bluuebunny/crossref_metadata_2025 huggingface dataset:
Combined approach for paediatric recurrent antrochoanal polyp: a single-centre case series of 27 children
Authors: Mantilla E , Villamor P , De La Torre C , Álvarez-Neri H
Published: May 2019

Objective

To compare functional endoscopic sinus surgery with a combined approach (functional endoscopic sinus surgery plus Caldwell–Luc procedure) for the treatment of paediatric antrochoanal polyp, in terms of antrochoanal polyp recurrence and safety.

Method

This retrospective case series comprises 27 paediatric patients with recurrent antrochoanal polyp, treated from January 2010 to January 2018.

Results

The average age of the patients at the time of diagnosis was 10.4 ± 2.49 years. The recurrence rate after functional endoscopic sinus surgery alone was 72.9 per cent, compared with 12.5 per cent after functional endoscopic sinus surgery plus the Caldwell–Luc procedure (p < 0.00001). No complications were reported during surgery or follow up.

Conclusion

The correct identification of the origin of the antrochoanal polyp and an adequate returning of maxillary ventilation by widening the ostium can prevent recurrences. Although functional endoscopic sinus surgery continues to be the ‘gold standard’ for antrochoanal polyp treatment, in cases of revision surgery, a combined approach could ensure the complete removal of the polyp through the two openings.
Overview: extreme environments
Authors: Tinsley R. C.
Published: May 2019

An important element in most approaches to the subject of parasitism is the consideration of environment. Parasites are set apart within animal ecology because they experience two environments, one the ‘external’ conditions and the other created by the living body of the host. As in any ecological system, external environmental conditions have a major influence on life history parameters: these conditions may be experienced directly by ‘off-host’ stages of a parasite or, to a greater or lesser extent, indirectly through the body of the host. However, uniquely in parasitic associations, the internal (host) environment has a dual influence on the physiological conditions encountered by parasites: first, the host buffers the external conditions (by homeostatic mechanisms moderating environmental fluctuations, by behavioural responses selecting appropriate habitat conditions, etc.), but second, the host creates a suite of hostile factors associated with immune defence. This living, reactive environment has no parallels elsewhere in free-living animal ecology: it has the characteristic of reacting specifically to kill the organisms within its boundaries.
Absorption, translocation, and metabolism of glufosinate in five weed species as influenced by ammonium sulfate and pelargonic acid
Authors: Pline Wendy A. , Wu Jingrui , Hatzios Kriton K.
Published: May 2019

Absorption, translocation, and metabolism of14C-glufosinate were studied in three annual and two perennial weed species. Young seedlings ofSetaria faberi, Chenopodium album, Cassia obtusifolia, Solanum carolinense, andAsclepias syriacawere treated with foliar-applied14C-glufosinate, and plant tissues were harvested 12, 48, and 72 h after treatment (HAT). Absorption of14C-glufosinate was initially rapid, but increased only slightly after 12 h in all species. Glufosinate absorption was highest inS. carolinense(73% of applied radioactivity), followed byS. faberi(54%),C. obtusifolia(44%),C. album(41%), andA. syriaca(37%) 72 HAT. Translocation of radioactivity out of the treated leaf was species dependent and did not increase much with time in all weed species.S. carolinenseandS. faberitranslocated the highest amounts of absorbed radioactivity out of the treated leaf with 49 to 59% moving to the upper foliage.S. faberitranslocated the highest amount of absorbed radioactivity to the roots (12 to 14%), whileC. albumtranslocated the least (2 to 3%). TLC analysis of plant extracts showed that14C-glufosinate was not metabolized inS. faberi, C. obtusifolia, S. carolinense, andA. syriaca. A glufosinate metabolite with an Rf value matching that of methyl-phosphinico propionate was detected inC. album. Treatment with ammonium sulfate (AMS) increased glufosinate absorption inS. faberiandC. obtusifolia12 HAT, but decreased absorption inC. album. Treatment with pelargonic acid (PA) did not affect glufosinate absorption in any of the species tested. Treatment with AMS and PA did not affect glufosinate translocation in any of the five weed species. Treatment with AMS and PA did not influence the metabolism of glufosinate in any of the five weed species studied. These results show that differential absorption and translocation seem to explain the greater sensitivity of the annual and perennial weeds to glufosinate. Treatment with ammonium sulfate may increase the efficacy of glufosinate in perennial weeds.
Thermal dependence of pyrithiobac efficacy inAmaranthus palmeri
Authors: Light Ginger G. , Dotray Peter A. , Mahan James R.
Published: May 2019

Variability in weed control following pyrithiobac applications has been observed under field conditions. The influence of temperature on this variability was investigated. Results from field studies performed over two growing seasons identified plant and air temperatures at the time of herbicide treatment that correlated with whole-plant efficacy differences. Based on the field data, weed control with pyrithiobac was acceptable at application temperatures of 20 to 34 C. To investigate a potential source of thermal limitations on pyrithiobac efficacy, the thermal dependence of in vitro inhibition of acetolactate synthase (ALS), the site of action for pyrithiobac, was examined. A crude leaf extract of ALS was obtained fromAmaranthus palmeri. Relative inhibitor potency (I50) values were obtained at saturating substrate conditions for temperatures from 10 to 50 C. Regression analysis of field activity against I50values showed the two data sets to be highly correlated (R2= 0.88). The thermal dependence of enzyme/herbicide interactions may provide another means of understanding environmental factors limiting herbicidal efficacy and predicting herbicide inhibition at the whole-plant level.
Effect of burial depth on emergence ofPanicum repens
Authors: Hossain Amzad , Ishimine Yukio , Akamine Hikaru , Murayama Seiichi , Moslem Uddin S. M. , Kuniyoshi Kiyoshi
Published: May 2019

