bluuebunny/crossref_metadata_2025 huggingface dataset:
Weed Seed Germination Under Simulated Drought
Authors: Hoveland C. S. , Buchanan G. A.
Published: May 2019

Seeds of five crop and 17 weed species were germinated with 0, 3, 6, and 10-bar water solutions of polyethylene glycol to simulate drought. With simulated drought, most weed species germinated better than soybeans (Glycine maxL. ‘Hampton 266A’) but were not equal to pearlmillet [Pennisetum typhoides(Burm.) Stapf. and C. E. Hubb ‘Millex 23’] or sorghum-sudangrass [Sorghum bicolor(L.) Moench xS. sudanense(Piper) ‘SX-16’]. Prickly sida (Sida spinosaL,), sicklepod (Cassia obtusifoliaL.), andIpomoea lacunosaL. were the most tolerant weed species to simulated drought. Four species were intermediate in tolerance and four species germinated poorly under simulated drought. Hemp sesbania [Sesbania exaltata(Raf.) Cory] was the least tolerant and was similar to soybean.
Fate of Picloram in Canada Thistle, Soybean, and Barley
Authors: Sharma M. P. , Vanden Born W. H.
Published: May 2019

Autoradiography and radioassay results indicated that14C-picloram (14C-4-amino-3,5,6-trichloropicolinic acid) was absorbed and translocated rapidly in Canada thistle [Cirsium arvense(L.) Scop.], soybean [Glycine max(L.) Merr. ‘Harosoy 63’], and barley (Hordeum vulgareL. ‘Parkland’) following foliar or root application. Foliar absorption was much faster and more complete in soybean and Canada thistle than in barley. The radioactivity from14C-picloram accumulated in shoot meristems in Canada thistle and soybean, whereas in barley it was distributed throughout the plant following uptake by foliage or roots. Decarboxylation of14C-picloram by foliarly-treated Canada thistle, soybean, and barley plants did not occur in appreciable amounts. Chromatographic analysis of ethanol extracts of plants treated with14C-picloram up to 20 days revealed no evidence of picloram metabolism by these plant species. It is concluded that differences in absorption and in distribution patterns of picloram after shoot or root uptake contribute greatly to the expression of its selective action in the species studied.
Absorption, Translocation, and Metabolism of Alachlor by Yellow Nutsedge
Authors: Armstrong Thomas F. , Meggitt William F. , Penner Donald
Published: May 2019

The main site of uptake of soil-applied 2-chloro-2′, 6′-diethyl-N-(methoxymethyl) acetanilide (alachlor) by yellow nutsedge (Cyperus esculentusL.) plants is the portion of the plant above the tuber. Primarily acropetal and some basipetal14C translocation occurred from14C-alachlor applications to seedlings with shoots 2 to 4 cm in length. Alachlor is metabolized rapidly in yellow nutsedge to at least one water-soluble metabolite. Applications of14C-alachlor to shoots 15 cm in length resulted in limited acropetal14C translocation.
Are Herbicides too Expensive?
Authors: Green M. B.
Published: May 2019

We hear the expression “cost-benefit” a great deal nowadays; and when we do, we should always ask “cost to whom? Benefit to whom?” We should also remember that cost-benefit analysis requires that account be taken not only of financial gains and losses but also of all advantages and disadvantages of any kind. Consideration only of income and expenditure is investment appraisal, and many of the so-called “cost-benefit” studies of herbicide usage which have been published come into this category. Such studies are useful, but they should not be considered in isolation from investment appraisal of herbicide discovery, development, and production for the manufacturer; and both must be integrated into a total view of cost-benefit of weed control for the whole community, a broad and long-term view which takes account not only of economic values but also of social values. To make decisions and to formulate policies which will set herbicides in an optimum way in the social and economic context of an entire community and which will produce the most favourable cost-benefit for that whole community demands study and analysis of the total system. In the short time allocated to me I can do no more than skim over this wide field and indicate a number of relevant topics, and I plead guilty in advance to the charge of being superficial and of suggesting things that should be done without describing in detail how they could be done. My remarks will apply to the developed countries because the herbicide needs of the under-developed countries are a separate subject.
Herbicidal Activity and Metabolism of Dyrene in Canada Thistle
Authors: Marriage P. B.
Published: May 2019

The fungicide, Dyrene [2,4-dichloro-6-(o-chloroanilino)-s-triazine], severely injured var.miteof Canada thistle [Cirsium arvense(L.) Scop.]; and the damage resembled that caused by bipyridylium herbicides. Regrowth from treated plants was abnormal. Other arylamino-s-triazines were from slightly to severely phytotoxic to leaf sections of the var.mite.The var.horridumof Canada thistle was not affected by Dyrene or related compounds. Dyrene and metabolites of Dyrene which were phytotoxic to var.miteleaf disks in bioassay tests were isolated from treated var.miteandhorridumplants, but none of these compounds injured the var.horridum.One metabolite was found only in the var.mite; the other five occurred in both varieties. The metabolites were apparently formed from Dyrene by conjugation reactions.
Weeds and Alfalfa Hay Quality
Authors: Cords H. P.
Published: May 2019

Established stands of alfalfa (Medicago sativa L. ‘Lahontan’) at six field locations were treated with soil-active herbicides during the dormant period for the control of winter annual weeds. Weeds and alfalfa were hand separated at the first harvest. This forage, which varied widely in weed content, was analyzed for protein. The percentage of protein correlated negatively with weed content in all cases. Analyses of covariance revealed that the direct effect of the herbicides on protein content was either small or absent and that the primary cause of the negative correlations was weed content.
Adsorption and Degradation of Chlorbromuron in Soil
Authors: Savage K. E.
Published: May 2019

