of picloram during incubation, and leakage after return of the discs to untreated buffer, were determined by gas chromatographic analysis of extracts of the tissue and ambient buffer. Picloram absorption increased with concentration and with time up to 24 hr. Maximum uptake occurred at pH 4.0 and very little picloram was absorbed at pH 7.0 and 8.0. Both absorption and leakage were temperature dependent. The rate and extent of leakage was greatest at the highest concentration. Typically, more than 90% of the picloram absorbed from 5 × 10−3M was lost to fresh buffer within 12 hr.
Light Intensity and the Absorption and Translocation of 2,4,5-T by Woody Plants
Authors: Brady Homer A.
Published: June 2019

Absorption of the isooctyl ester of (2,4,5-trichlorophenoxy)-acetic acid varied more than 20% in four woody species when incident light intensity was increased from 40 to 4,000 ft-c. Variations in translocation of the herbicide of 45 to 50% in post oak (Quercus stellataWangenh.) and water oak (Quercus nigraL.) accompanied changes in illumination. Light intensity did not affect translocation in longleaf pine (Pinus palustrisMill.) or American holly (Ilex opacaAit.)
Influence of Weed Competition on Sorghum Growth
Authors: Burnside O. C. , Wicks G. A.
Published: June 2019

Weed competition in this experiment had a more marked effect on sorghum [Sorghum bicolor (L.) Moench, var. RS 610] grain yields than did row spacings or sorghum populations. Sorghum grown in 20-inch, as compared to 40-inch, rows had higher grain and stover yields and lower weed yields and 1000-seed weight. Sorghum populations of 42,000 to 50,000 plants per acre produced higher grain and stover yields than populations of 26,000 to 28,000 plants per acre which had greater weed yields, heads per plant, seed weight per head, seed moisture at harvest, and 1000-seed weight. In hand weeded plots, sorghum yields were not affected by row spacing or sorghum population; but as weed competition increased, sorghum yields increased with narrower rows and higher plant populations. Sorghum yields were reduced 4, 12, and 18% by delaying weeding of plots 3, 4, and 5 weeks as compared with 2 weeks after planting. Weeds that did not emerge until 4 weeks after planting did not reduce sorghum yields.
EPTC Effects on Sicklepod Petiolar Fatty Acids
Authors: Wilkinson R. E. , Hardcastle W. S.
Published: June 2019

Total petiolar fatty acid content of sicklepod (Cassia obtusifoliaL.) treated with 0, 0.14, 0.28, 0.56, 1.12, 2.24, or 4.48 kg/haS-ethyl dipropylthiocarbamate (EPTC) was measured by gas-liquid chromatography. Neither total petiole fatty acid content nor percentages of the various 53 identified constituents changed in relation to herbicide application. Isostearate (17.5%), stearate (5.7%), oleate (5.7%), linolate (9.8%), and arachidate (8.2%) accounted for 46.9% of the total petiole fatty acid content. Anteiso derivatives of C15to C31were identified and quantitated at concentrations of 0.25 to 2.00%. Petiole cuticle thickness decreased 35% as herbicide concentration increased to 4.48 kg/ha.
Biochemical Basis for Plant Competition
Authors: Black C. C. , Chen T. M. , Brown R. H.
Published: June 2019

A survey has been made of the literature on biochemical characteristics of plants with particular emphasis on factors affecting photosynthesis. From these characteristics, plants have been divided into two groups, efficient and non-efficient. This division is justified on the basis of data published by numerous workers. A hypothesis has been developed that efficient plants often have been used in agriculture because of their high production, but efficient plants also are very competitive and the observation has been made that almost all weeds which have been tested are members of the efficient groups of plants. This hypothesis is discussed and some general conclusions have been advanced related to plant breeding, development of herbicides to inhibit specific biochemical reactions, ecology, and increasing food production.
Chemical Stimulation of Ethylene Evolution and Bud Growth
Authors: Morgan Page W. , Meyer Robert E. , Merkle Morris G.
Published: June 2019

A formulation containing 2-chloroethanephosphonic acid, its ethyl ester and anhydride (hereafter referred to as 66-329), caused defoliation and, subsequently, growth of inactive basal buds of honey mesquite [Prosopis juliflora var. glandulosa (Torr.) Cockerell]. With huisache [Acacia farnesiana (L.) Willd.], the same treatments increased the number of branches and leaves per node; however, apical buds often were killed. Application of 66-329 to mesquite increased the release of ethylene to levels in the experimental system which were physiologically active. Bud release by 66-329 appeared to be mediated by ethylene. Treatments that induce growth of basal and lateral buds of woody plants may allow the killing of more plants by subsequent herbicide application.
Control of Live Oak by Herbicides Applied at Various Rates and Dates
Authors: Bovey R. W. , Morton H. L. , Baur J. R.
Published: June 2019

