bluuebunny/crossref_metadata_2025 huggingface dataset:
Clustering of rapidly settling, low-inertia particle pairs in isotropic turbulence. Part 1. Drift and diffusion flux closures
Authors: Rani Sarma L. , Gupta Vijay K. , Koch Donald L.
Published: May 2019

In this two-part study, we present the development and analysis of a stochastic theory for characterizing the relative positions of monodisperse, low-inertia particle pairs that are settling rapidly in homogeneous isotropic turbulence. In the limits of small Stokes number and Froude number such that $Fr\ll St_{\unicode[STIX]{x1D702}}\ll 1$, closures are developed for the drift and diffusion fluxes in the probability density function (p.d.f.) equation for the pair relative positions. The theory focuses on the relative motion of particle pairs in the dissipation regime of turbulence, i.e. for pair separations smaller than the Kolmogorov length scale. In this regime, the theory approximates the fluid velocity field in a reference frame following the primary particle as locally linear. In this part 1 paper, we present the derivation of closure approximations for the drift and diffusion fluxes in the p.d.f. equation for pair relative positions $\boldsymbol{r}$. The drift flux contains the time integral of the third and fourth moments of the ‘seen’ fluid velocity gradients along the trajectories of primary particles. These moments may be analytically resolved by making approximations regarding the ‘seen’ velocity gradient. Accordingly, two closure forms are derived specifically for the drift flux. The first invokes the assumption that the fluid velocity gradient along particle trajectories has a Gaussian distribution. In the second drift closure, we account for the correlation time scales of dissipation rate and enstrophy by decomposing the velocity gradient into the strain-rate and rotation-rate tensors scaled by the turbulent dissipation rate and enstrophy, respectively. An analytical solution to the p.d.f. $\langle P\rangle (r,\unicode[STIX]{x1D703})$ is then derived, where $\unicode[STIX]{x1D703}$ is the spherical polar angle. It is seen that the p.d.f. has a power-law dependence on separation $r$ of the form $\langle P\rangle (r,\unicode[STIX]{x1D703})\sim r^{\unicode[STIX]{x1D6FD}}$ with $\unicode[STIX]{x1D6FD}\sim St_{\unicode[STIX]{x1D702}}^{2}$ and $\unicode[STIX]{x1D6FD}<0$, analogous to that for the radial distribution function of non-settling pairs. An explicit expression is derived for $\unicode[STIX]{x1D6FD}$ in terms of the drift and diffusion closures. The $\langle P\rangle (r,\unicode[STIX]{x1D703})$ solution also shows that, for a given $r$, the clustering of $St_{\unicode[STIX]{x1D702}}\ll 1$ particles is only weakly anisotropic, which is in conformity with prior observations from direct numerical simulations of isotropic turbulence containing settling particles.
Interannual climate variability helps define the mean state of glaciers
Authors: MALONE ANDREW G.O. , DOUGHTY ALICE M. , MACAYEAL DOUGLAS R.
Published: May 2019

Changes in glacier length and extent are indicators of contemporary and archives of past climate changes, but this common climate proxy presents a challenge for inferring a climate signal. Modeling studies suggest that length fluctuations can occur due to interannual climate variability within an unchanging mean climate and that changes in interannual climate variability can also drive changes in average length. This paper quantifies the impacts of interannual climate variability on average glacier length and mass balance, using a flowline model coupled to a simplified mass-balance model. Results illustrate that changes in the magnitude of interannual temperature variability can non-linearly affect the mean glacier length through a mass-balance asymmetry between warm and cold years. This asymmetry is present in models where melt only initiates after a temperature threshold is crossed. Glaciers susceptible to this asymmetry can be identified based on the shape of their mass-balance profiles. The presence of mass-balance asymmetries in glaciological databases is evaluated, but current records are too short for high statistical resolving power. While the asymmetry in this study can affect the average length and mass-balance, its impacts are small, and paleoclimate interpretations from glacier-length changes are likely not notably influenced by this process.
The seeds of supermassive black holes and the role of local radiation and metal spreading
Authors: Maio Umberto , Borgani Stefano , Ciardi Benedetta , Petkova Margarita
Published: May 2019

We present cosmological hydrodynamical simulations including atomic and molecular non-equilibrium chemistry, multi-frequency radiative transfer (0.7–100 eV sampled over 150 frequency bins) and stellar population evolution to investigate the host candidates of the seeds of supermassive black holes coming from direct collapse of gas in primordial haloes direct-collapse black holes, DCBHs. We consistently address the role played by atomic and molecular cooling, stellar radiation and metal spreading of C, N, O, Ne, Mg, Si, S, Ca, Fe, etc. from primordial sources, as well as their implications for nearby quiescent proto-galaxies under different assumptions for early source emissivity, initial mass function, and metal yields. We find that putative DCBH (direct-collapse black holes) host candidates need powerful primordial stellar generations, since common solar-like stars and hot OB-type stars are neither able to determine the conditions for direct collapse nor capable of building up a dissociating Lyman–Werner background radiation field. Thermal and molecular features of the identified DCBH host candidates in the scenario with very massive primordial stars seem favourable, with illuminating Lyman–Werner intensities featuring values of 1 – 50J21. Nevertheless, additional nonlinear processes, such as merger events, substructure formation, rotational motions, and photo-evaporation, should inhibit pure direct-collapse black hole formation in two-third of the cases. Local turbulence may delay gas direct collapse almost irrespectively from other environmental conditions. The impact of large Lyman–Werner fluxes at distances smaller than ~5 kpc is severely limited by metal pollution.
Overruling Precedent
Authors: Barak Aharon
Published: May 2019