In glasshouse experiments,Panicum repensrhizomes with more than two nodes emerged from soil depths of 1 to 20 cm. Emergence from one-node rhizomes was greatly reduced at depths more than 5 cm. In contrast, culm emergence from ginger like rhizomes decreased when burial depth (BD) was greater than 20 to 30 cm.P. repensemerged from deeper soil levels with an increasing number of nodes per cutting. Culms emerged from 36% of total underground regenerative organs. About 75 and 95% of the emerged culms were recorded 30 and 60 d after burial, respectively, and 91% emergence was recorded from 20-cm BD. In field studies, only 9% of nodes produced culms following cross-plowing. About 61 and 67% of the emerged culms were recorded 50 and 60 d after land preparation, respectively. Results indicate that mechanical and chemical control methods could be most effective forP. repenswhen applied approximately 50 d after land preparation. Burying deeper than 30 cm by deep plowing and reducing rhizome length by cross-plowing might effectively reduce emergence ofP. repens.
Effect ofDactylaria higginsiion interference ofCyperus rotunduswithL. esculentum
Authors: Kadir J. B. , Charudattan R. , Stall W. M. , Bewick T. A.
Published: May 2019

Greenhouse experiments were conducted to evaluate the effect of the fungusDactylaria higginsiion the interference ofCyperus rotundus(purple nutsedge) withLycopersicon esculentum(tomato ‘Agroset').Cyperus rotundusplants established from tubers were planted at initial densities equivalent to 40, 80, 160, and 320 tubers m−2withL. esculentumin 35-cm-diam pots.Cyperus rotundusplants were inoculated by spraying with a spore suspension ofD. higginsiicontaining 0.5% Metamucil as a carrier. The treatments were Metamucil only, 104conidia ml−1+ Metamucil, or 106conidia ml−1+ Metamucil. In the absence ofD. higginsii, C. rotundusat densities of 80, 160, and 320 tubers m−2reducedL. esculentumyield by 14, 68, and 70%, respectively. In contrast, yield ofL. esculentumtreated withD. higginsiiat 106conidia ml−1was equal to that in the weed-free control. The rate of disease increase (rG) was higher in treatments with 106conidia ml−1(rG= 0.126 to 0.136) compared to 104conidia ml−1(rG= 0.046 to 0.050). At 106conidia ml−1D. higginsiireduced the interference fromC. rotundus, controlledC. rotundusbetter, and increasedL. esculentumyield compared to the weedy checks.
Modeling effects of spatial patterns on the seed bank dynamics ofAlopecurus myosuroides
Authors: Gonzalez-Andujar J. L. , Perry J. N. , Moss S. R.
Published: May 2019

A spatially explicit metapopulation neighborhood model was extended to encompass the seed bank dynamics of the annual weedAlopecurus myosuroidesHuds. (blackgrass), growing in U.K. winter wheat crops established after noninversion tillage. The effects of the initial spatial pattern of infestation, herbicide, and combine harvesting on seed bank densities and on expected yield losses of the infested crop were studied within a 634 m2area. In the absence of herbicide, all seed bank populations were large and typical of values in the literature; those with patchy initial distributions spread quickly over the entire field. The effects of intraspecific competition ensured that even after 10 yr, the average seed bank density from three patterns with the same initial density consistently retained the same rank order: the initially uniform pattern consistently ranked largest; a patchily distributed moderate infestation ranked next; a more patchily distributed heavy infestation ranked least. Expected grain yield losses sometimes exceeded 40%. With the introduction of a herbicide, seed densities declined exponentially, but the rank order with regard to spatial pattern remained. Relatively dense patches occasionally persisted for longer than 10 yr. The economic threshold for treatment was achieved within 2 and 5 yr, depending on the infestation pattern, but the model predicted that it would take many more than 10 yr before infestations could be completely eliminated. The effects of harvesting by combine were modeled. In all cases, the speed of the spread of infestation along a row appeared to be largely due to the combine rather than to natural dispersal or other cultivation practices. The proportion of seeds removed by the combine was an important determinant of the number of years required to drive the population below the economic threshold and of the probability of long-term eradication of the weed metapopulation.
Effect of BAS-145–138 on the phytotoxicity of imazaquin and metsulfuron-methyl
Authors: Seguin Alain , Milhomme Henri , Satchivi Norbert M.
Published: May 2019

The influence of the experimental herbicide safener BAS-145–138 on the toxicity of imazaquin and metsulfuron-methyl was investigated in two corn varieties in growth chamber bioassays. BAS-145–138 alone slightly decreased root and shoot growth but this decrease was not dependent on the safener concentration. The imbibition of seeds of both corn varieties with low levels of safener caused substantially less damage in the roots and shoots especially with the highest metsulfuron-methyl doses used in the study. In one variety, the safener significantly increased corn root tolerance to imazaquin and to metsulfuron-methyl 1.5- and 2.3-fold, respectively; the concentrations of both herbicides producing 50% inhibition were higher for safened seedlings. In the other variety, a high antidotal influence of BAS-145–138 imbibition on metsulfuron-methyl was observed in shoot growth.
Physiological response of soybean (Glycine max) and two weed species to thifensulfuron and bentazon combinations
Authors: Lycan Darren W. , Hart Stephen E.
Published: May 2019