The adsorption-desorption equilibria of chlorbromuron [3-(4-bromo-3-chlorophenyl)-1-methoxy-1-methylurea] in soil conformed to the Freundlich equation. Values of the constants,kandn, ranged from 4.2 to 12.3 and from 1.2 to 2.5, respectively, in eight soils. No significant linear correlation was detected between the Freundlich k values and soil texture, organic-matter content, pH, or water-holding capacity. Degradation studies were conducted using14C-carbonyl-radiolabeled chlorbromuron in soil incubated at 18 or 32 C, with and without prior autoclaving, and with and without glucose enrichment. Degradation was enhanced by the higher temperature and glucose amendment, and it was retarded by autoclaving. Thin-layer chromatography indicated no accumulation of the monomethyl or monomethoxy derivative of chlorbromuron in any of the treatments. Chlorbromuron degraded rapidly in the incubation studies. Rapid loss of phytotoxicity was also noted in a greenhouse study with cucumber (cucumis sativusL. ‘Explorer’) bioassay. Phytotoxicity from 4 ppmw chlorbromuron had diminished to a very low level after 12 weeks.
Differential Response of Ditchbank Grasses to Herbicides
Authors: Hodgson J. M.
Published: May 2019

Herbicides were evaluated for selectivity between three tall coarse grasses and three short fine grasses. Reed canarygrass (Phalaris arundinaceaL.), quackgrass [Agropyron repens(L.) Beauv.], and smooth brome (Bromus inermisLeyss) were consistently more susceptible to amitrole-NH4CN (3-amino-s-triazole-ammonium thiocyanate) than three desirable short grasses, Kentucky bluegrass (Poa pratensisL.), creeping red fescue (Festuca rubraL.), and redtop (Agrostis albaL.). Reed canarygrass and redtop were more susceptible to dalapon (2,2-dichloropropionic acid) than creeping red fescue. Amitrole-NH4CN and dalapon combinations were more toxic to reed canarygrass, smooth brome, and redtop than creeping red fescue. Pyriclor (2,3,5-trichloro-4-pyridinol) was quite toxic to all grasses with Kentucky bluegrass showing the most tolerance. When TCA (trichloroacetic acid) was combined with amitrole-NH4CN results were similar to the dalapon combination but overall toxicity was reduced.
Control of Woody Plants with Herbicide Mixtures
Authors: Meyer R. E. , Bovey R. W.
Published: May 2019

Honey mesquite [Prosopis juliflora(Swartz) DC. var.glandulosa(Torr.) Cockerell], huisache [Acacia farnesiana(L.) Willd.], Macartney rose (Rosa bracteataWendl.), live oak (Quercus virginianaMill.), and whitebrush (Aloysia lycioidesCham.) were sprayed with herbicides alone and in mixtures. Mixtures of picloram (4-amino-3,5,6-trichloropicolinic acid) + dicamba (3,6-dichloro-o-anisic acid) at 0.56 + 0.56 and 1.12 + 1.12 kg/ha were most effective for killing honey mesquite in July. Picloram or picloram + dicamba were more effective for defoliating huisache than 2,4,5-T [(2,4,5-trichlorophenoxy)acetic acid], dicamba, or other mixtures of herbicides. On Macartney rose picloram as the salt or ester was most effective, but some mixtures of picloram plus either 2,4-D [(2,4-dichlorophenoxy)acetic acid] or 2,4,5-T were as effective as picloram alone. On live oak, the most effective treatments generally contained at least 1.12 kg/ha of picloram either alone or in mixtures with dicamba or 2,4,5-T. Picloram alone killed as many or more whitebrush plants than MCPA [[(4-chloro-o-tolyl)oxy]acetic acid], dicamba, 2,4,5-T, 2,4-D, or mixtures.
Lipid Metabolism as a Site of Herbicide Action
Authors: St. John J. B. , Hilton J. L.
Published: May 2019

Dinoseb (2-sec-butyl-4,6-dinitrophenol) and MBR 8251 [1,1 1-trifluoro-4′-(phenylsulfonyl)-methanesulfono-o-toluidide] inhibited enzymic synthesis of glycerides in vitro. The physiological significance of this inhibition was confirmed in intact wheat [Triticum aestivumL., ‘Mediterranean’ (C.I. 5303)] seedlings; dinoseb and MBR 8251 inhibition of glyceride synthesis in vivo was evidenced by a buildup in free fatty acids and a decrease in neutral and polar lipids. Glyceride synthesis and growth were reduced approximately equally by dinoseb and MBR 8251. However, polar (membrane) lipids were reduced more drastically than growth. It is suggested that dinoseb and MBR 8251 alter membrane structure and function through an inhibition of membrane lipid synthesis. DNP (dinitrophenol) was only slightly inhibitory in either the in vitro or in vivo system. Dinoseb was more effective than MBR 8251 in destruction of cell membrane permeability of intact roots immediately after treatment.
Controlled Release of Herbicides—Theory
Authors: Collins R. L. , Doglia S. , Mazak R. A. , Samulski E. T.
Published: May 2019

The concept of controlled release of herbicides has created in some workers expectations beyond possibility. In this theoretical paper, we examine the results to be expected based on a simplistic model. The purpose of the development is that it serve as a guide to experimentation and as a stimulant to such experimentation by revealing the possible advantages which may occur.
Metabolism of 2-(α-naphthoxy)-N,N-diethyl propionamide in Tomato
Authors: Murphy J. J. , Didriksen Janice , Gray R. A.
Published: May 2019

Metabolism of the herbicide 2-(α-naphthoxy)-N,N-diethyl propionamide (R-7465) by tomato plants (Lycopersicon esculentum Mill. ‘Mechanical Harvester’) was investigated. Ring-labeled R-7465-14C was taken up rapidly by the roots and distributed throughout the leaves within 8 hr. R-7465 was converted primarily into water soluble metabolites. The principal metabolite was identified as a hexose conjugate of 2-(α-naphthoxy-4-hydroxy)-N,N-diethyl propionamide. This metabolite represented 47% of the soluble radioactivity in the plant. A different hexose conjugate of 2-(α-naphthoxy-4-hydroxy)-N,N-diethyl propionamide together with a hexose conjugate of 2-(α-naphthoxy-4-hydroxy)-N-ethyl propionamide accounted for another 22% of the radioactivity. Nonmetabolized R-7465 was found to represent only 5% of the total soluble radioactivity. Other identified metabolites included 2-(α-napthoxy)-N-ethyl propionamide, 2-(α-naphthoxy-5-hydroxy)-N,N-diethyl propionamide, and 1,4-naphthoquinone. None of these metabolites individually represented more than 3% of the soluble radioactivity in the plants. Ring hydroxylation and N-dealkylation appeared to be the initial steps in detoxification of R-7465 followed by conjugation with sugars.
Translocation and Metabolism of Benazolin in Wild Mustard and Rape Species
Authors: Schafer D. E. , Stobbe E. H.
Published: May 2019