The legal scholarship of Prof. G. Tedeschi is broad and comprehensive, encompassing all areas of the civil law and reaching into the public law as well. At its base, there lies a solid jurisprudential foundation, in the context of which Prof. Tedeschi has devoted considerable thought to the various issues of the theory of precedent. In gratitude to Prof. Tedeschi, my venerable teacher and dear friend, to whom I owe the greatest of debts, and who for me serves as both model and symbol, I would take this opportunity to consider one aspect of the doctrine of precedent – that of overruling precedent.
International Criminal Law
Authors: Dinstein Yoram
Published: May 2019

The individual human being is manifestly the object of every legal system on this planet, and consequently also of international law. The ordinary subject of international law is the international corporate entity: first and foremost (though not exclusively) the State. Yet, the corporate entity is not a tangible res that exists in reality, but an abstract notion, moulded through legal manipulation by and within the ambit of a superior legal system. When the veil is pierced, one can see that behind the legal personality of the State (or any other international corporate entity) there are natural persons: flesh-and-blood human beings. In the final analysis, Westlake was indubitably right when he stated:

The duties and rights of States are only the duties and rights of the men who compose them.

That is to say, in actuality, the international rights and duties of States devolve on human beings, albeit indirectly and collectively. In other words, the individual human being is not merely the object of international law, but indirectly also its subject, notwithstanding the fact that, ostensibly, the subject is the international corporate entity.
Association between feed sorting and the prevalence of metabolic disorders in Hungarian large-scale dairy herds
Authors: Jurkovich Viktor , Könyves László , Bakony Mikolt
Published: May 2019

This research communication describes the possible association between feed sorting and the risk of metabolic disorders in dairy cows. Feed sorting, that is selecting smaller size TMR particles over longer length fibers, can lead to imbalanced energy input. In addition, sorting can lead to lower nutritive value of leftover TMR. To detect a possible relationship between TMR sorting and the occurrence of metabolic disorders in large-scale herds, TMR separation and metabolic profile tests were performed in 22 Hungarian dairies. Feed sorting was defined as >5% alteration in the mass proportion of any of the TMR fractions between the time of feed distribution and 5–6 h later. The prevalence of ketosis and subclinical acidosis differed between feed sorting and non-sorting groups. Inhomogeneous TMR seems to be a predisposing factor for imbalanced energy status. TMR homogeneity measurements should be routinely included in herd health monitoring.
Late Kinderhookian (Early Mississippian) Ammonoids of the Western United States
Authors: Gordon Mackenzie
Published: May 2019

Ammonoid faunas of late Kinderhookian (Early Mississippian) age, virtually unknown previously in the American West, are described from several localities in New Mexico, Nevada, Utah, Idaho, and Montana. This study is based upon approximately 130 specimens from 33 collections. These specimens are variously assigned to at least 15 species in the following taxa: Protocanites, Imitoceras, Gattendorfia (Gattendorfia), Kazakhstania, Pericyclus (Goniocyclus), Rotopericyclus (Rotopericyclus), and R. (Hammatocyclus). The genus Muensteroceras, once widely regarded as appearing in the Kinderhookian, is unrepresented in these collections.

The western faunas are characterized by the predominance of the pericyclids and relative scarcity of Imitoceras. Midcontinent faunas of the same age are characterized by the predominance of Imitoceras, scarcity of Pericyclus (Goniocyclus), and presence of Prodromites. Ammonoid faunas of early Osagean age differ in the presence of abundant Muensteroceras and rare Pericyclus (Pericyclus) and in the absence of Prodromites and Pericyclus (Goniocyclus).

Most of the late Kinderhookian ammonoids, both in the West and in the Midcontinent, are assignable to the Siphonodella isosticha–Upper S. crenulata Conodont Zone of Sandberg et al. (1978). A few are referable to the Lower Siphonodella crenulata Zone of the same authors. No ammonoids have been described from equivalent beds in Europe which are included in the Siphonodella crenulata Zone of Voges (1960), despite the fact that Voges regarded this conodont zone as equivalent to the ammonoid Zone CuIIa of Schmidt (1925, p. 493). Based upon conodont correlations, the American Pericyclus (Goniocyclus) fauna is middle Tournaisian (Tn2b, c) in age and, with its Midcontinent equivalents, represents a part of the section between the Gattendorfia and the Pericyclus zones of Europe, from which ammonoids are as yet undescribed.

One new subgenus is described in this paper: Pericyclus (Goniocyclus), its type species Goniatites blairi Miller and Gurley, 1896. New species described include Pericyclus (Goniocyclus) cooperi, P. (G.) costulatus, P. (G.) antelopensis, P. (G.) rockymontanus, P. (G.) filaris, P. (G.)? decipiens, Rotopericyclus (Rotopericyclus) pinyonensis, and R. (Hammatocyclus) brazerensis.
Allelopathy of Small Everlasting (Antennaria microphylla): Identification of Constituents Phytotoxic to Leafy Spurge (Euphorbia esula)
Authors: Manners Gary D. , Galitz Donald S.
Published: May 2019

The ether extract of small everlasting (Antennaria microphyllaRydb.) was phytotoxic to lettuce seed root growth and leafy spurge (Euphorbia esulaL. # EPHES) root elongation and cell culture growth. Three phenolic compounds (hydroquinone, arbutin, and caffeic acid) were chromatographically isolated and characterized from the ether extract. Arbutin and caffeic acid were moderately phytotoxic to leafy spurge root growth at 300 ppm (w/v), and hydroquinone was strongly phytotoxic to leafy spurge root growth at 50 ppm (w/v). The observed phytotoxicity of hydroquinone and the high-yield natural occurrence of arbutin, a water soluble, easily hydrolyzed monoglucoside of hydroquinone, in small everlasting is consistent with the participation of these two compounds in the observed allelopathy of small everlasting against leafy spurge.
Wild Oat (Avena fatua) Competition with Spring Wheat: Effects of Nitrogen Fertilization
Authors: Carlson Harry L. , Hill James E.
Published: May 2019