Herbicides 4-amino-3,5,6-trichloropicolinic acid (picloram) and 5-bromo-3-sec-butyl-6-methyluracil (bromacil) effectively controlled live oak (Quercus virginianaMill.) when applied in the spring and fall in south Texas. A mixture of picloram plus (2,4,5-trichlorophenoxy)acetic acid (2,4,5-T) also was effective. Higher rates of bromacil were required than for picloram or picloram plus 2,4,5-T for effective control. Bromacil was more injurious to herbaceous vegetation. The phenoxy herbicides (2,4-dichlorophenoxy)acetic acid (2,4-D) and 2,4,5-T were ineffective.
Reaction of Flax to Dicamba Applied at Several Stages
Authors: Nalewaja John D.
Published: June 2019

Flax (Linum usitatissimum L., var. Bolley) was susceptible very early, when less than 2 inches tall, 1965 only, and during flowering, to 3,6-dichloro-o-anisic acid (dicamba) as determined from 9 consecutive weekly applications in the field in 1965 and 1966. Dicamba decreased flaxseed yield, percent oil and iodine number of the oil, seed size, seed germination, and plant height, and increased the days to maturity by application at either one or both of the susceptible stages of flax.
Selective Control of Plains Pricklypear in Rangeland with Herbicides
Authors: Wicks G. A. , Fenster C. R. , Burnside O. C.
Published: June 2019

Experiments were conducted at Crawford and Kimball, Nebraska, during 1962, 1963, 1964, and 1965 to determine the effect of 13 herbicides on plains pricklypear (Opuntia polyacantha Haw.). The best control was obtained with 2-(2,4,5-trichlorophenoxy)propionic acid (silvex), 4-amino-3,5,6-trichloropicolinic acid (picloram), 3,6-dichloro-o-anisic acid (dicamba), and (2,4,5-trichlorophenoxy) acetic acid (2,4,5-T). Silvex and picloram were superior to dicamba and 2,4,5-T in controlling plains pricklypear, but picloram and dicamba injured the native grasses. Rotary hoeing plains pricklypear cladodes just prior to spraying improved herbicide performance. Simulated railing was not a consistent control measure. Evaluation of plains pricklypear control was made 1 and 2 years after herbicide application.
Translocation and Metabolism of MAA-14C in Johnsongrass and Cotton
Authors: Sckerl M. M. , Frans R. E.
Published: June 2019

Radioautographs showed that root uptake of14C-methanearsonic acid (MAA-14C) by johnsongrass (Sorghum halepense(L.) Pers.) from nutrient solution was rapid and translocation into all portions of the plant occurred within 4 hr after treatment. Basipetal and acropetal translocation of foliar and stem-applied MAA-14C occurred in both johnsongrass and cotton (Gossypium hirsutumL., var. Rex smooth leaf), indicating that movement of the herbicide probably occurs in both phloem and xylem tissue. However, acropetal movement of MAA in both plants occurred at a higher rate than basipetal movement, and basipetal movement in cotton was not as rapid as in johnsongrass. Methanol extracts of MAA-14C johnsongrass were chromatographed. Radioactive spots with Rfvalues different from the MAA-14C standard were observed. Use of location reagents on the chromatographs suggested that MAA-14C may complex with either a sugar or organic acid or both. Amino acid fractions were prepared from methanol extracts of both plants. An MAA metabolite, with a positive reaction to ninhydrin, was located on chromatographs spotted with the amino acid fraction from johnsongrass but was not present in the cotton fraction. A comparison of Rfvalues suggests that the metabolite may be a combination of the MAA molecule with histidine or one of its analogues. Spectrophotometric determination showed a build-up of amino acids in MAA-treated johnsongrass but not in cotton. The increased levels of amino acids in johnsongrass suggest that the MAA metabolite may be blocking a protein synthesis pathway, or some other unknown biosynthetic pathway.
Paraquat Soil Bonding and Plant Response
Authors: Tucker B. V. , Pack D. E. , Ospenson J. N. , Omid A. , Thomas W. D.
Published: June 2019

The toxicity of 1,1'-dimethyl-4,4'-bipyridinium ion (paraquat) in soil can be related to the degree of bonding strength to the soil aggregates. Tightly bound material is unavailable to plants, while loosely bound material can be potentially available to plants. On the basis of growth of corn (Zea maysL., var. Golden Cross Bantam) and beans (Phaseolus vulgarisL., var. Idaho 1-11) in sand, loamy sand, loam, and muck treated with paraquat, it is concluded that planned and careful application would not lead to accumulation of lethal dosages in medium to heavy soils.
Weed Control in Sugarbeets with Herbicides and Cultivation
Authors: Wicks G. A. , Anderson F. N.
Published: June 2019