Greenhouse and laboratory studies were conducted to determine the effects of bentazon on the crop safety, efficacy, foliar absorption, and translocation of thifensulfuron when it is applied to soybean, velvetleaf, and common lambsquarters. A metabolism study was conducted on soybean. Thifensulfuron applied at 1.1 g ai ha−-1with 28% urea ammonium nitrate (2.5% v/v) and BAS-0904805 (Dash) adjuvant (0.63% v/v) reduced the growth of velvetleaf and common lambsquarters by an average of 91 and 84%, respectively. The addition of 420 g ai bentazon ha−-1had no effect on thifensulfuron efficacy in the weed species. Soybean dry weights were decreased by 58% when thifensulfuron was applied at 2.2 g ha−-1but were decreased by only 36% when bentazon, at 420 g ha−-1, was added. In the absorption study, the addition of bentazon reduced foliar absorption of14C-thifensulfuron into velvetleaf and common lambsquarters 8 and 24 h after treatment (HAT), but absorption into soybean was not affected. Bentazon reduced the translocation of14C from thifensulfuron out of the treated leaves of velvetleaf and common lambsquarters by at least 16 and 11%, respectively, beyond 24 HAT. Soybean translocated 18, 29, and 26% of absorbed14C out of the treated leaflets 24, 72, and 168 HAT, respectively. These translocation values were reduced to 7, 12, and 11%, respectively, when bentazon was tank-mixed with thifensulfuron. Soybean metabolized 35% of recovered14C-thifensulfuron by 24 HAT. Addition of bentazon did not change this level of metabolism. These studies suggest that the physiological basis for the decrease of soybean injury from thifensulfuron, when it is tank-mixed with bentazon, is decreased thifensulfuron translocation.
Time of hilling and interseeding affects weed control and potato yield
Authors: Rajalahti Riikka M. , Bellinder Robin R. , Hoffmann Michael P.
Published: May 2019

The current emphasis on reducing pesticide use has led to increased interest in alternative weed control methods. The purpose of this study was to evaluate the potential of hilling, in combination with subsequent interseeding of cover crops, to control weeds in potato and to determine the impact of these actions on potato yield and insects. Each cover crop, either hairy or lana vetch, oats, barley, red clover, or a combination of oats and hairy vetch, was interseeded, following hilling, 3, 4, or 5 wk after planting (WAP). Hilling and interseeding treatments were compared to a no-cover treatment and a chemical standard, metolachlor (1.7 kg ai ha−-1) plus linuron (1.7 kg ai ha−-1). Cultivation associated with the interseeding operation and cover crops reduced weed density 20 to 27% by 3 wk after interseeding. To prevent excessive competition, cereals interseeded 3 or 4 WAP and vetches interseeded 3 WAP were controlled at a height of 25 to 35 cm using fluazifop (0.22 kg ai ha−-1) plus metribuzin (0.28 kg ai ha−-1). Because of slow growth, it was necessary to control red clover (interseeded 3 WAP), only in 1996, at a height of 15 cm. Control of cereals resulted in a dead mulch that provided 0 to 95% weed control, whereas legumes regrew after herbicide application and provided 45 to 70% weed control. However, an adequate minimum of 70% weed control was achieved only with the chemical standard, cereals (1995 and 1996), and legumes (1996) interseeded 3 WAP when controlled with herbicides. In a dry season (1995), potato yields were highest with the chemical standard, whereas in a season with adequate precipitation (1996), potato yields equivalent to those of the chemical standard were obtained with early interseeding (3 WAP) of cereals. The observed changes in the densities of potato leafhopper and of its natural enemies were unlikely to have any effect on potato yield because of low overall insect populations. Thus, the results suggest that in good growing conditions, early (3 WAP) interseeding of cover crops supplemented with postemergence herbicides may both suppress weeds with 70% less herbicide (ai ha−-1) and provide yields comparable to those associated with conventional potato production.
Biological control of yellow toadflax (Linaria vulgaris) byEteobalea serratellain peppermint (Mentha piperita)
Authors: Volenberg Dean S. , Hopen Herbert J. , Campobasso Gaetano
Published: May 2019

Yellow toadflax is an introduced ornamental perennial that has become a serious weed in Wisconsin peppermint production. Glyphosate is the only labeled herbicide that controls yellow toadflax in peppermint. Other control strategies, either mechanical or cultural, have little effect on the weed in solid stands of peppermint. Previous research has suggested that the root mining mothEteobalea serratellaTr. (Lepidoptera: Cosmopterigidae) may provide effective biological control of yellow toadflax. Therefore, experiments were conducted to determine the host specificity ofE. serratellaand to quantifyE. serratellaroot mining of yellow toadflax. In larval and adult no-choice tests,E. serratellaattacked only yellow toadflax. Other plant species collected fromE. serratella'snatural range were not attacked, neither those closely related to yellow toadflax in the family Scrophulariaceae, nor those closely related to peppermint in the family Labiatae. Root mining byE. serratellareduced root biomass an average of 20% compared to nontreated plants. Peppermint competition alone or in conjunction with root mining byE. serratellareduced root biomass 52 and 65%, respectively, compared to nontreated plants under noncompetitive conditions.E. serratellais host specific for yellow toadflax and demonstrates potential as a biological control agent by contributing to the reduced competitive ability of yellow toadflax in peppermint.
Prescribed burning for control of yellow starthistle (Centaurea solstitialis) and enhanced native plant diversity
Authors: DiTomaso Joseph M. , Kyser Guy B. , Hastings Marla S.
Published: May 2019