The fate of 4-chloro-2-oxobenzothiazolin-3-ylacetic acid (benazolin) in wild mustard [Brassica kaber(DC.) L.C. Wheeler var.pinnatifida(Stokes) L.C. Wheeler], turnip rape (Brassica campestrisL. ‘Echo’), and rape (Brassica napusL. ‘Target’) was investigated with the aid of14C-benazolin. The label was more mobile in wild mustard than the rape species following leaf treatment and accumulated in young leaves, stem, and stem apex. The label was also found in foliage after root treatment. In both cases, the translocated label was primarily that of14C-benazolin, implying phloem and xylem transport. The susceptibility of wild mustard and tolerance of the rape species to foliar-applied benazolin can be partly explained by different rates of transport to susceptible meristematic sites. Root exudation of the label following leaf treatment was greater in wild mustard than in the rape species and was not correlated with selectivity. Labeled benazolin was rapidly metabolized by theBrassicaspecies to four derivatives which appear to be less toxic than benazolin. Specific differences in metabolism were not sufficient to explain selectivity. Negligible amounts of14CO2were released by the three species following treatment with14C-benazolin.
Bromacil and Picloram under Southern Upland Hardwoods
Authors: Peevy Fred A.
Published: May 2019

Bromacil (5-bromo-3-sec-butyl-6-methyluracil) was much more effective in killing post oak (Quercus stellata Wangenh.) and blackjack oak (Q. marilandica Muenchh.) trees than 4-amino-3,5,6-trichloropicolinic acid (picloram) when applied to soil at 5.6 and 11.2 kg/ha in spots, bands, or by broadcasting. When applied at 5.6 kg/ha in bands or broadcast, picloram effected better crown reduction than bromacil on mockernut hickory (Carya tomentosa Nutt). Differences between rates and methods of applying bromacil were small. While bromacil was superior on the prevalent overstory species, post oak and blackjack oak, picloram excelled on the most numerous understory plants.
Soil Water and Growth of Rice and Weeds
Authors: Smith Roy J. , Fox W. T.
Published: May 2019

In pot culture experiments in the greenhouse, rice [Oryza sativaL. ‘Nova 66’], red rice [O. sativaL.], barnyardgrass [Echinochola crus-galli(L.) Beauv.], broadleaf signal-grass [Brachiaria platyphylla(Griseb.) Nash], northern jointvetch [Aeschynomene virginica(L.) B.S.P.], and hemp sesbania [Sesbania exaltata(Raf.) Cory] were seeded 1.3, 2.5, 5.1, and 10.2 cm deep in Crowley silt loam which was held at field capacity (24% moisture), saturation (34% moisture), or submerged 1.3 or 5.1 cm. At field capacity and saturation all species seeded 1.3, 2.5, and 5.1 cm deep emerged and grew well; seeding the plants 10.2 cm deep reduced emergence and growth. Submergence of the soil controlled all weeds effectively but reduced emergence and growth of dry-seeded rice.
Absorption of 2,4,5-T Applied in Various Carriers to Honey Mesquite
Authors: Scifres C. J. , Baur J. R. , Bovey R. W.
Published: May 2019

Absorption of the butyl ether esters of (2,4,5-trichlorophenoxy)-acetic acid (2,4,5-T) by honey mesquite [Prosopis juliflora (Swartz) DC. var. glandulosa (Torr.) Cockerell] foliage was more rapid when 0.56 kg/ha was applied in 15 L/ha paraffin oil than when diesel oil, water, or emulsions of the oils in water were used as carriers. However, carrier had little effect on 2,4,5-T translocation to stems or roots. The percentage of greenhouse-grown honey mesquite plants killed was reduced when 2,4,5-T was applied in diesel oil as compared to other carriers studied.
Broadcast or Banded Atrazine plus Propachlor with Tillage Variables in Corn
Authors: Moomaw R. S. , Robison L. R.
Published: May 2019

The herbicide mixture 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine (atrazine) + 2-chloro-N-isopropylacetanilide (propachlor) was applied preemergence broadcast and in band widths of 18, 36, and 53-cm to corn (Zea maysL.). All herbicide treatments were applied as 1.1 kg of atrazine + 2.7 kg of propachlor per treated hectare. One row-middle cultivation and one rotary hoeing were also imposed on the herbicide treatments as variables. The 18-cm band of atrazine + propachlor with supplementary cultivation was as effective in controlling weed growth and maintaining corn yield as were wider herbicide bands or a broadcast treatment. Broadcast treated corn without row-middle cultivation produced significantly less grain than the handweeded check both years of the experiment. The average ratio of weed dry weight to reduction in corn yield was 0.8 to 1. Cultivation of row middles reduced average end-of-season weed yields 80%. Cultivator effectiveness on an 18-cm herbicide band equalled that measured on wider herbicide bands. Rotary hoeing reduced early season weed yields 82 and 38% in 1970 and 1971, respectively.
Control of Kochia in Sugarbeets with 3′-Hydroxypropionanilide Isopropylcarbamate
Authors: Schweizer E. E.
Published: May 2019