The effects of five herbicide and three in-the-row cultivation treatments on weed control and sugarbeet (Beta vulgaris L.) yield were studied at Mitchell and North Platte, Nebraska, during 1966 and 1967. Preplant soil incorporation treatments of 5-amino-4-chloro-2-phenyl-3(2H)-pyridazinone (pyrazon) + N,N,dimethyltri-decylamine salt of 7-oxabicyclo[2.2.1]heptane-2,3-dicarboxylic acid (endothall), and S-ethyl N-ethylthiocyclohexanecarbamate (cycloate), and postemergence application of pyrazon + 2,2-dichloropropionic acid (dalapon) resulted in better weed control and more sucrose per acre than S-propyl butylethylthiocarbamate (pebulate) applied preplant and soil-incorporated, and the untreated check treatment. Herbicide-treated plots kept weed-free by handweeding did not differ from the handweed check in sucrose production. Rotary hoeing improved weed control and increased sucrose yields as compared to flextine harrowing and the no in-the-row cultivation treatment.
Effect of Pyriclor on Mitochondrial Oxidation
Authors: Killion D. D. , Frans R. E.
Published: June 2019

The effect of 2,3,5-trichloro-4-pyridinol (pyriclor), as well as carbonyl cyanide m-chlorophenyl hydrazone, 2,4-dinitrophenol, and oligomycin, on oxygen uptake and oxidative phosphorylation was investigated with mitochondria isolated from hypocotyls of etiolated soybeans (Glycine max Merrill, var. Lee). Pyriclor inhibited both coupled and uncoupled reactions. This suggests that pyriclor either acts on a nonphosphorylating intermediate close to the electron carrier chain or with a component of the electron carrier chain, or both.
Gains in Timothy Forage from Goldenrod Control with 2,4-D, 2,4-DB, and Picloram
Authors: Peters E. J. , Lowance S. A.
Published: June 2019

Postemergence applications of 0.5 and 1.0 lb/A of a potassium salt of 4-amino-3,5,6-trichloropicolinic acid (picloram) killed all or nearly all of the goldenrod (Solidago nemoralis Ait.) growing with timothy (Phleum pratense L.). Two lb/A of butoxy ethanol ester or dimethylamine salt of (2,4-dichlorophenoxy)acetic acid (2,4-D), and 1 and 2 lb/A of butoxy ethanol ester of 4-(2,4-dichlorophenoxy) butyric acid (2,4-DB) reduced yields of goldenrod 75 to 95%. Lower rates of herbicides were relatively unsatisfactory for controlling goldenrod. Timothy was not injured by the herbicides and yields increased 0.8 and 1.0 lb for each 1.0 lb of weeds that failed to grow.
Self-Propelled Combine for Harvesting Research Plots
Authors: Burnside O. C.
Published: June 2019

A modification of an 8-ft, self-propelled combine for harvesting research plots of soybeans (Glycine maxL.), sorghum [Sorghum bicolor(L.) Moench], and small grains is described. The combine facilitates efficient and precise harvesting of yield plots with considerable savings in time and labor.
Incorporation of Preplant Herbicides for Cotton
Authors: Wiese Allen F. , Chenault E. Wayne , Hudspeth Elmer B.
Published: June 2019

Studies conducted from 1964 to 1967 on three soil types indicated that α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin), dimethyl tetrachloroterephthalate (DCPA), and 4-(methylsulfonyl)-2,6-dinitro-N,N-dipropylaniline (nitralin) applied preplant and incorporated with two tandem diskings in March or April prior to bedding, gave excellent control of a mixture of Amaranthus sp. and volunteer sorghum (Sorghum bicolor (L.) Moench) in cotton (Gossypium hirsutum L.) planted in early May. Cotton was not stunted and yields were not appreciably reduced. When trifluralin was applied, soil residues the next year dictated that sorghum planting be delayed until May.
Interaction of Linuron and Row Spacing for Control of Yellow Foxtail and Barnyardgrass in Soybeans
Authors: Kust Cyril A. , Smith R. R.
Published: June 2019

Field studies were conducted during 1967 and 1968 at the University of Wisconsin Experimental Farm, Arlington, Wisconsin, to determine the comparative effectiveness of combinations of row spacings and rates of 3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea (linuron) for control of yellow foxtail (Setaria glauca(L.) Beauv.) and barnyardgrass (Echinochloa crusgalli(L.) Beauv.) in soybeans (Glycine max(L.) Merr.). Soybean yields and weed control increased as row spacing decreased. Lower rates of linuron were required for comparable weed control as row spacing decreased. Yield increases with decreasing row width were much greater in 1968 than in 1967, probably because of better rainfall during July, August, and early September in 1968. Improved weed control in the narrow rows may have been due partially to absorption by soybean leaves of light wavelengths that may be most favorable for photosynthesis and vegetative growth of some weed species.
Distribution of Root-Absorbed Picloram
Authors: Baur J. R. , Bovey R. W.
Published: June 2019