Two separate open grassland areas within Sugarloaf Ridge State Park, Sonoma County, CA, were burned for three consecutive years (1993–1995 [Site A] and 1995–1997 [Site B]) for control of yellow starthistle. Burns were conducted in late June to early July following seed dispersal and senescence of desirable grasses and forbs but prior to viable seed production in yellow starthistle. After the first year burn, there was no significant reduction in yellow starthistle cover the following spring and summer. Despite the lack of control, the first year burn reduced the yellow starthistle soil seedbank by 74% and the number of seedlings the following spring by 83%. However, total plant diversity and species richness increased dramatically in the burned areas. This was due primarily to an increase in the number of native broadleaf species. A second burn the next summer (1995–1997 site) reduced seedbank, seedling density, and summer vegetative cover the following year by 94, 92, and 85%, respectively, while maintaining significantly higher native plant cover and richness. A third consecutive summer burn decreased yellow starthistle seedbank and seedling density by 96, 98, and 85%, respectively, in the 1995–1997 burn site. Three consecutive years of burning in the 1993–1995 site reduced yellow starthistle seedbank and seedling density by over 99% and summer vegetative cover by 91%. These results indicate that prescribed burning can be an effective tool for the management of yellow starthistle and can have a long-term benefit on native broadleaf diversity and richness.
Spatial variability of imazethapyr sorption in soil
Authors: Oliveira Rubem S. , Koskinen William C. , Ferreira Francisco A. , Khakural Bhairav R. , Mulla David J. , Robert Pierre J.
Published: May 2019

A significant limitation in using sorption coefficients (Kd) to predict solute transport through natural soils is the spatial variability of soil properties over large field areas. Spatial variability inKdfor imazethapyr was determined on representative samples from a 31.4-ha field, covering a pH range from 4.9 to 7.6 and an organic carbon (OC) range from 1.45 to 5.80 g kg−-1.Kdvaried from 0.18 to 3.78 across the field, with an average value of 1.56. The analysis ofKdvariability showed two distinct patterns in spatial distribution: areas in which pH > 6.25 andKd< 1.5, whereKdvariation is based primarily on pH, and areas in which pH < 6.25 andKd> 1.5, where other soil properties, i.e., OC content, have a significant influence onKdvariation. Based on soil pH distribution, an easily measured property, the field was divided into two potential management areas. This separation allowed identification of portions of the field where herbicide sorption would be minimal, with a relatively higher potential for leaching (i.e., areas withKd< 1.5), and provided a rationale for site-specific imazethapyr application.
Full-season Palmer amaranth (Amaranthus palmeri) interference with cotton (Gossypium hirsutum)
Authors: Rowland Matt W. , Murray Don S. , Verhalen Laval M.
Published: May 2019

Four field experiments were conducted in Oklahoma to measure full-season Palmer amaranth interference on cotton lint yield and fiber properties. Density of the weed ranged from 0 to 12 plants 10 m−1of row. Cotton lint yield vs. weed density fit a linear model for densities ⩽ 8 weeds row−1at Perkins and Chickasha in 1996 and at Alms in 1997. At Perkins in 1997, all densities fit a linear model. For each increase of 1 weed row−1, lint yield reductions were 62 kg ha−1(or 10.7%) and 58 kg ha−1(or 11.5%) at Perkins and at Chickasha in 1996, respectively. At Perkins and Alms in 1997, for each 1 weed row−1, lint yield was reduced 71 kg ha−1(or 5.9%) and 112 kg ha−1(or 8.7%), respectively. Lint yield vs. end-of-season weed volume fit a linear model except at Alms in 1997. For each increase of 1 m3of weed plot−1, cotton lint yield in 1996 was reduced by 1.6 and 1.5% at Perkins and Chickasha, respectively. In 1997 at Perkins and Altus (⩽ 6 weeds), each increase of 1 m3of weed plot−1reduced lint yield 1.6 and 2.3%, respectively. Lint yield vs. end-of-season weed biomass fit a linear model in all four experiments. Lint yield was reduced 5.2 to 9.3% for each increase of 1 kg of weed biomass plot−1. Fiber analyses revealed significant differences for micronaire (fiber fineness) among weed densities in two experiments, marginal significance in a third, and none in a fourth. An intermediate number of weeds often resulted in improved fiber micronaires in these environments. No other fiber properties were influenced by weed density.
Resistance to glyphosate inLolium rigidum.II. Uptake, translocation, and metabolism
Authors: Feng Paul C.C. , Pratley James E. , Bohn Joseph A.
Published: May 2019

Experiments were conducted to determine potential mechanisms of glyphosate resistance inLolium rigidumfrom Australia.14C-Glyphosate uptake, translocation, and metabolism were compared between resistant (R) and sensitive (S) biotypes. The R seed (48118a) represented the F1progenies of plants having survived a 1.73-kg ae ha−1(4.8 L ha−1) application of a Roundup®formulation. The S seed was a sensitive biotype ofL. rigidumfrom Australia. Plants (one to four tillers, 2 to 4 wk old) were presprayed with a high (1.26 kg ae ha−1) or a low (0.28 kg ae ha−1) dose of formulated glyphosate. The first leaf of the first tiller, which was shielded from the spray, was immediately treated with a14C-glyphosate solution via manual application to the adaxial surface. Harvest was made 6 days after treatment (DAT), and glyphosate residues in the leaf wash, treated leaf, roots, and shoots were quantified based on radioactivity as percentage of applied dose. The overall radioactivity recoveries were very good (90.2 to 97.3% of applied dose). R and S plants showed comparable uptake at the high (79.2 vs. 78.0%) or the low (64.0 vs. 64.7%) doses of glyphosate. About one-half of the absorbed glyphosate in both R and S (32.9 to 38.3% appl.) was translocated into the plant and distributed almost equally into roots (13.6 to 16.0% appl.) and shoots (18.1 to 22.6% appl.). Autoradiography studies demonstrated no difference in tissue localization of glyphosate between the R and S plants. For metabolism studies, tissues from individual plants were homogenized in water, and extracts were analyzed by anion exchange high-pressure liquid chromatography (HPLC) with radioactivity detection. There was little to no metabolism of glyphosate in extracts from various tissues of either R or S plants. Based on these results, we conclude that neither uptake, translocation, nor metabolism play a major role in glyphosate resistance inL. rigidum.
Effects of temperature and photoperiod onSetaria viridis
Authors: Swanton Clarence J. , Huang Jian Zhong , Deen William , Tollenaar Matthijs , Shrestha Anil , Rahimian Hamid
Published: May 2019