When the mixture of 3.4 kg/ha ofS-ethylN-ethylthiocyclohexanecarbamate (cycloate) plus 1.1 kg/ha of 3′-hydroxypropionanilide isopropylcarbamate (R 11913) was applied to three soils before planting sugarbeets (Beta vulgarisL.), the average stand of kochia (Kochia scoparia(L.) Schrad.) was reduced by 89% as compared to 9% with the standard rate of 4.5 kg/ha of cycloate. The competition of foxtail millet (Setaria italica(L.) Beauv.), redroot pigweed (Amaranthus retroflexusL.), and kochia was nearly eliminated throughout the growing season by a combination of 3.4 kg/ha of cycloate plus 1.1 kg/ha of R 11913 applied preplanting and 0.84 kg/ha of methylm-hydroxycarbanilatem-methylcarbanilate (phenmedipham) applied postemergence. This combination of treatments minimized competition from weeds all season, and the yield of sucrose was within 8% of that of the handweeded plots. Residues of the mixture of cycloate plus R 11913 were not detected biologically in two soils 8 months following application.
Common Chickweed Control in Established Alfalfa
Authors: Kapusta George
Published: May 2019

Herbicide treatments were applied to established alfalfa (Medicago sativaL.) in 1969 and 1970 to determine winter annual weed control efficacy, crop tolerance, and influence on alfalfa yield and protein. Common chickweed (Stellaria media(L.) Cyrillo) was the predominant species in both years. Excellent weed control was achieved in 1969 with 2-sec-butylamino-4-ethylamino-6-methoxy-s-triazine (GS 14254) at 1.7 kg/ha, 2-[[4-chloro-6-(ethylamino)-s-triazin-2-yl]amino]-2-methyl-propionitrile (cyanazine) at 4.5 kg/ha, 2-chloro-4,6-bis(ethylamino)-s-triazine (simazine) at 1.7 kg/ha, and 3-tert-butyl-5-chloro-6-methyluracil (terbacil) at 1.1 kg/ha. Several other treatments also significantly reduced weed yields. All herbicides significantly reduced weed yields in 1970. First harvest alfalfa yields in 1969 were not increased significantly despite the excellent weed control afforded by several treatments. Second harvest alfalfa yields did not differ significantly, however, weeds were not a problem in the regrowth. In 1970 four of the 19 treatments did yield significantly more than control plots. Alfalfa protein was not altered by any of the treatments either year.
Yellow Nutsedge Control with MBR-8251
Authors: Gentner W. A.
Published: May 2019

Equimolar concentrations of 4-phenylsulfonyltrifluoromethanesulfono-o-toluidide (hereafter referred to as MBR-8251),S-ethyl dipropylthiocarbamate (EPTC), and 2-chloro-2′,6′-diethyl-N-(methoxymethyl)acetanilide (alachlor) were compared using a quartz gravel nutrient culture method for detecting toxicity to yellow nutsedge (Cyperus esculentusL.), okra (Hibiscus esculentusL.), cabbage (Brassica oleraciavar.captataL.), cucumber (Cucumis sativusL.), and flax (Linum ustitatissimumL.). MBR-8251 was more active on yellow nutsedge than EPTC or alachlor, and MBR-8251 treated nutlets were controlled for a longer period. In general, crops were more tolerant of MBR-8251. Field studies comparing the effectiveness of MBR-8251 to EPTC,S-propyl dipropylthiocarbamate (vernolate), 2-chloro-4-(ethylamino)-6-isopropylamino-s-triazine (atrazine), 3-isopropyl-2,1,3-benzothiazinone-(4)-2,2-dioxide-6,7,8 (BAS-3510), alachlor, and 2-chloro-N-(ethoxymethyl)-6′-ethyl-o-acetotoluidide (MON-097) indicated that after 10 weeks yellow nutsedge control was excellent with MBR-8251, MON-097, and alachlor.
Tolerance of Two Sugarcane Cultivars to Terbacil, Fenac, and Dalapon
Authors: Matherne R. J. , Millhollon R. W.
Published: May 2019

Two Louisiana sugarcane cultivars (interspecific hybrids of the genusSaccharum) CP 52–68 and L 60-25 were sprayed with herbicides commonly used for preemergence and postemergence control of johnsongrass (Sorghum halepense(L.) Pers.) and other weeds. The preemergence weed control treatments of 3-tert-butyl-5-chloro-6-methyluracil (terbacil) at 1.8 kg/ha and (2,3,6-trichlorophenyl)acetic acid (fenac) at 5 kg/ha were compared to a mixture of sodium salt of trichloroacetic acid (TCA) at 11 or 19 kg/ha plus 2-(2,4,5-trichlorophenoxy)propionic acid (silvex) at 3.4 kg/ha (control). Herbicides were applied after planting in the fall, reapplied the following spring (after sugarcane emerged), and applied again in the second spring on the stubble crop (after sugarcane emerged). In the stubble crop the sodium salt of 2,2-dichloropropionic acid (dalapon) at 0, 5, or 10 kg/ha was applied as a postemergence spray over the top of sugarcane. In the factorial arrangement each cultivar received all combinations of the preemergence x postemergence treatments.

Terbacil did not injure either cultivar, but fenac injured both enough to reduce the yield of sugar in plant cane by about 10% as compared to the TCA plus silvex control. Stubble crop yields were not affected by fenac or terbacil. CP 52–68 was more tolerant to dalapon treatments than L 60–25. Both cultivars tolerated dalapon at 5 kg/ha relatively well although the yield of L 60–25 was reduced by about 5%. However at 10 kg/ha, dalapon reduced yields of CP 52–68 and L 60–25 by about 10 and 18%, respectively. Combinations of preemergence and postemergence treatments did not interact to reduce yields more than the combined effects of each treatment.
Studies on Evapotranspiration of Some Aquatic Weeds
Authors: Brezny Oto , Mehta Indu , Sharma Ram Krishna
Published: May 2019