We studied changes in the concentration of 4-amino-3,5,6-trichloropicolinic acid (picloram) with time in roots, stems, and leaves of 20-day-old seedlings of huisache (Acacia farnesiana (L.) Willd.) and honey mesquite (Prosopis juliflora (Swartz) DC. var. glandulosa (Torr.) Cockerell). Exposing root systems to aqueous solutions of picloram (1.0 ppm huisache and 10.0 ppm honey mesquite) for 24 hr killed approximately 60% of the treated plants. In honey mesquite, picloram was redistributed and eventually lost over a 5-day period, whereas neither redistribution nor loss occurred in huisache.
Effects of 2,4-D on Seed Production and Embryo Development of Curly Dock
Authors: Maun M. A. , Cavers P. B.
Published: June 2019

Lithium salt of (2,4-dichlorophenoxy)acetic acid (2,4-D) (1000 ppm) was sprayed on plants of curly dock (Rumex crispus L.) 12 days before anthesis, at an thesis, 7 days after anthesis, and 34 days after anthesis. Treatment 12 days before anthesis completely prevented the formation of viable seeds. Two percent of the seeds had minute embryos after treatment at anthesis, but even these seeds did not germinate. Embryos were present in 91% of the seeds from plants treated 7 days after anthesis. These embryos ranged in size from 0.5 to 2.5 mm. The total weight of seeds obtained was significantly less than the control and only 5 to 15% of these seeds were capable of germination. Spraying the inflorescences 34 days after anthesis did not affect the number of seeds produced or seed viability. Almost all plants remained alive after the harvest.
Plant and Soil Arsenic Analyses
Authors: Wilkinson R. E. , Hardcastle W. S.
Published: June 2019

Neutron-activation analyses of arsenic were reproducibly quantitative at 10 ng As and might be extended as low as 3 ng As with extended counting periods. The method was tested on soil and cotton (Gossypium hirsutum L., var. Atlas 67) leaves treated with repeated applications of monosodium methanearsonate (MSMA). Leaves from untreated plants contained 55 ng As/g whereas leaves from treated plants showed higher levels of arsenic. Translocation of As was demonstrated and analysis of arsenic in the soil was valid.
Granular Herbicides for Woody Plant Control
Authors: Bovey R. W. , Morton H. L. , Baur J. R. , Diaz-Colon J. D. , Dowler C. C. , Lehman S. K.
Published: June 2019

Granular 4-amino-3,5,6-trichloropicolinic acid (picloram) was effective in controlling live oak(Quercus virginiana(Mill.), huisache)(Acacia farnesiana(L.), Willd.), and yaupon(Ilex vomitoriaAit.), but not honey mesquite(Prosopis juliflora(Swartz) DC. var.glandulosa(Torr.) Cockerell) in south Texas. Granular 5-bromo-3-sec-butyl-6-methyluracil (bromacil) controlled live oak and huisache. Herbicides applied to soil were usually most effective in spring and fall during periods of active brush growth. Picloram granules applied in May to a mixed stand of woody plants in Puerto Rico usually were effective. However, rates up to 30 lb/A were ineffective on some species.
Equipment for Incorporation of Herbicides
Authors: Bode L. E. , Gebhardt M. R.
Published: June 2019

Evaluations were made of the α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin) distribution patterns produced by eight incorporating implements. The power rotary cultivator concentrated the trifluralin in the top inch when operating at a 4-inch depth, while the disk, operated at the same depth, concentrated the trifluralin at a point 2 to 3 inches below the surface. All the remaining implements resulted in more than 80% of the recovered trifluralin in the top inch, except for isolated treatments with the Richardson and Lilliston tools. Surface applications resulted in less trifluralin recovery than from any implement. The disk resulted in the highest recovery and was two to three times greater than the recovery from the surface application. The recovery from the Richardson, Lilliston, and Ro-Wheel was 1.5 to 2 times greater than the recovery from the Mix-A-Product, field cultivator, and spike harrow.
Picloram Enhances 2,4-D Movement in Field Bindweed
Authors: Agbakoba Chuma S. O. , Goodin J. R.
Published: June 2019

Field bindweed (Convolvulus arvensisL.) was sprayed with a mixture of (2,4-dichlorophenoxy)acetic acid (2,4-D) and 4-amino-3,5,6-trichloropicolinic acid (picloram). A mixture of picloram and 2,4-D each at 0.01 lb and 0.001 lb/A killed tops of plants faster than 2,4-D alone or picloram alone at the same rates. Higher rates of 1 lb/A picloram plus 1 lb/A 2,4-D and 0.1 lb/A picloram plus 0.1 lb/A 2,4-D were not consistently synergistic or antagonistic. The percent of plants which produced new growth were 0 for picloram alone at 1 lb/A, 20 for a mixture of 2,4-D and picloram each at 1 lb/A, and 40 for 2,4-D alone at 1 lb/A. Other rates of 0.1 lb/A, 0.01 lb/A, and 0.001 lb/A did not control regrowth of field bindweed. Application of unlabeled picloram simultaneously with14C-2,4-D increased translocation of14C-2,4-D, but the reverse was not true.
Absorption, Distribution, and Metabolism of Linuron in Corn, Soybean, and Crabgrass
Authors: Nashed R. B. , Ilnicki R. D.
Published: June 2019