Field experiments were conducted to determine the effect of nitrogen fertilization on competition between wild oat (Avena fatuaL. # AVEFA) and spring wheat (Triticum aestivum‘Anza’). Nitrogen fertilizer treatments were applied over several wild oat-wheat density combinations. Wheat grain yield in wild oat-infested plots generally declined with fertilization while the density of wild oat panicles increased. Apparently, in competition with wheat, wild oat was better able to utilize the added nitrogen and thus gained a competitive advantage over the wheat. The increased competitiveness of wild oat resulted in reduced crop yields. Under the conditions of these experiments, nitrogen fertilization resulted in positive wheat yield response only when the wild oat plant density was below 1.6 percent of the total plant density.
Culture of Hydrilla (Hydrilla verticillata) in Sand Root Media Amended with Three Fertilizers
Authors: Sutton David L.
Published: May 2019

Hydrilla [Hydrilla verticillata(L.f.) Royle # HYLLI] was grown for 4 to 16 weeks in pans filled with either an organic muck-sand soil, sand, or sand mixed with Osmocote, Esmigran, and dolomite under outdoor conditions in plastic-lined pools with flowing pond water. Dry weight for plants cultured in sand plus the fertilizers was dependent on the concentration of fertilizer and was from 6 to 14 times that of plants cultured in sand alone. Dry weight was also higher for three treatments of sand amended with fertilizer than for plants cultured in the organic muck-sand soil. Water temperature for different growth periods influenced dry weight of hydrilla cultured with all three root media. Tuber production was independent of three levels of fertilizer for 16 weeks of plant growth, but plant weight was dependent on the concentration of nutrients in the root zone. Of nine plant tissue nutrients measured, only phosphorus in both the shoots and roots was dependent on the level of fertilizer in the root zone. This suggests that growth of hydrilla is controlled by nutrients in the root zone. The use of sand amended with various levels of fertilizers may be a way to simulate fertility levels of sediments as a method to study aquatic sites for their potential to support growth of hydrilla.
Kochia scopariaGrowth Response to Triazine Herbicides
Authors: Salhoff Craig R. , Martin Alex R.
Published: May 2019

Greenhouse-grown kochia [Kochia scoparia(L.) Schrad. # KCHSC] seedlings from populations having either a 13-yr triazine history or no triazine history were sprayed postemergence with 0, 2, or 20 kg/ha atrazine [6-chloro-N-ethyl-N′-[1-methylethyl)-1,3,5-triazine-2,4-diamine]. Fresh weight was reduced 20% in triazine history kochia treated with 20 kg/ha atrazine. Seedlings with no triazine history were killed by 2 kg/ha atrazine. Biotypes resistant to atrazine were also resistant to five other triazine herbicides. Biotypes susceptible to atrazine were susceptible to the other triazines. Atrazine-resistant biotypes were more susceptible to 2,4-D [(2,4-dichlorophenoxy)acetic acid] than atrazine-susceptible biotypes, but atrazine history had no effect on response to diuron [N′-(3,4-dichlorophenyl)-N,N-dimethylurea].
Predicting Weed Migration from Soil and Climate Maps
Authors: Chicoine Timothy K. , Fay Peter K. , Nielsen Gerald A.
Published: May 2019

Soil characteristics, elevation, annual precipitation, potential evapotranspiration, length of frost-free season, and mean maximum July temperature were estimated for 116 established infestations of spotted knapweed (Centaurea maculosa Lam. # CENMA) in Montana using basic land resource maps. Areas potentially vulnerable to invasion by the plant were delineated on the basis of representative edaphic and climatic characteristics. No single environmental variable was an effective predictor of sites vulnerable to invasion by spotted knapweed. Only a combination of variables was effective, indicating that the factors that regulate adaptability of this plant are complex. This technique provides a first approximation map of the regions most similar environmentally to infested sites and, therefore, most vulnerable to further invasion. This weed migration prediction technique shows promise for predicting suitable habitats of other invader species.
Influence of pH on the Absorption of Chlorsulfuron by Leaves and Excised Roots of Velvetleaf (Abutilon theophrasti)
Authors: Mersie Wondimagegnehu , Foy Chester L.
Published: May 2019

Chlorsulfuron {2-chloro-N-[[(4-methoxy–6-methyl-1,3,5-triazin-2-yl)amino] carbonyl] benzenesulfonamide} uptake from different pH solutions by leaves and excised root segments of velvetleaf (Abutilon theophrastiMedik. # ABUTH) was examined. In buffer solutions more14C-chlorsulfuron penetrated intact leaves at lower pH levels (2.4, 3.4, and 4.4) than at pH 5.6. Initial chlorsulfuron absorption by 1-cm segments cut from the apical 5 cm of roots was rapid in the first 10 min for all pH levels. During the first 10 min, roots absorbed more chlorsulfuron from acidic (pH 2.4 and 3.4) than from higher pH solutions (pH 4.4 and 5.6). Chlorsulfuron efflux occurred in two phases for all pH levels. The first phase was a rapid loss through approximately 10 min, and the second a slow loss through 240 min. In the first 10 min, the efflux of chlorsulfuron was faster from roots incubated in pH 2.4 than in higher pH solutions. Efflux from the other pH levels was similar.
Influence of Johnsongrass (Sorghum halepense) Density and Period of Competition on Cotton Yield
Authors: Bridges David C. , Chandler James M.
Published: May 2019