The evapotranspiration of six dominant emersed and floating weeds was studied. Evapotranspiration of water-chestnut (Trapa natans L. var. bispinosa Roxb.), waterlettuce (Pistia stratiotes L.), and swamp morningglory (Ipomea aquatica Forsk.) did not increase water losses significantly. Evapotranspiration of waterhyacinth (Eichornia crassipes (Mart) Solms.) was 30 to 40% higher, that of narrowleaf cattail (Typha augustifolia L.) was 60 to 70% higher, and that of purple nutsedge (Cyperus rotundus L.) was 130 to 150% higher than evaporation from a free water surface under equivalent conditions. Positive correlations (significant at the 1% level) were found between some meterological factors (daily maximum air temperature and daily average wind velocity), evaporation from free water surface, and evapotranspiration from aquatic plants studied.
Basis for Variability in the Cucumber for Tolerance to Chloramben Methyl Ester
Authors: Miller J. C. , Penner Donald , Baker L. R.
Published: May 2019

The physiological basis for tolerance and susceptibility of four lines of cucumber (Cucumis sativusL.) to the methyl ester of 3-amino-2,5-dichlorobenzoic acid (chloramben) was investigated. ‘MSU 3207’ and ‘MSU 0612’ were tolerant (T), whereas ‘MSU 3159’ and ‘MSU 0866’ were susceptible (S). Intraspecific variability was related to higher concentrations of chloramben in the roots of the susceptible lines, resulting from metabolic differences in these lines and rapid absorption of the herbicide by the roots of ‘S-MSU 3159’. Tolerance of ‘T-MSU 3207’ resulted primarily from low uptake and reduced translocation of the herbicide, while tolerance of ‘T-MSU 0612’ was related to, but not necessarily explained by, a peculiar14C-label distribution pattern in the leaves. Thin-layer chromatographic analysis of methanol-soluble extracts from the lines studied 3 days after14C-chloramben methyl ester treatment separated six14C-metabolites in the roots and five in the shoots. After a 4-hr treatment,14C-chloramben methyl ester was absorbed and translocated more rapidly than14C-chloramben by all four lines. Tolerance or susceptibility did not always correlate with the total concentration of radioactivity in methanol-soluble shoot and root extracts.
Wheat Tolerance to TCA for Green Foxtail Control
Authors: Chow P. N. P. , Dryden R. D.
Published: May 2019

Seven cultivars of spring wheat (Triticum aestivum L.) and one hybrid (Triticale hexaploid Lart. ‘Rosner’) were evaluated in seven field experiments and one greenhouse test for tolerance to the postemergence application of the sodium salt of trichloroacetic acid (TCA) for the control of green foxtail (Setaria viridis (L.) Beauv.). The control of green foxtail and broadleaf weeds was also studied. Of the seven cultivars, ‘Pitic 62’ and ‘Stewart’ were most susceptible to injury from TCA. All other cultivars were tolerant to 0.56 kg/ha. ‘Selkirk’ appeared to be most resistant. With ‘Manitou’ 0.56 kg/ha of TCA gave about 50% control of green foxtail. Higher rates permitted increased growth of broadleaf weeds as a result of reduced competition from injured wheat and green foxtail. Control of all weeds was improved by 10 to 30% when TCA was applied with one of the phenoxy herbicides. Satisfactory crop tolerance and good weed control was achieved with 0.56 kg/ha TCA and 0.56 kg/ha of the amine salt of (2,4-dichlorophenoxy)acetic acid (2,4-D).
Chemical Weed Control in Tall Bearded Iris
Authors: Milbocker D. C.
Published: May 2019

Fall-applied 2-chloro-4,6-bis(ethylamino)-s-triazine (simazine) and α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin) satisfactorily controlled annual and biennial weeds in tall bearded iris (Iris germanica L.). Increased application rates improved control of semitolerant weeds. Trifluralin controlled grass weeds better than simazine. Simazine caused leaf tip and root necrosis, and trifluralin prevented root growth of iris plants when incorporated in the root zone at high rates of application.
Proso Millet Date of Planting and Tolerance to Atrazine
Authors: Robinson R. G.
Published: May 2019

Proso millet (Panicum miliaceumL. ‘Turghai’, ‘M28’, and ‘Panhandle’) was planted at three or four dates from late April to late June in 1970, 1971, and 1972 on silt loam soil and in 1972 on sandy soil. A single spray application of 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine (atrazine) at 2.24 kg/ha on half of each date plot was preemergence to the first date and preplanting to the last two or three dates of planting. Proso millet was not injured by atrazine. At each date, weed control was better on sprayed than on untreated plots. Foxtails (Setariaspp.) were the only weeds present after all plots on silt loam soil were sprayed postemergence with (2,4 dichlorophenoxy)acetic acid (2,4-D). Millet planted early produced higher yields than millet sown at normal planting dates if foxtail competition was not serious. Use of selective herbicides and spring planting offer a potential major gain in the profitability of millet production in areas where annual weed problems now relegate millet to summer planting.
Anatomy and Sprouting of Yellow Nutsedge Tubers
Authors: Bendixen Leo E.
Published: May 2019

Buds of locally collected yellow nutsedge (Cyperus esculentusL.) tubers are formed only at the six most apical nodes with a 1/3 phyllotaxy. The oldest bud is largest. Bud size grades to the small apical bud. Veins of the rhizome are continuous through the tuber to each bud, root, and leaf. Buds break dormancy in acropetal order, starting with the oldest bud. If the tubers and buds remain undisturbed, usually only two buds break dormancy and grow into shoots.
Field Comparison of Twelve Dinitroaniline Herbicides
Authors: Harvey R. G.
Published: May 2019