The fate of 3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea (linuron) in greenhouse-grown juvenile corn (Zea maysL., var. N. J. 9), soybean (Glycine max(L.) Merr., var. Kent), and crabgrass (Digitaria sanguinalis(L.) Scop.) was investigated. Linuron entered the plants from nutrient solution with the water absorbed. A small but measurable amount of the herbicide was found in the tissue as 3-(3,4-dichlorophenyl)-1-methoxyurea and as 3,4-dichloroaniline. A materials balance between linuron uptake and acetone extractable linuron plus metabolites found could not be achieved. Evidence is presented for the presence of “bound” linuron which accounted for from 15 to 25% of the herbicide absorbed.
Quackgrass and Nitrogen Effects on Succeeding Crops in the Field
Authors: Kommedahl Thor , Old K. M. , Ohman J. H. , Ryan E. W.
Published: June 2019

Plant heights and seed yields of oats (Avena sativa L.), corn (Zea mays L.), and soybeans (Glycine max (L.) Merr.) were lower where these crops followed a heavy infestation of quackgrass (Agropyron repens (L.) Beauv.) than when they followed oats or fallow land. Application of ammonium nitrate (280 kg/ha) only partially corrected the adverse effect on yield of a previous quackgrass infestation. The effect of quackgrass persisted through the second growing season as measured by height and yield of wheat (Triticum aestivum L.) and compared with wheat after oats, corn, soybeans, or fallow, but the effect of nitrogen applied the first year only did not persist through the second year.
Factors Influencing Commercial Aerial Applications of 2,4,5-T
Authors: Eaton B. J. , Elwell H. M. , Santelmann P. W.
Published: June 2019

Data were collected on 36 variables including application, environmental, edaphic, and plant conditions during a 3-year study of aerial brush control treatments at 79 sites. These then were correlated with defoliation responses of blackjack oak (Quercus marilandicaMuenchh.) and post oak (Quercus stellataWangenh.) to (2,4,5-trichlorophenoxy)acetic acid (2,4,5-T). The stage of oak growth was of primary importance in obtaining maximum defoliation with 2,4,5-T; the oaks were most susceptible 6 to 8 weeks after the last killing frost. Air temperatures above 90 F, relative humidity below 60%, poor spray coverage and swath widths greater than 50 ft significantly reduced defoliation by 2,4,5-T. Total rainfall during the month before spray application was positively correlated with defoliation by 2,4,5-T, but correlations with rainfall for other time intervals before and after spraying were not significant. Wind above 6 mph at the time of treatment slightly reduced 2,4,5-T effectiveness, but wind direction and dew at spray time did not influence herbicide activity. Application rates of less than 1.75 lb/A were not as effective as higher rates. Aircraft design, spray-water carrier constituents, soil type, soil depth, soil temperature, and topography had no apparent influence on defoliation of oaks by 2,4,5-T.
Foliar Penetration of Picloram and 2,4-D in Aspen and Balsam Poplar
Authors: Sharma M. P. , Born W. H. Vanden
Published: June 2019

Added surfactant (Atlox 210) at 1% (v/v) and high relative humidity enhanced the penetration of both 4-amino-3,5,6-trichloropicolinic acid (picloram) and (2,4-dichlorophenoxy)acetic acid (2,4-D) into detached leaves of aspen poplar (Populus tremuloides Michx.). The influence of added surfactant was greater for picloram and the dimethylamine of 2,4-D than for the ethyl or butoxyethanol ester of 2,4-D. Penetration of picloram and the dimethylamine of 2,4-D occurred more readily from the abaxial than from adaxial surfaces of leaves. The ethyl ester of 2,4-D penetrated equally readily from both leaf surfaces. Penetration of picloram and the dimethylamine of 2,4-D from the adaxial surface of leaves occurred readily in young leaves in early June. There was an increase in penetration in early July followed by a decrease in August and September to a level equal to or less than that in June. Penetration from the abaxial surface of leaves was nearly equal in June and July, but there was a gradual decrease in August and September. An increase in temperature from 10 to 25.5 or to 40.5 C resulted in a sharp increase in penetration of both picloram and 2,4-D under both low and high relative humidity. Autoradiographic evidence showed that movement of picloram within the leaf also was much more extensive at the higher temperatures. Partial removal of cuticular waxes from the adaxial surface of leaves with chloroform resulted in up to four-fold increases in penetration of picloram and 2,4-D. Differences in penetration rate of picloram between leaves of aspen poplar and balsam poplar (Populus balsamifera L.) did not account for reported differences in susceptibility between these two species.
Weed Science in a Crop Protection Program
Authors: Bendixen Leo E. , Herr D. E. , Stroube E. W. , Alban E. K. , Waldron A. C.
Published: June 2019