Understanding the environmental variables influencing the phenological development of weeds is essential for simulation model development. Temperature and photoperiod are important variables governing the phenological development of weeds. Growth cabinet studies were conducted to characterize the phenological development ofSetaria viridisin response to variations in temperature and photoperiod and to determine the duration of the juvenile phase and the effect of temperature and photoperiod on reproductive development.Setaria viridiswas adapted to a temperature range from 6.5 to 47 C. Phenological development ofS. viridiswas described accurately in terms of thermal days (cumulative day degrees above a base temperature) and biological days (Bd: chronological days at the optimum temperature and photoperiod). Four developmental phases ofS. viridiswere described: (1) a juvenile (photoperiod insensitive) phase of 2.6 Bd; (2) a photoperiod-sensitive inductive phase of 2.2 Bd; (3) a photoperiod-sensitive postinductive phase of 6.0 Bd; and (4) a photoperiod-insensitive inductive phase of 10.9 Bd. Photoperiod sensitivity ofS. viridisdid not differ with stage of development when expressed as a rate. Interpretation of constant sensitivity to photoperiod will simplify simulation of weed phenology in mechanistic models.
Effect of tillage systems, N, and cover crop on the composition of weed flora
Authors: Swanton Clarence J. , Shrestha Anil , Roy Robert C. , Ball-Coelho Bonnie R. , Knezevic Stevan Z.
Published: May 2019

The adoption of conservation tillage systems has been challenged by concerns potential weed species shifts. A 9-yr study from 1988 to 1996 was conducted Delhi, Ontario, on a loamy sand soil to evaluate the effect of tillage systems (conventional [CT] and no-till [NT]), cover cropSecale cereale, and nitrogen (N) rate (0, 50, 100, 125, 150, and 200 kg N ha−1) on monocropZea maysL. (corn) yield and changes in the composition of the weed flora. CT consisted of spring moldboard plowing followed by cultivation with a tooth cultivator. Weed counts were taken in the last 3 yr of the study (1994, 1995, and 1996) prior to postemergence herbicide application and then again 2 to 3 wk after herbicide treatment. Composition or the weed flora was analyzed by canonical discriminant analysis (CDA). The relationship between weed density and tillage system was not consistent. Weed species composition differed between CT and NT systems.Chenopodium albumandAmaranthus retroflexuswere associated with CT andDigitaria sanguinaliswith NT. N rate and cover crop did not affect weed density or species composition. Proper management of weeds with herbicides appeared to minimize any long-term effect on the weed flora resulting from varying N rates.Zea maysyields did not differ between CT and NT systems but were greater in both systems with a cover crop at the higher N rates. Disturbance caused by tillage was more important than N rate and cover crop as a mechanism influencing composition of the weed flora.
Interactions between imazamox and diphenylethers
Authors: Unland R. Darren , Al-Khatib Kassim , Peterson Dallas E.
Published: May 2019

A plant response study was conducted in the greenhouse to evaluate interactions between imazamox and acifluorfen, fomesafen, or lactofen. Antagonistic interactions between imazamox and acifluorfen or fomesafen affected control ofI. hederaceaandA. theophrasti21 d after treatment. Combinations of imazamox plus lactofen also antagonized control ofI. hederacea. I. hederaceaabsorbed less14C-imazamox when applied with nonlabeled acifluorfen, but absorption byA. theophrastiwas not affected by the combination. Addition of nonlabeled lactofen did not affect absorption of imazamox inA. theophrastiorI. hederacea.Addition of acifluorfen or lactofen reduced translocation of14C-imazamox to foliage above and below the treated leaf and the root in bothA. theophrastiandI. hederacea.Antagonism ofA. theophrasticontrol was due to reduced translocation of imazamox. Antagonism ofI. hederaceacontrol was due to reduced translocation of imazamox when applied with lactofen or reduced absorption and translocation when applied with acifluorfen.
An improved granular formulation for a mycoherbicidal strain ofFusarium oxysporum
Authors: Hebbar K. P. , Bailey B. A. , Poch S. M. , Lewis J. A. , Lumsden R. D.
Published: May 2019