The effects of twelve substituted dinitroaniline herbicides on soybeans [Glycine max(L.) Merr., ‘Corsoy’], velvetleaf (Abutilon theophrastiMedic.), and giant foxtail (Setaria faberiHerrm.) were evaluated under field conditions in 1971 and 1972; and the relative persistence of herbicide residues in soil was determined by field bioassay. Of the herbicides tested, dinitramine (N4,N4-diethyl-α,α,α-trifluoro-3,5-dinitrotoluene-2,4-diamine), trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine), and benefin (N-butyl-N-ethyl-α,α,α-trifluoro-2, 6-dinitro-p-toluidine) reduced soybean stands in 1971. Only dinitramine reduced soybean stands in 1972 when applied in low rates, but all of the herbicides except CGA-10832 (N,N-propyl-N-cyclopropylmethyl-4-trifluoromethyl-2,6-dinitroaniline) and chlornidine [N,N(2-chloroethyl)-2,6-dinitro-4-methylaniline] reduced soybean stands at high rates. Overall, oryzalin (3,5-dinitro-N4,N4-dipropylsulfanilamide), dinitramine, and BAS-3921 H[N-propyl-N-(2-chloroethyl)-2,6-dinitro-4-trifluoromethylaniline] provided the best velvetleaf control; while trifluralin, benefin, CGA-10832, and BAS-3921 H produced the most satisfactory giant foxtail control. In 1972, residues of seven of the herbicides caused injury to oats planted over the plot area 355 days after the original herbicide application. The greatest oat injury was caused by trifluralin and oryzalin. Oats were not injured, however, from dinitramine residues when planted only 75 days after the herbicide application.
Influence of Weeds on Soybean Harvesting Losses with a Combine
Authors: Burnside O. C.
Published: May 2019

Various soybean [Glycine max(L.) Merr. ‘Amsoy’] losses during harvesting with a combine were studied in relation to different weed densities, weed species, and growing weeds (early harvest) versus desiccated weeds (late harvest). Average soybean losses from shattering and stubble, stalk, and threshing losses were 7.8, 0.9, 2.0, and 1.4% of total yields, respectively. All harvest losses except threshing losses were significantly greater on late as compared with early harvested soybeans. The major loss from weeds in soybeans was reduced yields due to competition; whereas, harvesting losses were associated with high soybean yields and low weed yields. Soybean harvesting losses were 19% greater on plots containing a predominance of broadleaf compared with grass weeds. Average harvesting losses of 12.1% of total soybean yields ranged with treatments from 8.8 to 15.5%. Average gathering losses were 10.7% and threshing losses 1.4% of total soybean yields.
Arsenic Phytotoxicity and Uptake in Six Vegetable Crops
Authors: Woolson E. A.
Published: May 2019

Six vegetable crops were greenhouse-grown to maturity in three Maryland soils treated with up to 500 ppm of arsenic (As) added as sodium arsenate. Phytotoxicity of arsenic residues was highest on Lakeland loamy sand and lowest on Hagerstown silty clay loam. Correlations between available arsenic and plant dry weight indicated that crop sensitivity proceeded as follows: green beans (Phaseolus vulgaris L. ‘stringless greenpod’) > lima beans (Phaseolus linensis L. ‘Fordhook 242’) spinach (Spinacia oleracea L. ‘Longstanding Bloomsdale Savoy’) > radish (Raphanus sativus L. ‘Champion’) > tomato (Lycopersicon esculentum Mill. ‘F-7’) > cabbage (Brassica oleracea L. var. capitata L. ‘Jersey Wakefield’). Residues in the total dry plant at the available arsenic level at which growth was reduced 50% (GR50) were highest with radish (43.8 ppm) and spinach (10.0 ppm). Residues in the dry-edible portion increased to 76.0 ppm arsenic for unpeeled, washed radish at the GR50 point. The soil at the GR50 level for radish contained about 19 ppm of available arsenic from a 50 ppm arsenate treatment to Lakeland loamy sand and a 100 ppm treatment to Hagerstown silty clay loam and to Christiana clay loam.
Measurement and Prediction of Picloram Disappearance Rates from Soil
Authors: Meikle R. W. , Youngson C. R. , Hedlund R. T. , Goring C. A. I. , Hamaker J. W. , Addington W. W.
Published: May 2019

We have shown by means of laboratory experiments with a wide range of soil types that the decomposition rate of picloram (4-amino-3,5,6-trichloropicolinic acid) in soil is dependent on soil temperature and moisture content and to no significant extent on organic matter, sand, silt, clay, pH, or initial concentration. A fractional order rate law (0.8) describes the disappearance rate best. It was not possible to develop a suitably precise equation for prediction of loss rate as affected by the above soil and climatic factors. Application of the Arrhenius equation to the data indicates an activation energy of 5.4 kcal/mol for the decomposition of picloram in soil, thus suggesting that the reaction is biological rather than chemical.
Direct Liquid Scintillation Radioassay of14C-Labeled Herbicides in Soil
Authors: Lavy T. L. , Messersmith C. G. , Knoche H. W.
Published: May 2019

A liquid scintillation counting solution was developed which optimized the direct assay efficiencies of14C-labeled 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine (atrazine), 3,6-dichloro-o-anisic acid (dicamba), and α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin) in soil. In this counting technique, 3-g soil samples containing14C-labeled herbicide were placed directly into a liquid scintillation vial containing a phosphorescent counting solution. Samples were shaken and allowed to settle before assaying using a liquid scintillation spectrometer. This direct radioassay was as efficient or more efficient than double or single extraction processes. Automatic external standardization in conjunction with the liquid scintillation counter was an effective tool for estimating the14C present in soil samples.
Control of Yaupon and Associated Species
Authors: Bovey R. W. , Morton H. L. , Meyer R. E. , Flynt T. O. , Riley T. E.
Published: May 2019

Early spring spray applications of the potassium salt of 4-amino-3,5,6-trichloropicolinic acid (picloram) and certain formulations of 1:1 mixtures of picloram plus (2,4,5-trichlorophenoxy)acetic acid (2,4,5-T) controlled yaupon(Ilex vomitoriaAit.). Ester formulations of picloram or picloram plus 2,4,5-T were ineffective. Combinations of surfactant and oil: water carriers usually did not improve herbicide performance over water carriers. Granular picloram was superior to sprays when applied as soil treatments at equal rates and controlled yaupon at most dates of application. Post oak(Quercus stellataWangenh.) and blackjack oak(Quercus marilandicaMuenchh.) were controlled more effectively by picloram or picloram plus 2,4,5-T sprays on the foliage than by granular picloram as a soil treatment. Picloram granules usually killed winged elm(Ulmus alataMichx.) regardless of date of application.
Growth Regulator-Like Activity of Atrazine and Ametryne
Authors: Copping Leonard G. , Davis D. E. , Pillai C. G. P.
Published: May 2019

Atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] and 2-(ethylamino)-4-(isopropylamino)-6-(methylthio)-s-triazine (ametryne) were tested for growth regulatorlike effects. In the presence of 10 μg/ml of kinetin, atrazine had no effect on the growth of callus tissue of soybean (Glycine max Merr. ‘Lee’), but ametryne at 10−14M concentration stimulated callus growth and the production of roots. High concentrations of both atrazine and ametryne inhibited the growth of excised roots of tomato (Lycopersicon esculentum Miller ‘Atkinson’). Ametryne, and to a lesser extent atrazine, increased percent germination of seed of lettuce (Lactuca sativa L. ‘Grand Rapids’) and tobacco (Nicotiana tobaccum L. ‘Sansum’) exposed to only 4 min of red light. Both atrazine and ametryne stimulated adventitious root formation by excised hypocotyls of mung beans (Phaseolus aureus Roxb.) in the absence of 10 ppm of exogenous indoleacetic acid (IAA) but not in its presence. A high concentration of atrazine (10−6M) in the presence of IAA decreased root initiation in comparison with the IAA-treated controls.
Lipid Contribution to Selective Action of Trifluralin
Authors: Hilton J. L. , Christiansen M. N.
Published: May 2019

Preplanting treatment of filter paper or soil containing α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin) with any of a wide variety of plant lipids prevented the phytotoxic action of the herbicide in laboratory situations. The protective action of externally applied lipids was attributed to preventing sorption of trifluralin by seedlings. However, protection by internal lipids also appeared likely. A significant correlation (1% level) was demonstrated between seedling sensitivity to trifluralin and the lipid content of dry seeds of 11 weed and crop species. Artificially induced increases in the internal lipid content of wheat(Triticum aestivumL. ‘Mediterranean’) seed resulted in greater tolerance of seedlings to trifluralin. Therefore, it is hypothesized that selective phytotoxicity of trifluralin to young seedlings is determined in part by the amount of endogenous lipids available to trap trifluralin and keep it from its site of phytotoxic action. Tolerance above that predicted from seed lipid content was observed in a twelfth species of the study.
Effect of DMSO and Surfactant Combinations on Tissue Concentrations of Picloram
Authors: Baur J. R. , Bovey R. W. , Smith J. D.
Published: May 2019

Over a 2-year period no treatment differences were noted in 4-amino-3,5,6-trichloropicolinic acid (picloram) concentrations recovered from grass and yaupon(Ilex vomitoriaAit.) tissues treated with 1.12 kg/ha of picloram in mixture with dimethyl sulfoxide (DMSO) and surfactant (X-77).4Less than 1 μg of picloram per gram of fresh weight of grass or yaupon was present in aerial tissue 6 months after treatment, in yaupon stem tissues 1 month after treatment, and in yaupon root tissue 5 days after treatment. Tissues sampled 1 year after treatment were devoid of picloram residue; tissues sampled 1 year after retreatment had levels ranging from 0.04 to 0.26 μg/g. The April application of 1.12 kg/ha of picloram plus 5.0% X-77 plus 10.0 or 25.0% of DMSO produced more effective canopy reduction of yaupon 1 year after treatment than did other herbicide treatments or dates of treatment. Increased canopy reduction by retreatment the second year suggests that X-77 rather than DMSO was the effective component in the spray mixtures.
Enzymatic Hydrolysis of Herbicides in Plants
Authors: Hoagland R. E. , Graf G.
Published: May 2019

Nineteen different genera of weeds encompassing twelve plant families were surveyed for hydrolytic enzymes which were able to metabolize the amide bonds in several groups of herbicides. Propanil (3′,4′-dichloropropionanilide), 1,1-dimethyl-3-phenylurea (fenuron), and isopropyl carbanilate (propham) were employed as enzyme substrates, representing the amide, urea, and carbamate classes. Propanil was hydrolyzed at widely diverse rates by approximately 70% of the plants tested. Only one plant showed a hydrolysis of propham and fenuron. The study demonstrates a widespread distribution of hydrolytic enzymes capable of degrading the herbicide, propanil. An apparent lack of hydrolytic enzymes able to metabolize propham and fenuron was also noted.
Concentration of Picloram in the Soil Profile
Authors: Baur J. R. , Baker R. D. , Bovey R. W. , Smith J. D.
Published: May 2019

Soil residue levels were studied to a depth of 2.4 m for a period of 2 years after application of 1.12 kg/ha of 4-amino-3,5,6-trichloropicolinic acid (picloram). Thirty days after application 93 ppb were recovered in the top 15 cm of soil. Residues were less than 5 ppb at depths of 46 to 122 cm. Six months after application, residues were between 5 and 10 ppb down to 183 cm and less than 5 ppb between 198 and 244 cm. Residues to depths of 244 cm were less than 5 ppb 1 year after treatment. Residue levels to similar depths were studied in two soil types for a period of 1 year after application of conventional and polymerized picloram sprays and granules (3.4 kg/ha of picloram). Conventional sprays resulted in significantly higher soil residues for the sampling period than polymerized sprays. Residues from polymer granules were likewise significantly greater than from polymer sprays. Conventional and polymer formulations were identical with respect to movement through the soil.
Concentration of Picloram in Runoff Water
Authors: Baur J. R. , Bovey R. W. , Merkle M. G.
Published: May 2019

Runoff water was sampled over a 2-year period from an 8-ha site that had been treated and retreated with 4-amino-3,5,6-trichloropicolinic acid (picloram) at the rate of 1.12 kg/ha in the spring of 1969 and 1970. Runoff water was sampled adjacent to the plots and in two creek systems up to 2.0 km from the plots. Samples taken adjacent to the plots declined to less than 10 ppb by 10 to 12 weeks after application. Eight days after application, water sampled 1.2 km from the plots contained less than 1 ppb of picloram. Less than 1.0 ppb levels were occasionally detected 1.6 km from the plots 8 months after treatment.
Droplet and Vapor Drift from Butyl Ester and Dimethylamine Salt of 2,4-D
Authors: Grover R. , Maybank J. , Yoshida K.
Published: May 2019