An increasingly urgent need exists for men, broadly yet specifically, trained in the areas of crop protection. Crop protection includes weed control, insect control, plant disease control, and pesticide analysis. The need extends across teaching, research, development, sales, application, management, and other areas encompassed by crop protection. Administrative and financial advantages may result from the development of this type of program. Curricula for the BS, MS, and PhD degrees have been developed which offer a broad base of crop protection but allow pursuit of the degree from (or specialization in) any of the areas of crop protection. At the same time, however, chemistry and physiology form the disciplinary basis of all science curricula and the focal point is graduate training. Four courses relevant to all areas of crop protection and five additional courses in weed science have been developed.
Dormancy and Sprouting Cycles of Wild Garlic
Authors: Stritzke J. F. , Peters E. J.
Published: June 2019

Field studies of seasonal sprouting of wild garlic (Allium vineale L.) bulbs showed that all the soft offset, aerial, and central bulbs sprouted, but only 20 to 34% of the hardshell bulbs sprouted after a short after-ripening period. Each fall, a percentage of the remaining hardshell bulbs sprouted, but after 4 years 16% of the hardshell bulbs were still dormant. Embryonic shoots of all bulb types sprouted when excised following the after-ripening period. In addition to a short after-ripening period, hardshell bulbs had a prolonged dormancy due to some mechanism which resides in, or was controlled by, the tissue surrounding the embryonic shoot.
Germination Control of Johnsongrass Rhizome Buds
Authors: Hull Richard J.
Published: June 2019

Field-harvested johnsongrass (Sorghum halepense(L.) Pers.) rhizomes were assayed for bud dormancy and growth potential under a number of experimental conditions. Natural dormancy was not detected in single-node rhizome pieces harvested at any time of the year. Shoot growth rates were highly variable. Kinetin, benzyl adenine, gibberellic acid, and 2-chloroethylphosphonic acid were ineffective in enhancing germination or normalizing shoot growth. Scale leaves of rhizomes had no effect on bud growth. Rhizome buds were strongly influenced by apical dominance and emerged shoots partially suppressed germination of adjacent buds. The optimum temperature for bud germination and shoot growth was approximately 30 C. Bud germination was suppressed at 15 C. Johnsongrass rhizomes failed to exhibit cold hardiness at any time in their life cycle.
Combinations of Herbicides and other Pesticides on Soybeans
Authors: Johnson B. J.
Published: June 2019

The growth of soybean (Glycine max (L.) Merr.) seedlings was retarded when treated with either methyl 3-amino-2,5-dichlorobenzoate (amiben methyl ester) or α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin) when compared with soybeans treated with either 3-[-p-(p-chlorophenoxy)phenyl]-1,1-dimethylurea (chloroxuron) or 3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea linuron. Seedling growth of soybeans also was retarded when treated with amiben methyl ester alone or applied in combination with O,O-diethyl S[2-(ethylthio)ethyl] phosphorodithioate (disulfoton). Insecticides did not influence growth of soybeans. Linuron applied in combination with O,O-diethyl S-[(ethyl-thio)methyl] phosphorodithioate (phorate). or methyl-N-[(methylcarbamoyl)oxy] thioacetimidate (methomyl) and amiben ester applied in combination with phorate produced significantly lower seedling vigor during only 1 year than when each pesticide was applied alone. Soybean stands were significantly lower only in 1 year when linuron was applied in combination with methomyl. None of the pesticides applied alone or in combination caused significant differences in date of maturity, lodging, seed yield, seed size, or seed quality during either year.
Reserve Carbohydrate Storage and Utilization by Yellow Rocket, White Cockle, and Hoary Alyssum
Authors: Hastings R. E. , Kust Cyril A.
Published: June 2019