Modifications were investigated to improve shelf-life or long-term survival upon storage of an extrudedOryza sativaL. (rice) flour : gluten : clay: oil formulation (C7) of a mycoherbicide,Fusarium oxysporumSchlechtend: Fr. f. sp.erythroxylistrain EN4, that causes vascular wilt inErythroxylum cocavar.coca(coca). Fermentor-produced biomass, which contained abundant desiccation-resistant chlamydospores, was incorporated into various adaptations of C7 and stored at room temperature (22 to 25 C) under moderately high (50 to 60%) and low (0 to 5%) relative humidities (RHs). The effect of RH on shelf-life was not significant up to 4 mo of storage, while the presence of oil, added to improve its extrusion, reduced viability significantly. Addition ofGossypium hirsutumL. (cotton) embryo flour or complete elimination of oil from the formulation improved shelf-life from 3 mo to > 12 mo. Shelf-life was further improved by removing the binding agent gluten in the formulation and replacing it with autoclavedO. sativaflour. Ability of the formulations to produce secondary propagules, tested on 1% water agar, indicated that, while adding oil had no effect,G. hirsutumembryo flour increased desiccation-resistant chlamydospore counts but lowered macroconidial counts. Autoclaved rice flour (MR) significantly improved both macroconidial and microconidial counts without affecting chlamydospore counts. None of the formulations affected the total viable propagule counts. When compared with the original formulation (C7), the modification (MRRP7), with MR,G. hirsutumembryo flour, and without oil, was found to have improved shelf-life at higher temperature and RHs and enhanced potential for secondary chlamydospore formation. These characteristics are important for survival of the formulatedF. oxysporumunder less expensive storage conditions and, once applied, for survival in the soil.
Cultivar and age differences in the production of allelochemicals bySecale cereale
Authors: Burgos Nilda R. , Talbert Ronald E. , Mattice John D.
Published: May 2019

Concentrations of DIBOA [2,4-dihydroxy-1,4-(2H)-benzoxazine-3-one] and BOA [2-(3H)-benzoxazolinone], described previously as major allelochemicals inSecale cereale(rye), were determined in eight field-grown cultivars, harvested at booting, using high-performance liquid chromatography (HPLC). Allelochemicals were also quantified in greenhouse-grown cultivar ‘Bates’ harvested 30, 45, 60, and 75 days after planting (DAP). The total production of DIBOA and BOA from field-grownS. cerealeranged from 137 to 1,469 μg g−1dry tissue among the eight cultivars. ‘Bonel’ cultivar had the highest hydroxamic acid (HA) content and ‘Pastar’ the lowest. Bonel also showed the highest activity onEleusine indica(goosegrass) and Pastar the least, in culture plate bioassays using aqueous extracts. HA content in shoot tissue varied withS. cerealematurity. The greatest level of HA in greenhouse-grown Bates was obtained 60 DAP compared to 30 DAP.
Enhancing the margin of selectivity of RPA 201772 inZea mayswith antidotes
Authors: Sprague Christy L. , Penner Donald , Kells James J.
Published: May 2019

The antidotes dichlormid, MON-4660, CGA-154281, R-29148, and MON-13900 were tested in the greenhouse to protectZea maysL. (corn) against RPA 201772 injury. High rates of RPA 201772 injured four Z.mayshybrids > 30%. R-29148 and MON-13900 were the most effective of the five antidotes evaluated. R-29148 applied at rates ⩾ 45 g ha−1provided excellent protection against RPA 201772 injury and also prevented injury toZ. maysfrom diketonitrile, the active metabolite of RPA 201772. In laboratory studies, R-29148 did not alter absorption of14C-RPA 201772 from soil; however, R-29148 significantly enhanced the rate of RPA 201772 metabolism and inactivation inZ. mays.The mixed function oxidase inhibitor piperonyl butoxide (PBO) increased RPA 201772 injury on all hybrids. These results demonstrate thatZ. maystolerance to RPA 201772 can be enhanced with the use of antidotes such as R-29148 and MON-13900, that R-29148 protectsZ. maysfrom RPA 201772 and diketonitrile by the enhancement of metabolism, and that oxidative reactions may be involved in the metabolism of RPA 201772 inZ. mays.
Determination of allelochemicals in spring cereal cultivars of different competitiveness
Authors: Baghestani Ali , Lemieux Claudel , Leroux Gilles D. , Baziramakenga Regis , Simard Regis R.
Published: May 2019

Competitive cereal cultivars are less susceptible than others to weed interference. Their characterization may provide selection criteria that can be used as guidelines to develop new, even more competitive cultivars. Root exudates are a potential means by which competitive cultivars reduce weed growth. The objectives of this study were to evaluate the effect of cereal root exudates onBrassica kaber(DC.) L. C. Wheeler growth, to isolate and characterize the allelochemical compounds released by spring cereal cultivars, and to determine if a relation exists between these allelochemicals and cultivar competitiveness. Highly competitive (HC) and lesser competitive (LC) cultivars of four crop kinds (Triticum aestivumL. [wheat],Avena sativaL. [wild oat], two- and six-rowedHordeum vulgareL. [barley]) were selected based on previous work. Exudates from undisturbed root systems ofB. kaberand cereals were collected and used in a bioassay test withB. kaber.Root exudates were analyzed for 16 common phenolic compounds using high-performance liquid chromatography (HPLC). Bioassays indicated that cereal exudates had no negative effect onB. kabergermination, but all concentrations of cereal root exudates inhibitedB. kaberroot and hypocotyl growth. As cereal root exudate concentration increased,B. kabergrowth decreased. For each crop kind,B. kabergrowth inhibition was greater with HC cultivars than with LC cultivars. The root exudates of all crop kinds and cultivars contained benzoic, caffeic, ferulic,o-coumaric, and vanillic acids as well as scopoletin. Para-hydroxybenzoic acid was found in exudates fromT. aestivum, A. sativa, and two-rowedH. vulgarecultivars. Para-coumaric acid was not identified in root exudates from LCH. vulgarecultivars. Gentisic acid was produced byA. sativaandH. vulgare.Vanillic ando-coumaric acids along with scopoletin may be responsible for the allelopathic effects ofH. vulgare, T. aestivum, andA. sativacultivars. These three compounds may be useful as possible indicators of allelopathic potential of genotypes under development and thus considered for use in breeding programs.
Weed population dynamics in land removed from the conservation reserve program
Authors: Felix Joel , Owen Micheal D. K.
Published: May 2019