Research was conducted from 1982 through 1984 on a Shipps clay soil (Udic chromustert) in east-central Texas to determine the density-dependent effects and critical periods of johnsongrass [Sorghum halepense(L.) Pers. # SORHA] competition with cotton (Gossypium hirsutumL.). Two experiments were conducted each year, one to assess cotton yield response to increasing johnsongrass density and the second to establish the johnsongrass-free requirement of cotton and the johnsongrass competition period. A critical minimum density of 2 plants/9.8 m of row was observed. Full-season johnsongrass competition densities exceeding 2 plants/9.8 m of row resulted in seed cotton yield reductions each year. Yield decline was most rapid as density increased from 2 to 8 plants/9.8 m of row. Yield loss averaged 1, 4, 14, 40, 65, and 70% for johnsongrass densities of 1, 2, 4, 8, 16, and 32 plants/9.8 m of row, respectively. Percent yield loss was proportional to yield potential at johnsongrass densities of 4 and 8 plants/9.8 m of row. Three to four weeks of rhizome johnsongrass competition or 6 weeks of seedling johnsongrass competition resulted in significant yield reductions. Maintaining cotton johnsongrass free for 4 weeks did not prevent significant yield reductions.
Selective Control of Mountain Big Sagebrush (Artemisia tridentatassp.vaseyana) with Clopyralid
Authors: Whisenant Steven G.
Published: May 2019

Sprays of 2.2 kg ae/ha of 2,4-D [(2,4-dichlorophenoxy)acetic acid] and 0.5, 1.1, or 2.2 kg ae/ha of clopyralid (3,6-dichloro-2-pyridinecarboxylic acid) were applied at three Utah sites. The 2,4-D and 1.1 or 2.2 kg/ha of clopyralid effectively controlled mountain big sagebrush (Artemisia tridentataNutt. # ARTTR ssp.vaseyana). Applications of 2.2 kg/ha of 2,4-D resulted in 84% mortality of antelope bitterbrush [Purshia tridentata(Pursh.) DC] and killed 96% of the Saskatoon serviceberry (Amelanchier alnifoliaNutt.). Clopyralid applications of 2.2 kg/ha killed only 5% of the antelope bitterbrush and 6% of the Saskatoon serviceberry. Thus, clopyralid is an effective alternative to 2,4-D for control of mountain big sagebrush when the desirable shrubs antelope bitterbrush and/or Saskatoon serviceberry are present.
Difference in Herbicide Resistance to Various Taxonomic Populations of Common Lambsquarters (Chenopodium album) and Late-Flowering Goosefoot (Chenopodium strictum) in Hungary
Authors: Solymosi Peter , Lehoczki Endre , Laskay Gábor
Published: May 2019

Various populations of common lambsquarters (Chenopodium albumL. # CHEAL) and late-flowering goosefoot (Chenopodium strictumRoth. # CHESG) plants were studied at the eight-to ten-leaf stage. Prior to measurement of fluorescence induction, the detached leaves were vacuum infiltrated with unformulated atrazine [6-chloro-N-ethyl-N′-(1-methylethyl)-1,3,5-triazine-2,4-diamine], diuron [N′-(3,4-dichlorophenyl)-N,N-dimethylurea], and pyrazon [5-amino-4-chloro-2-phenyl-3(2H)-pyridazinone]. The fluorescence induction measurements were then made 1 h after adaptation in the dark. The fluorescence induction curves of intact leaves were recorded with a laboratorybuilt apparatus. A xenon lamp was used to produce the actinic beam. Cytological tests were done on meristematic cells of the root tips of the seedlings treated in 2 nM 8-hydroxyquinoline. The cytotypes were hexaploids (among which were atrazine-susceptible, pyrazon-susceptible, atrazine-resistant, and pyrazon-tolerant populations), and tetraploids (among which were atrazine-susceptible and atrazine-tolerant populations).
Characteristics of Atrazine-Resistant Biotypes of Three Grass Weeds
Authors: Yaacoby Tuvia , Schonfeld Mordechay , Rubin Baruch
Published: May 2019

Three triazine-resistant biotypes of grass weeds, hood canarygrass (Phalaris paradoxaL. # PHAPA), ryegrass (Lolium rigidumGaud.), and slender foxtail (Alopecurus myosuroidesHuds. # ALOMY) were collected along roadsides on the coastal plain of Israel that had been treated repeatedly withs-triazine herbicides. Resistant biotypes (R) survived up to 4 kg ai/ha of atrazine [6-chloro-N-ethyl-N′-(1-methylethyl)-1,3,5-triazine-2,4-diamine] applied pre-and postemergence, while susceptible (S) biotypes were killed by 0.25 kg/ha. R and S biotypes were equally sensitive to diuron [N′-(3,4-dichlorophenyl)-N,N-dimethylurea]. Electron transport in chloroplasts isolated from R biotypes was not affected by atrazine, whereas in S biotypes electron transport was inhibited 50% by 0.4 to 1.0 μM atrazine. Chloroplasts from both biotypes were equally sensitive to diuron. These data indicate that the R biotypes have a plastidic mode of resistance to atrazine. In addition, seedlings of R biotypes exhibited resistance to triazinone herbicides. The R biotype of hood canarygrass was more tolerant to postemergence application of diclofop {(±)-2-[4-(2,4-dichlorophenoxy)phenoxy] propanoic acid}.
Responses of Soybean (Glycine max) and Three C4Grass Weeds to CO2Enrichment During Drought
Authors: Patterson David T.
Published: May 2019

In controlled-environment chambers at 29/33 C day/night and 1000 μE·m-2·s-1photosynthetic photon flux density (PPFD), increasing the CO2concentration from 350 to 675 ppm (v/v) did not affect leaf area or total dry weight of well-watered plants of barnyardgrass [Echinochloa crus-galli(L.) Beauv. # ECHCG], goosegrass [Eleusine indica(L.) Gaertn. # ELEIN], or southern crabgrass [Digitaria ciliaris(Retz.) Koel. # DIGSP] after 30 days. However, the whole plant transpiration rate per unit leaf area decreased, and the water use efficiency increased, in response to CO2enrichment. In a subsequent experiment, with water availability limited by an imposed drought, CO2enrichment reduced the effects of water stress and significantly increased leaf area and total dry weight of the three C4grasses and soybean [Glycine max(L.) Merr. ‘Ransom’]. Growth enhancement in response to CO2enrichment was greater in soybean than in the C4grasses. By improving their water economy, CO2enrichment can increase the growth of both C3and C4plants under water stress. However, growth stimulation can be expected to be greater in C3plants.
Concentration of 2,4,5-T, Triclopyr, Picloram, and Clopyralid in Honey Mesquite (Prosopis glandulosa) Stems
Authors: Bovey Rodney W. , Hein Hugo , Meyer Robert E.
Published: May 2019