The relative drift of droplet and vapor of butyl ester and dimethylamine formulations of (2,4-dichlorophenoxy)acetic acid (2,4-D) was determined under conventional crop spraying procedures in the field. Labelled herbicides were mixed with spray solution or emulsion, and the ground deposit and the air-borne droplet and vapor clouds drifting from the target area were collected. The mass of the dimethylamine formulation drifting as droplets was 3 to 4% of the material sprayed. No significant amounts of this material were collected as vapor or particulate drift. For the butyl ester, in addition to the droplet drift, 25 to 30% of the material was collected as vapor drift in the half hour after spraying. Thus the drift potential from the butyl ester was about 8 to 10 times greater than that from the dimethylamine formulation under the conditions of these tests.
Effect of 2,4-DB on White Clover Seed Production
Authors: Lee William O.
Published: May 2019

Seed fields of white clover (Trifolium repens L. ‘New Zealand’ and ‘Louisiana S-1′) were treated with the dimethylamine salt and the isooctyl ester of 4-(2,4-dichlorophenoxy)-butyric acid (2,4-DB). Rates of application were 0.56, 1.12, and 1.68 kg/ha. Applications were made at the vegetative, bud, and flowering stages of growth. All treatments applied at the vegetative and bud stages of growth significantly reduced white clover seed production. Reductions in clover seed production usually became more severe as the rate of 2,4-DB increased.
A Proposed Mechanism for Diuron-Induced Phytotoxicity
Authors: Stanger Charles E. , Appleby Arnold P.
Published: May 2019

Chloroplasts isolated from spinach(Spinacia oleraceaL.) leaves were used to study mechanisms of toxicity from 3-(3,4-dichlorophenyl)-1,1-dimethylurea (diuron). Light was needed to initiate diuron injury. The addition of ascorbate plus 2,6-dichlorophenylindolephenol (DPIP) as an electron donor system completely protected the chloroplasts from diuron-induced toxicity. The protective effect from the electron donor system occurred only in functional chloroplasts. Diuron caused rapid and extensive chlorophyll degradation at chlorophyll: diuron ratios of 200:1 and lower. At higher ratios the effect was much less measurable. The electron donor system gave complete protection in the presence of methylamine HCl, a known inhibitor of photophosphorylation, indicating that a deficiency of ATP was not the primary cause of diuron toxicity. Time-course studies showed that carotenoid pigments began to degrade before initiation of chlorophyll degradation. These results are interpreted as supporting a hypothesis that diuron induces phytotoxicity by catalyzing lethal photosensitized oxidations in the cell. This may occur as a result of (a) a greater concentration of oxidized chlorophyll caused by an interruption of electron flow and (b) an inhibition of NADPH formation which is necessary to maintain a functional carotenoid protective mechanism.
Competition of Sicklepod with Soybeans
Authors: Thurlow Donald L. , Buchanan Gale A.
Published: May 2019

The competitive effects of sicklepod(Cassia obtusifoliaL.) on soybeans(Glycine maxL. ‘Bragg’) were studied on Malbis sandy loam soil and Chesterfield sandy loam soil during 1968 to 1970. Weed density was a linear function of soybean yield for the densities studied (0 to 15 weeds/m2). The regression coefficient of weed density (weeds per square meter) on bean yield (kilograms per hectare) was −92 and −101 for the two soils, respectively. When the data were combined across both soils and years, the regression coefficient was −95. Densities of 7.7 weeds/m2reduced soybean yield 19 to 32% and 34 to 35% on the two soils, respectively. The weight of weeds at harvest was also inversely correlated to soybean yield. Sicklepod was more competitive when grown 15 to 30 cm from the drill than in the drill. Soybean yields were reduced in some instances when sicklepod was allowed to compete for as little as 4 weeks. If weeds were removed at 2 to 4 weeks after soybean emergence, no further weed removal was needed for maximum yield of soybeans.
Seasonal Development of Established Johnsongrass
Authors: Horowitz Menashe
Published: May 2019

Growth of tops and rhizomes of established johnsongrass(Sorghum halepense(L.) Pers.) stopped almost completely in the cool winter season. Rhizome growth started in spring later than topgrowth. Rhizomes constituted more than 90% of the total subterranean weight. In a sward of pure johnsongrass, 60%, 30%, and 10% of the total subterranean weight were found in the 0 to 15-cm, 15 to 30-cm, and 30 to 45-cm soil layer, respectively. Water-soluble sugar content in rhizomes was high in early winter and in early summer and low in early spring and in fall. Less water-soluble sugars were found in shallow than in deeper rhizomes. In winter the sugars accumulated mainly in the deepest rhizomes. No clear relation was detected between the sprouting percentage of rhizome buds and growth, sugar content, or seasonal climatic factors. No case of complete sprouting inhibition was recorded during the year.
Effects of Continued use of Herbicides in Asparagus Plantings
Authors: Welker William V. , Brogdon Jennie L.
Published: May 2019

The effects of repeated annual applications of nine herbicides on a planting of asparagus (Asparagus officinalis L. ‘Martha Washington’) were studied over a 7-year period. Weed competition during the cutting season seriously reduced yields. Large populations of common lambsquarters (Chenopodium album L.) developed where 3-amino-2,5-dichlorobenzoic acid (chloramben) and N,N-dimethyl-2,2-diphenylacetamide (diphenamid) were used. Large increases in redroot pigweed (Amaranthus retroflexus L.) occurred where dimethyl tetrachloroterephthalate (DCPA) was used. The fiber content of asparagus treated with 3-(p-chlorophenyl)-1,1-dimethylurea (monuron) and 3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea (linuron) increased during slow growing conditions. Spear emergence in the spring was delayed when 2,6-dichlorobenzonitrile (dichlobenil) was applied near bud break. There was no indication that continuous use of any of the herbicides studied resulted in a buildup in the soil or plants causing a deleterious effect upon the yield of asparagus.