A field study was established in southern Iowa in 1994 to study seasonal and long-term weed population dynamics on land being brought back into production after 8 yr as part of the conservation reserve program (CRP). The study was a split-plot design with four replications; two tillage regimes, two crop rotations, and three herbicide application methods were used. Even though the tillage regime did not influence individual weed population density throughout the study, the no-till (NT) regime had more weeds compared to conventional tillage (CT). However, when weeds were grouped into categories, tillage influenced broadleaf weeds in 1994 and 1996 and total weeds in 1995. Plots under the NT regime had an average of 46 broadleaf weeds m−2compared to 27 in CT in 1994, withAmaranthus rudisSauer (common waterhemp) being the most prevalent. NT had a total of 186 weeds m−2compared to 125 m−2weeds in CT in 1995; however, in 1996, CT plots had 184 weeds m−2compared to 121 m−2in the NT regime. Except for broadleaf weeds in 1994, crop rotation did not influence the number of weeds, and herbicide application methods had the greatest effect on weed populations. Overall, weed populations were greater in 1997, 1996, and 1995 than in 1994 for all herbicide application methods. The no-herbicide treatment had the highest number of weeds throughout the study. The total number of weeds in band and broadcast treatments averaged 41 and 26 m−2in 1994; 96 and 24 m−2in 1995; 96 and 12 m−2in 1996; and 109 and 95 m−2in 1997. The use of broadcast herbicides in NT should be recommended for land coming out of CRP. Regardless of the herbicide application method or crop rotation, CT plots had better yields for bothZea maysL. (corn) andGlycine maxL. (soybean).Glycine maxhad a better stand compared toZ. maysin the first year, indicating that a rotation starting withG. maxmight be preferred in the land coming out of CRP.
Apocynum cannabinumseed germination and vegetative shoot emergence
Authors: Webster Theodore M. , Cardina John
Published: May 2019

Apocynum cannabinumis a native creeping perennial distributed throughout the U.S., with increasing importance in reduced tillage systems throughout the Midwest.Apocynum cannabinumhas been shown to be a difficult species to control in field crops. Effective weed management is often a function of the timing of control practice. Knowledge of weed emergence patterns may be useful in predicting the optimum time of weed management. The objectives of these studies were to describe how temperature and moisture affectA. cannabinumseed germination and to describe the relationship between growing degree units (GDU) andA. cannabinumvegetative shoot emergence. At constant temperatures, seed germination was described as a sigmoidal function of temperature (r2= 0.83), with maximum germination (32%) from 26 to 34 C. Under alternating temperatures, seed germination increased in a linear relationship between mean temperatures of 15 and 34 C (r2= 0.85). Maximum seed germination (88%) occurred at a mean temperature of 34 C under alternating temperatures. The relationship between seed germination and osmotic potential between −1.0 and 0 MPa was described by a gompertz function (r2= 0.98). Germination at −1.0 MPa was 4% and increased in a near linear manner to the nontreated control (0 MPa), which had 80% germination. Vegetative shoot emergence in 1997 and 1998 had a sigmoidal relationship to GDU using a base temperature of 6 C (r2= 0.96). However, initial shoot appearance was not consistent over years, with first emergence recorded on May 21, 1997 (132 GDU), and May 5, 1998 (73 GDU). Approximately 50% of the shoots emerged before June 7, 1997 (282 GDU), and May 21, 1998 (285 GDU); therefore, optimal weed management programs will need to be initiated following this GDU accumulation.
Site-to-site and year-to-year variation inTriticum aestivum–Aegilops cylindricainterference relationships
Authors: Jasieniuk Marie , Maxwell Bruce D. , Anderson Randy L. , Evans John O. , Lyon Drew J. , Miller Stephen D. , Morishita Don W. , Ogg Alex G. , Seefeldt Steven , Stahlman Phillip W. , Northam Francis E. , Westra Philip , Kebede Zewdu , Wicks Gail A.
Published: May 2019

Crop yield loss–weed density relationships critically influence calculation of economic thresholds and the resulting management recommendations made by a bioeconomic model. To examine site-to-site and year-to-year variation in winterTriticum aestivumL. (winter wheat)–Aegilops cylindricaHost. (jointed goatgrass) interference relationships, the rectangular hyperbolic yield loss function was fit to data sets from multiyear field experiments conducted at Colorado, Idaho, Kansas, Montana, Nebraska, Utah, Washington, and Wyoming. The model was fit to three measures ofA. cylindricadensity: fall seedling, spring seedling, and reproductive tiller densities. Two parameters:i, the slope of the yield loss curve asA. cylindricadensity approaches zero, anda, the maximum percentage yield loss asA. cylindricadensity becomes very large, were estimated for each data set using nonlinear regression. Fit of the model to the data was better using spring seedling densities than fall seedling densities, but it was similar for spring seedling and reproductive tiller densities based on the residual mean square (RMS) values. Yield loss functions were less variable among years within a site than among sites for all measures of weed density. For the one site where year-to-year variation was observed (Archer, WY), parameteravaried significantly among years, but parameteridid not. Yield loss functions differed significantly among sites for 7 of 10 comparisons. Site-to-site statistical differences were generally due to variation in estimates of parameteri.Site-to-site and year-to-year variation in winterT. aestivum–A. cylindricayield loss parameter estimates indicated that management recommendations made by a bioeconomic model cannot be based on a single yield loss function with the same parameter values for the winterT. aestivum-producing region. The predictive ability of a bioeconomic model is likely to be improved when yield loss functions incorporating time of emergence and crop density are built into the model's structure.
Effect of tillage andZea maysonChenopodium albumseedling emergence and density
Authors: Roman Erivelton S. , Murphy Stephen D. , Swanton Clarence J.
Published: May 2019