Triclopyr {[(3,5,6-trichloro-2-pyridinyl)oxy] acetic acid}, 2,4,5-T [(2,4,5-trichlorophenoxy)acetic acid], picloram (4-amino-3,5,6-trichloro-2-pyridinecarboxylic acid), and clopyralid (3,6-dichloro-2-pyridinecarboxylic acid) were applied to honey mesquite (Prosopis glandulosaTorr. # PRCJG) on seven different dates about every 3 weeks from May to September in 1980 and 1981. Concentrations of 2,4,5-T or triclopyr in stem tissue were usually less than 2 μg/g fresh weight regardless of date of application. Concentrations of picloram and clopyralid were as high as 11 and 22 μg/g fresh weight, respectively, in upper stem phloem at some dates of application. Higher concentrations of all herbicides were detected in upper stem phloem than in the upper stem xylem or basal stem phloem or xylem. More herbicide tended to be detected in stems when herbicides were applied early (May and June) than late (August and September) in the season. Concentrations of triclopyr and picloram recovered from honey mesquite stems were about 25% greater at 3 than at 30 days after treatment, whereas concentrations of 2,4,5-T and clopyralid were about 50% greater at 3 than at 30 days after application.
Reducing Velvetleaf (Abutilon theophrasti) and Giant Foxtail (Setaria faberi) Seed Production with Simulated-Roller Herbicide Applications
Authors: Biniak Barbara M. , Aldrich Richard J.
Published: May 2019

The potential of preventing seed production and reducing seed viability of weeds that commonly grow taller than soybeans [Glycine max(L.) Merr. ‘Williams 82’] was evaluated. Chlorflurenol (2-chloro-9-hydroxy-9H-fluorene-9-carboxylic acid), chlorsulfuron {2-chloro-N-[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino] carbonyl] benzenesulfonamide}, and glyphosate [N-(phosphonomethyl)glycine] were evaluated against sparse stands of velvetleaf (Abutilon theophrastiMedik. # ABUTH) and giant foxtail (Setaria faberiHerrm. # SETFA) growing in soybeans. Simulated-roller applications of all three herbicides significantly reduced seed production and germination of both weeds, although glyphosate was more effective than were the other two. Applications during early flowering of velvetleaf and early heading of giant foxtail reduced seed production more than later applications when some seeds were present. With the early application of glyphosate, 99% prevention of velvetleaf and 96% prevention of giant foxtail seed production were attained. With the early glyphosate application, germination of seeds produced was reduced by 50% in velvetleaf and by 95% in giant foxtail. Soybean yields were not reduced by either glyphosate or chlorflurenol but were drastically reduced by chlorsulfuron.
Herbicidal Effects on Crownvetch Rhizobia and Nodule Activity
Authors: Cardina John , Hartwig Nathan L. , Lukezic Felix L.
Published: May 2019

Two strains of crownvetch (Coronilla variaL. # CZRVA) rhizobia were cultured in vitro with various rates of atrazine [6-chloro-N-ethyl-N′-(1-methylethyl)-1,3,5-triazine-2,4-diamine] and bifenox [methyl 5-(2,4-dichlorophenoxy)-2-nitrobenzoate]. Growth, measured turbidimetrically over 48 h, was similar for both strains. Atrazine and bifenox significantly reduced bacterial growth after 14 and 36 h, respectively, only at the highest concentrations tested (463 μM atrazine and 292 μM bifenox). Since growth of crownvetch rhizobia was apparently not affected by rates of atrazine or bifenox above reasonable soil solution concentrations, it is likely that herbicidal effects on nodulation were due to toxicity to the host plant rather than toxicity to these bacteria. In a growth chamber experiment, total nodule activity (TNA) and carbon dioxide exchange rate (CER) were measured simultaneously in an effort to distinguish direct atrazine effects on nodule function from indirect effects due to inhibition of photosynthesis and a resulting decrease in photosynthate supply to nodules. When 5 and 50 mg atrazine per kg soil were applied to intact plants, CER was severely reduced within 24 h, but similar reductions in TNA were not observed until 48 h after treatment. Total nodule activity was reduced similarly by atrazine and defoliation; the application of atrazine to defoliated plants did not inhibit TNA more than did defoliation alone. The data indicate that reductions in crownvetch nodule activity by atrazine are due to inhibition of photosynthesis or other processes rather than direct toxicity to N fixation.
Seasonal Trends of Total Nonstructural Carbohydrates in Lindheimer Pricklypear (Opuntia lindheimeri)
Authors: Potter Robert L. , Petersen Joseph L. , Ueckert Darrell N.
Published: May 2019