Total nonstructural carbohydrate (hereinafter referred to as TNC) storage in roots and utilization of TNC by yellow rocket (Barbarea vulgarisR. Br.), white cockle (Lychnis albaMill.), and hoary alyssum (Berteroa incana(L.) DC) was studied through a 1-year life cycle in plants seeded July 8, July 22, and August 5, 1966. For yellow rocket, TNC storage was most rapid during September and reached maximum levels by November 2. Younger plants stored TNC more efficiently than did older plants, but total grams of TNC per plant were greater for older plants than for younger plants. No plants bolted during the seeding year. Rapid declines in TNC of the roots began in late March, and minimum TNC levels coincided with the completion of flowering in mid-June for all plants the year after seeding. For white cockle, TNC storage was most rapid during September and early October, and reached maximum levels for all plants by November 2. There was no apparent winter injury to any of the plants. Total growth in 1967 was greatest for plants seeded July 8 and least for plants seeded August 5. Flowering began June 2 and seed were mature June 29. Adventitious buds were present on the roots of all plants on all sampling dates from September 7, 1966, through July 7, 1967. Minimum levels of TNC during spring growth were reached in mid-June. For hoary alyssum, TNC storage was most rapid during late September and October and reached maximum levels by the middle of November. TNC levels were higher in plants seeded July 22 or August 5 than in those seeded July 8. Plants seeded July 8 were flowering profusely by the middle of September, those seeded July 22 were flowering October 6, but those seeded August 5 did not flower in the seeding year. In 1967, all plants were in full bloom May 26. Minimum TNC levels were reached at full bloom and there was no accumulation of TNC as of July 7.
Effect of Aerially-Applied Herbicides on Texas and Puerto Rico Forests
Authors: Dowler Clyde C. , Tschirley Fred H. , Bovey R. W. , Morton H. L.
Published: June 2019

We applied (2,4-dichlorophenoxy)acetic acid (2,4-D), (2, 4,5-trichlorophenoxy)acetic acid (2,4,5-T), 4-amino-3,5,6-trichloropicolinic acid (picloram), and 1,1′-dimethyl-4,4′-bipyridinium ion (paraquat) alone and in various combinations by aircraft on arborescent species in Texas and Puerto Rico. Paraquat defoliated trees rapidly but did not give long-term control. Picloram defoliated a greater number of species than the other herbicides and defoliation extended over a longer period. No treatment killed all trees in the mixed forest or prevented regrowth and secondary succession for a period of more than 1 year. Higher herbicide rates were necessary to defoliate woody plants in tropical Puerto Rico than in subtropical Texas.
Uptake and Translocation of 2,4-D-1-14C in Parrotfeather
Authors: Sutton David L. , Bingham S. W.
Published: June 2019

Root applications of (2,4-dichlorophenoxy)acetic acid (2,4-D) at concentrations of 2.5 × 10−8M or higher inhibited growth of emersed parrotfeather (Myriophyllum brasilienseCamb.). There was little acropetal movement after applications of 1.1 × 10−5M 2,4-D-1-14C to the roots of emersed parrotfeather. When the metabolic inhibitor dinitrophenol at concentrations of 10−3or 10−4M was root-applied concomitantly with 10−8M 2,4-D-1-14C, there was an acropetal movement of radioactivity in the transpiration stream to the plant shoot. Basipetal movement occurred in the phloem after applications of 2.2 μg 2,4-D-1-14C to mature leaves in the shoot center of emersed parrotfeather.
The Effect of Auxin on Sprouting in Poison Ivy
Authors: Sterrett J. P. , Foy C. L. , Bingham S. W.
Published: June 2019

Experiments were conducted on poison ivy (Rhus radicans L.) to determine the effect of auxin on the formation of sprouts. Stump sprouting occurred where poison ivy propagules were decapitated. The influence of the shoot could be replaced by applying indoleacetic acid (hereinafter referred to as IAA) in lanolin paste to the cut surface of the stump. When the paste was removed after inhibiting stump sprouting for a month, sprouts formed within 35 days. This evidence supports the apical dominance theory of stump sprouting. When IAA-2-14C in lanolin was applied to the cut surface of the root stump, autoradiographs showed that 14C activity was concentrated where the majority of stump sprouts would develop, and chromatography of an extract indicated the presence of an auxin oxidation product of IAA. Dialyzed enzyme preparations from poison ivy stumps oxidized IAA in a Warburg apparatus which demonstrated that an IAA oxidizing system was present.
Utility of Maintained Weed Infestations Under Field Conditions
Authors: Upchurch R. P. , Selman F. L. , Webster H. L.
Published: June 2019