We studied the effect of tillage systems (no-till, chisel, and moldboard plow) and the presence or absence ofZea maysL. (corn) on soil temperature, moisture, and, subsequently, the emergence phenology and density ofChenopodium albumL. (common lambsquarters) at two sites (Elora and Woodstock) from 1993 to 1995. The tillage system affected the phenology ofC. albumseedling emergence only in 1995. In that year, more days were required to reach 80% cumulative seedling emergence in no-till than in the chisel or moldboard plow treatments. The delay in obtaining 80% cumulative emergence was attributed to a dry period from days 159 to 177 at Elora and from days 155 and 176 at Woodstock. The presence or absence of Z.maysdid not affect soil temperatures, soil moisture, orC. albumseedling emergence phenologies.Chenopodium albumseedling density was influenced by tillage and environmental conditions. Large variations in seedling density were attributed to environmental conditions. The presence or absence ofZ. maysdid not affectC. albumseedling density.
Pros and cons of pet ownership in sustaining independence in community-dwelling older adults: a scoping review
Authors: Obradović Nataša , Lagueux Émilie , Michaud Frédéric , Provencher Véronique
Published: May 2019

Although community services support ageing-in-place, older adults often report feelings of loneliness and social isolation. Unmet emotional needs are associated with poorer health, reduced functional abilities and increased mortality in this population. Pet ownership is an avenue worth exploring to reduce these adverse outcomes. This scoping review maps main findings and identifies key gaps with respect to the pros and cons of pet ownership in community-dwelling older adults pertaining to psycho-social, physical and functional outcomes. Scientific and grey literature published from January 2000 to July 2018 was searched. Data selection and extraction were performed by the first author and a sub-sample was co-validated by two co-authors. A total of 62 sources were included for descriptive and thematic analysis. A variety of pros (increased physical activity, wellbeing) and cons (grief, risk of falls) pertaining to psycho-social and physical outcomes were identified. Not many functional outcomes (support for daily routines) were mentioned, and few studies explored the simultaneous balance between the pros and cons of pet care. Further research exploring both clinicians’ and older pet owners’ perspectives is needed to deepen our understanding of the importance of considering companion animals in older adults’ daily lives and to strike a balance between perceived risks and benefits.
POLITICAL CORRUPTION AS A RELATIONAL INJUSTICE
Authors: Ceva Emanuela
Published: May 2019

The corruption of public officials and institutions is generally regarded as wrong. But in what exactly does this form of corruption consist and what kind of wrong does it imply? Recent proponents of the “institutionalist approach” to political corruption have concentrated on those occasions when incentive structures distract institutions from their essential purpose and weaken public trust. The corruption of individual public officials has been less relevant to their work, except for when it leads to the erosion of the functioning of institutions. From this perspective, a clear emphasis has been put on the consequences of corruption. In contrast, I argue that political corruption, whether individual or institutional, can be more fundamentally understood as a form of political injustice in which someone has violated the logic of mutual accountability that undergirds all relations of justice in rights-based systems. In this sense, political corruption occurs when public officials use their entrusted power of office for the pursuit of an agenda whose rationale may not be vindicated as coherent with the terms of their mandate. By focusing on the inherent qualities of corrupt political relations, I lay out a novel relational and deontological understanding of the inherent wrongness of political corruption as a form of unaccountable action.
CORRUPTION, CHARACTER, AND INSTITUTIONS
Authors: Villarreal-Diaz Mario
Published: May 2019

Is corruption merely a flaw of character, or is it more fundamentally related to the institutional environment? Scholars from various disciplines mainly side with the narrative that, ultimately, corruption is a problem of character flaws. Policy prescriptions around the world are designed based on this understanding. In this essay, I challenge this understanding, arguing that it is at best incomplete, and misleading at worst. I argue that we should focus instead on three aspects of how the prevalence of virtuous acts is profoundly tied to people’s institutional environment and the incentive structure that derives from it. First, I observe that there is a difference between virtue and acting virtuously, and that even with the aid of moral education and coercion, virtue itself is hard to come by. Second, I discuss how formal institutions and social norms influence people’s propensity to perform virtuous acts rather than engage in corruption. Finally, I explore how institutions that increase the transaction costs associated with everyday life also increase the prevalence of corruption. Based on these three explorations I derive some public policy guidelines that, if followed, might increase the probability of success of anticorruption programs.
THE CORRUPTION OF THE RULE OF LAW
Authors: Hasnas John
Published: May 2019

The corruption of the rule of law is an ambiguous phrase. It can refer either to the corruption of the value of the rule of law or to the corrupting effect that the commitment to the rule of law produces. This essay explains how both can be the case. The rule of law is one of a cluster of values that liberal political theory requires a morally legitimate government to exemplify. Thus, the rule of law is a component part of a just political structure. However, the phrase "the rule of law" is often used colloquially to refer to most or all of the cluster of liberal values. When used in this way, a duty to obey the law often attaches itself to the concept of the rule of law. It is the association of this duty with the concept of the rule of law when used in its narrow, literal sense to refer to only one of the liberal values that corrupts both those who are committed to the rule of law and the respect for the value itself.