Pricklypear (Opuntiaspp.) is a major constraint to rangeland livestock production in several resource areas of Texas. The phenological and physiological stages of pricklypear have heretofore been ignored in relation to timing of herbicide applications. The phenology, percent total nonstructural carbohydrates (TNC), and water content in Lindheimer pricklypear (Opuntia lindheimeriEngelm. # OPULI) were monitored biweekly for 2 yr in the southern Rolling Plains of Texas. TNC in cladophylls, crowns, and roots declined sharply from bud break (late March to late April) through the period of rapid development of new cladophylls and fruits, with minimum levels occurring during mid-July to early August. This depletion period coincides with the period when control has traditionally been attempted with broadcast applications of translocated herbicides with erratic results. Replenishment of TNC in cladophylls and basal crowns occurred during August through March or mid-April; major increases in root TNC occurred from early autumn through midwinter. Application of herbicide in late summer, autumn, or winter when TNC is being replenished in organs bearing meristematic tissue may be more effective for pricklypear control if the herbicide is translocated with photosynthates.
Effect of Various Flavor-Related Compounds on Germination of Curly Dock Seed (Rumex crispus) and Curly Dock Rust (Uromyces rumicis)
Authors: French Richard C. , Kujawski Peter T. , Leather Gerald R.
Published: May 2019

Chemicals that stimulate germination of curly dock seed (Rumex crispus L. # RUMCR) and urediniospores of curly dock rust [Uromyces rumicis Schum. (Wint.)], an obligate parasite of this weed, were studied and compared. Methyl salicylate, benzyl cyanide, and benzonitrile were the best stimulators of germination of curly dock seed. The compounds tested were most effective at concentrations ranging from 250 to 1000 μl/L. A 500 μl/L concentration of methyl salicylate caused 99% of the curly dock seed to germinate. Exposure to volatiles from 10 μl methyl salicylate or octyl cyanide for 16 to 24 h was required for maximum stimulation of curly dock seed germination in 10 days. Benzonitrile, methyl-2,4-dihydroxybenzoate, 3-cyanophenol, 2-heptanone, and benzaldehyde were the most effective of 45 compounds tested on urediniospores of curly dock rust. Benzonitrile was most active of 19 compounds tested on both seed and spores. Benzyl cyanide, 4-methoxybenzonitrile, benzaldehyde, and methyl 2,4-dihydroxybenzoate also were active on both propagules.
Establishment and Rooting of Zoysiagrass (Zoysia japonica) as Affected by Preemergence Herbicides
Authors: Fry Jack D. , Dernoeden Peter H. , Murray J. Jack
Published: May 2019

Preemergence applications of herbicides were evaluated for their effect on establishment of zoysiagrass (Zoysia japonicaSteud.) with competition from either smooth crabgrass [Digitaria ischaemum(Schreb.) Muhl. # DIGIS] or goosegrass [Eleusine indica(L.) Gaertn. # ELEIN]. When ‘Meyer’ and ‘Belair’ zoysiagrass plugs were grown in sand and treated in the greenhouse, none of the herbicides reduced root weight or length. When plugs were grown in a Sassafrass sandy loam, bensulide {O,O-bis(1-methylethyl)-S-[2-[(phenylsulfonyl)amino] ethyl] phosphorodithioate} and simazine (6-chloro-N,N′-diethyl-1,3,5-triazine-2,4-diamine) reduced root weight, and simazine reduced root length of Belair, but not Meyer. In smooth crabgrass-infested field plots, more stolons were produced from Meyer plugs treated with simazine, oxadiazon {3-[2,4-dichloro-5-(1-methylethoxy)phenyl]-5-(1,1-dimethylethyl)-1,3,4-oxadiazol-2-(3H)-one}, and siduron [N-(2-methylcyclohexyl)-N′-phenylurea] than plugs treated with bensulide, metribuzin [4-amino-6-(1,1-dimethylethyl)-3-(methylthio)-1,2,4-triazin-5(4H)-one], or the untreated control. At the end of two growing seasons, metribuzin-treated plots had significantly less zoysiagrass than other plots. Oxadiazon, DCPA (dimethyl tetrachloroterephthalate), and siduron enhanced the field establishment rate where Meyer zoysiagrass was competing with high populations of smooth crabgrass.
Accuracy and Precision of Analyses for 2,4-D and Picloram in Streamwater by Ten Contract Laboratories
Authors: Norris Logan A.
Published: May 2019

In a test of laboratory precision and accuracy, streamwater samples fortified with 0, 10, or 50 μg ae/L 2,4-D [(2,4-dichlorophenoxy)acetic acid] and picloram (4-amino-3,5,6-trichloro-2-pyridinecarboxylic acid) were submitted in quadruplicate for residue analysis to 10 laboratories that analyze samples for a fee. Varying amounts of the herbicides were detected by eight laboratories, and two reported no residues. Analyses from most laboratories had a negative bias (ranging from −2 to −92%), although a positive bias appeared in a few instances. Precision was highly variable, the coefficient of variation ranging from 3.4 to 200%. The accuracy range in 19 of 20 cases was ±100 to ±78% for 10 and 50 μg/L 2,4-D and ±100 to ±114% for 10 and 50 μg/L picloram, respectively. Results show that careful selection of contract laboratories and a quality assurance program should be part of monitoring for water contamination with herbicides.
Efficacy of Ethylene as a Germination Stimulant ofStriga hermonthicaSeed
Authors: Bebawi Faiz F. , Eplee Robert E.
Published: May 2019

Ethylene gas stimulated seed germination of the pearl millet [Pennisetum americanum(L.) K. Schum] strain ofStriga hermonthica(Del.) Benth. # STRHE) in two soil types in the North Kordofan Region of Sudan. Soils were the noncracking clay pediplain or ‘Gardud’, in Arabic, and the stabilized sand locally called ‘Qoz’. Ethylene at 1.5 kg ai/ha induced greater seed germination (suicidal seed germination) in the Gardud soil than in the Qoz soil. However, ethylene at 3.0 kg ai/ha was better on Qoz than Gardud soil. The effect of injection depth of ethylene was dependent on soil type. Ethylene was more effective when injected at a 15-cm depth in the Gardud soil and at a 30-cm depth in the Qoz soil. The viable population ofS. hermonthicaseed was reduced by suicidal seed germination at soil depth to 60 cm and to a horizontal distance of 25 cm from the point of ethylene injection. Ethylene-induced germination reduced seed population by 67 and 34% in Gardud and Qoz soils, respectively. A single injection of ethylene diffused up to 300 cm horizontally and up to 60 cm vertically and caused 12.6 and 8.5% reduction in viable 5.hermonthicaseed in Gardud and Qoz soils, respectively. The potential of ethylene gas as an effective tool in striga control operations in a pediplain and stabilized sand soil such as is found in N. Kordofan is dependent upon the availability of the gas and the injection apparatus and the economics of its application.
The Response of Wild Garlic (Allium vineale) to the Timing of Spray Applications of Chlorsulfuron
Authors: Leys Andrew , Slife Fred W.
Published: May 2019