Relatively pure stands of eight weed species were maintained under field conditions on a Goldsboro loamy sand at Lewiston, North Carolina, for all or part of a 6-year period. Herbicides evaluated as preemergence surface treatments for these species were 2-sec-butyl-4,6-dinitrophenol (dinoseb), isopropyl m-chlorocarbanilate (chloropropham), 3-(3,4-dichlorophenyl)-1,1-dimethyl-urea (diuron), 2-chloro-4,6-bis(ethylamino)-s-triazine (simazine), and 3-amino-2,5-dichlorobenzoic acid (amiben). S-ethyl dipropylthiocarbamate (EPTC) and a,a,a-trifluro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin) were evaluated as preemergence incorporated treatments. The first four herbicides were evaluated in 1961, 1964, and 1966 while the last three were evaluated in 1962, 1963, and 1965. A series of rates was used for each chemical with three replications. With the exception of diuron which failed to control goosegrass (Eleusine indica (L.) Gaertn.), all of the herbicides provided at least a moderate degree of control of goosegrass, smooth crabgrass (Digitaria ischaemum (Schreb.) Muhl.), and redroot pigweed (Amaranthus retroflexus L.) at the respective typical field use rates. In general, trifluralin and amiben gave the best grass control and dinoseb the poorest. None of the herbicides effectively controlled common cocklebur (Xanthium pensylvanicum Wallr.) or ivyleaf morningglory (Ipomoea hederacea (L.) Jacq.). Trifluralin and EPTC did not control Pennsylvania smartweed (Polygonum pensylvanicum L.), common ragweed (Ambrosia artemisiifolia L.), and common lambsquarters (Chenopodium album L.). Chloropropham was ineffective on common ragweed. Simazine, chloropropham, and amiben controlled Pennsylvania smartweed while diuron, simazine, dinoseb, and amiben were especially effective on common lambsquarters. Distinctive patterns of nematode infestations were observed as a function of weed species.
A Mist Chamber for the Culture of Plants or Explant Segments
Authors: Beasley C. A. , Fox W. P.
Published: June 2019

Versatile mist chambers, framed with aluminum and glass and having access from top and sides, permit culture of an extensive number of, and different types of, vegetative plant organs as well as seeds and plant pathogens. Pneumatic atomizing nozzles are staggered to permit division of the chamber, and the spray emitted can be regulated from each nozzle. The amount of water vapor emitted is regulated by changing the air pressure or siphon height. Gauge-monitored pressure regulators and solenoid valves control the air and spray system. Timing devices can be used to inject water vapor at desired intervals. Air passing through a condensation tube is recycled past cone heaters, providing temperature from ambient to 90 F, and a duct and baffle system provides uniformity of temperature throughout. A combination recorder and controller maintains the desired temperature.
The Effect of Frost on the Response of Spring Wheat to 2,4-D
Authors: Bradbury I. K. , Ashford R.
Published: June 2019

The possibility of an interaction between (2,4-dichlorophenoxy)acetic acid (2,4-D) and frost-injured plants of spring wheat (Triticum aestivum L., var. Manitou) was investigated. Application of 2,4-D was made either a few hours prior to the frost or at varying periods following the frost. Although there was no statistical evidence of any interaction between the frost and 2,4-D, yields of grain tended to be lowest when plants were exposed to both frost and herbicide. On the basis of results obtained, it was concluded that there is no great risk of severe damage occurring to frost-damaged spring wheat plants if they are treated with 2,4-D within a short period of being exposed to frost.
Paraquat for Range Seeding in Cismontane California
Authors: Kay Burgess L. , Owen Richard E.
Published: June 2019

A technique was developed for seeding rangelands which are too steep or too rocky to seed by current methods. Hardinggrass (Phalaris tuberosa L. var. stenoptera (Hack.) Hitchc.) and subclover (Trifolium subterraneum L.) were established by seeding immediately after spraying the resident vegetation with 1,1′-dimethyl-4,4′-bipyridinium ion (paraquat). Tested for seeding in sod were single-disk, double-disk, and hoe-type drill openers. The double disk was best adapted to the clay soils most common in the area. A heavy-duty rangeland drill was modified with custom-made, heavy, double-disk openers and equipped with a spray system which sprays either bands or full coverage. The resulting planter will kill weeds, plant seeds, and spread fertilizer any place where a crawler tractor can pull it. Weed-free bands of 6 and 12 inches were compared with full spray coverage. No hardinggrass was established without some weed control. In only 5 of 16 tests over a 5-year period was full-spray coverage superior to the 6-inch band. The 12-inch band or full spray may be preferable on shallow soils or soils of low water-holding capacity. Spraying helped establish subclover but, unlike with hardinggrass, was not critical. Grazing or mowing during the establishment period improved stands of both hardinggrass and subclover. Prolonged weed control made paraquat superior to cultivation by giving better weed control and a firmer seedbed.
Movement and Distribution of Pyrazon in Soil
Authors: Smith D. T. , Meggitt W. F.
Published: June 2019

Two months after 5-amino-4-chloro-2-phenyl-3(2H)-pyridazinone (pyrazon) application (2.7 kg/ha), 80 to 100% of the total residue (1.3 to 4.2 μg/g) was in the upper 5 cm of soil. Herbicide movement occurred in soils that contained 3.8% organic matter or less. Pyrazon did not move below 10 cm or accumulate in soil as a result of movement. Adsorption of pyrazon was related to soil organic matter content (r = 0.90) and accounted for differences in herbicide movement previously observed. Calculations of pyrazon movement, based on soil organic matter content, coincided with depths of movement observed under field conditions.