The response of wild garlic (Allium vinealeL. # ALLVI) to fall and spring applications of chlorsulfuron {2-chloro-N-[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl) amino] carbonyl] benzenesulfonamide} was evaluated in the field in 1982 and 1983. In natural stands, application of 20 g ai/ha in the spring reduced aerial bulblet production by 99%. Applications in the fall were much less effective (20 g/ha reduced aerial bulblet production by 59%), but were still better than the standard treatment of 2,4-D applied in the spring (840 g ae/ha reduced aerial bulblet production by only 45%). In planted stands, chlorsulfuron was applied preemergence at two locations at 10 and 20 g/ha in the fall, and postemergence in early fall, late fall, early spring, and late spring. All treatments reduced aerial and underground bulb production, but spring applications were much more effective than any of the fall treatments. Application of 20 g/ha of chlorsulfuron in late spring (mid-to-late April) reduced aerial and underground bulb production by greater than 95%. At this time the old bulb reserves were exhausted, and the scape and new bulbs were at an early and rapid stage of development.
Metribuzin and Chlorsulfuron Effect on Grain of Treated Winter Wheat (Triticum aestivum)
Authors: Anderson Randy L.
Published: May 2019

A field experiment was conducted to determine the influence of metribuzin [4-amino-6-(1,1-dimethylethyl)-3-(methylthio)-1,2,4-triazin-5(4H)-one] and/or chlorsulfuron {2-chloro-N-[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino]carbonyl)benzenesulfonamide} on germination, coleoptile growth, and mineral accumulation of seed from treated parent plants. The herbicides were applied postemergence in the spring to ‘Vona’ and ‘Centurk’ winter wheat (Triticum aestivumL.). The rate of metribuzin was 360 g ai/ha, with chlorsulfuron applied at 18, 35, or 70 g/ha. Metribuzin reduced grain yields of both varieties approximately 40%, whereas chlorsulfuron at the higher rates reduced grain yields of only Vona. Seed germination was not affected by either herbicide, but metribuzin, when applied alone, reduced coleoptile growth of Vona seed. The addition of chlorsulfuron to metribuzin eliminated this growth reduction. The mineral concentration of the seed of both varieties indicated that metribuzin and chlorsulfuron did not affect mineral translocation to the seed by the parent plant.
Variation in Response of Four Nightshades (Solanumspp.) to Herbicides
Authors: Ogg Alex G.
Published: May 2019

In field experiments at Prosser, WA, black nightshade (Solanum nigrumL. # SOLNI), eastern black nightshade (S. ptycanthumDun. # SOLPT), American black nightshade (S. americanumMill. # SOLAM), hairy nightshade (S. sarrachoidesSendtner # SOLSA), and sometimes accessions within a species responded differentially to herbicides applied preplant incorporated, preemergence, or postemergence. Also, the response of the nightshades to some of the herbicides varied significantly between years. Generally, black nightshade was more tolerant of herbicides than were the other three species. An accession of black nightshade from England and an accession of eastern black nightshade from Minnesota were the most tolerant of herbicides of eight accessions evaluated. Of the 25 herbicides evaluated, preplant-incorporated applications of ethalfluralin [N-ethyl-N-(2-methyl-2-propenyl)-2,6-dinitro-4-(trifluoromethyl) benzenamine] and preemergence applications of alachlor [2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)acetamide], chloramben (3-amino-2,5-dichlorobenzoic acid), lactofen [1′-(carboethoxy)ethyl 5-[2-chloro-4-(trifluoromethyl) phenoxy]-2-nitrobenzoate], and metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl] acetamide] controlled all species best. These herbicides reduced the oven-dry weights of both accessions of all four species of nightshades by 93% or more. Nightshades varied widely in their response to the thiocarbamates.
A Washer for Removing Thickened Roots from Soil1,2
Authors: Carlson Steven J. , Donald William W.
Published: May 2019

A root washer was constructed which rapidly separated Canada thistle [Cirsium arvense (L.) Scop. # CIRAR] roots larger than 1.3-mm diam with 96% or greater efficiency from cohesive clay soil. The washer removed 93 ± 15% of 43 200 cm clay soil from Canada thistle roots in 2 h. Small residual soil clods and organic debris were removed by hand after washing. The washing action did not damage the root system. From 4 to 6 h were required to wash the large Canada thistle roots from an equivalent volume of clay soil by hand, without using the washer. Rhizomes, seeds, and tubers also may be separated from soil with the washer. The tank and frame of this washer are durable, and moving parts such as bearings can be replaced easily.
Interaction of Propanil and Selected Insecticides on Rice (Oryza sativa)
Authors: Khodayari Khosro , Smith Roy J. , Tugwell N. Philip
Published: May 2019

Field experiments determined the potential interaction of insecticides and propanil [N-(3,4-dichlorophenyl) propanamide] in drill-seeded rice (Oryza sativaL. ‘Bond’). The carbamate insecticides carbaryl (1-naphthylmethylcarbamate) and methomyl {S-methylN-[(methylcarbamoyl) oxy] thioacetimidate} interacted more severely with propanil than the organophosphate methyl parathion [O,O-dimethylO-(p-nitrophenyl) phosphorothioate] in emulsifiable or encapsulated formulations. Carbaryl and methomyl injured rice vegetatively when applied from 7 days before to 4 days after propanil. Carbaryl was the only insecticide that interacted with propanil to reduce rice grain yield. Insecticides interacted adversely with propanil on rice grain yield when they were applied 2 days before propanil treatment. Insecticide interactions with propanil from most to least phytotoxic to rice plants for all times of application were: carbaryl > methomyl > emulsifiable methyl parathion > encapsulated methyl parathion.
Effects of Adjuvants and Environment During Plant Development on Glyphosate Absorption and Translocation in Field Bindweed (Convolvulus arvensis)
Authors: Sherrick Stewart L. , Holt Harvey A. , Hess F. Dan
Published: May 2019

Absorption and translocation of glyphosate [N-(phosphonomethyl)glycine] with and without adjuvants were examined in field bindweed (Convolvulus arvensisL. # CONAR) to develop an understanding of the influence of selected adjuvants and environment before application on glyphosate activity. Light intensity and humidity during plant development resulted in differences in14C-glyphosate absorption. When applied in water or with an oxysorbic (20 POE) (polyoxyethylene sorbitan monolaurate) adjuvant, an average of 9% of the glyphosate was absorbed in plants grown in high light intensity, low humidity (HLLH) before treatment, compared to an average of 21% in plants grown in low light, high humidity (LLHH) before treatment, respectively. Amounts of epicuticular wax on HLLH field bindweed were almost three times as great as on LLHH leaves and may explain absorption differences. No differences in glyphosate absorption were observed between glyphosate applied with oxysorbic or no adjuvant even though the oxysorbic adjuvant effectively reduces surface tension. Absorption was increased two- to threefold with a polyethoxylated tallow amine adjuvant (MON 0818) compared to no adjuvant. Unlike absorption without adjuvant or with oxysorbic adjuvant, there were few absorption differences in plants grown in different environments before application. Absorption continued for 24 to 36 h after application regardless of adjuvant. Reductions in MON 0818 concentration and subsequent necrosis resulted in increased movement of radioactivity away from the site of application.
Integration of Molinate use with Water Management for Red Rice (Oryza sativa) Control in Water-seeded Rice (Oryza sativa)
Authors: Baker John B. , Sonnier Earl A. , Shrefler James W.
Published: May 2019

Integration of preplant-incorporated molinate (S-ethyl hexahydro-1H-azepine-1-carbothioate) at 4.5 kg ai/ha and a brief postseeding drainage period in water-seeded rice (Oryza sativaL.) gave the best red rice (Oryza sativaL. # ORYSA) control without a significant reduction in cultivar stand density. This combination of practices provided higher cultivar grain yield and lower red rice grain yield than any water management practice alone. Continuous-flood water management provided a substantial reduction in red rice stand density, but it also caused a significant reduction in the cultivar stand density. Under the reduced stand density conditions, the red rice was very competitive and yielded more than the cultivar. Although brief drainage alone gave a significantly lower level of red rice control, it had no significant effect on the cultivar stand density, and the red rice and cultivar yields were not significantly different from the continuous-flood yields. Prolonged drainage had the highest red rice and cultivar stand densities and the highest red rice grain yield, but the cultivar yield was not significantly different from the other plots that were not treated with herbicide. Although this treatment gave the highest total grain yield, its composition had the highest percentage of red rice. Puddling the seedbed did not alter the stands or yields of red rice or cultivar compared to the nonpuddled plots with the same water management and herbicide rate. The application of molinate as a preplant-incorporated treatment or as a preplant postflood treatment before or after puddling gave results that were not significantly different from each other. The superior performance of preplant application of molinate in water-seeded rice in conjunction with a brief postseeding drainage period provides an excellent tool for red rice suppresion.
Bioeconomic Modeling to Simulate Weed Control Strategies for Continuous Corn (Zea mays)
Authors: King Robert P. , Lybecker Donald W. , Schweizer Edward E. , Zimdahl Robert L.
Published: May 2019

Grass and broadleaf weed densities and seed numbers, weed control practices, and grain yields were included in a bioeconomic model that evaluates alternative weed management strategies for continuous corn (Zea maysL.). Weed seed numbers in soil and herbicide carry-over provided intertemporal links. Four weed management strategies – two fixed, one mixed, and one flexible – were evaluated with annualized net returns as the performance indicator. The flexible strategy (weed control based on observed conditions) had the largest annualized net return for high and low initial weed seed numbers. The fixed weed management strategy (weed control predetermined) of an annual application of only a preemergence herbicide ranked second in terms of annualized net returns for high weed seed numbers. The mixed weed management strategy of alternative year applications of preemergence herbicide and “as needed” applications of postemergence herbicide ranked second for low initial weed seed numbers. The fixed weed management strategy of alternate year application of preemergence herbicide only generated the lowest annualized net return, regardless of initial weed seed numbers.
DeVine®—The Way It Was Developed—An Industrialist's View
Authors: Kenney Donald S.
Published: May 2019

The use of biological control agents for the control of noxious pests is not new conceptual research. There are examples that predate by centuries the modern use of both herbicides and insecticides. For example, the successful control of insects by biological control was shown in 1762 by the introduction of the Mynah bird (Gracula religiosa Linnaeus) from India to Mauritius (4). In 1888, the Vedalia beetle (Rodolia cardinalis Muslant) was introduced to control the cottony-cushion scale (Icerya purchasi Maskell) of citrus (3). An example of biological control of weeds was reported in 1863 when it was observed that an infestation of prickly pear cactus (Opuntia humifusa Raf. # OPUHU) was decimated by the imported cochineal insect (Dactylopius tomentosus Lam.) (5).