bluuebunny/crossref_metadata_2025 huggingface dataset:
Biological Herbicides: Discovery, Development, Deployment
Authors: Templeton George E.
Published: May 2019

Chemical herbicides are without question the most effective immediate solution to most weed problems. They are not, however, the only option or necessarily the best for all weed control situations (23, 24, 34). Recent commercialization of two biological herbicides illustrates another weed control technology with potential (24, 27, 44, 50). Abbott Laboratories marketed the fungusPhytophthora palmivoraButler in 1981 for control of strangler vine (Morrenia odorataLindl.) in Florida citrus groves. The Upjohn Company will market the fungus (Colletotrichum gloeosporioidesf. sp.aeschynomene(c.g.a.) in 1982 for control of northern jointvetch [Aeschynomene virginica(L.) B.S.P.] in Arkansas rice (Oryza sativaL.) and soybean [Glycine max(L.) Merr.] fields (45).
Control of Waterhyacinth (Eichhornia crassipes) withNeochetina eichhorniae(Coleoptera: Curculionidae) and a Growth Retardant
Authors: Center Ted D. , Steward Kerry K. , Bruner Marc C.
Published: May 2019

Waterhyacinth [Eichhornia crassipes(Mart.) Solms] grown in screen-enclosed, outdoor aquaria were treated with factorial combinations of 0, 0.75, 1.5, or 3 kg/ha of the experimental growth retardant EL-509 [α-(4-chlorophenyl)-α-(1-methylethyl)-5-pyrimidine-methanol] and zero, one, two, or three pairs of waterhyacinth weevils (Neochetina eichhorniaeWarner)/plant, with three replicates of each weevil-number by retardant level combination. When plant growth was evaluated over a time course, significant effects of weevils and retardant were observed. After 127 days, however, waterhyacinth was reduced as weevil numbers increased, but the growth retardant was ineffective without weevils. Weevils appeared to be more effective when used in combination with the retardant, and the combined effects were additive.
Chemical and Cultural Methods for Bermudagrass (Cynodon dactylon) Control in Cotton (Gossypium hirsutum)
Authors: Frans Robert , McClelland Marilyn , Kennedy Sandra
Published: May 2019

A field study was conducted to develop systems using cultural and chemical methods for control of bermudagrass (Cynodon dactylonL.) in cotton (Gossypium hirsutumL.). Several control options were promising. On areas prepared either with a moldboard plow or a disk, the sodium and magnesium salts of dalapon (2,2-dichloropropionic acid) at 4.7 kg/ha directed to 25-cm-high cotton and repeated at the 40-cm height or the ethyl ester of difenopenten {4-[4-[4-(trifluoromethyl)phenoxy] phenoxy]-2-pentenoic acid} directed to 15-cm-high cotton and repeated at the 30-cm height, with either standard or close cultivation as needed, provided good bermudagrass control. On areas prepared with a moldboard plow, the isopropyl amine salt of glyphosate [N-(phosphonomethyl)glycine] at 4.4 kg/ha over-the-top as a fall application with cultivation as needed was promising.
Competition of Common Cocklebur (Xanthium pensylvanicum) with Soybean (Glycine max)
Authors: Bloomberg James R. , Kirkpatrick Bruce L. , Wax Loyd M.
Published: May 2019

The effects of common cocklebur (Xanthium pensylvanicumWallr.) on soybean [Glycine max(L.) Merr. ‘Wells′] development and seed yield were investigated at Urbana, Illinois, from 1974 through 1977. Increased densities of common cocklebur reduced soybean seed yield, total dry weight, and number of pods per plant. Under full-season competition, one common cocklebur/3 m of row reduced soybean seed yield by 3 to 12%. Soybean seed yield, total dry weight, and number of pods per plant increased as the length of time from soybean emergence to common cocklebur emergence increased. Common cocklebur emerging 4 weeks after soybean emergence reduced soybean seed yield by 7%. As duration of competition with common cocklebur increased, soybean seed yield, total dry weight, and number of pods per plant decreased. The reduction in soybean seed yield was less than 10% when common cocklebur was removed 6 weeks after soybean emergence. Effects of common cocklebur competition with soybeans in Illinois were similar to those observed in the southern United States.
Sunflower (Helianthus annum) and Velvetleaf (Abutilon theophrasti) Interference in Sugarbeets (Beta vulgaris)
Authors: Schweizer Edward E. , Bridge Larry D.
Published: May 2019

Intraspecific interference of populations of sunflower (Helianthus annuusL.) and velvetleaf (Abutilon theophrastiMedic), as well as interspecific populations of these two broadleaf weeds, in sugarbeets (Beta vulgarisL. ‘Mono Hy D2′) was determined in 2-yr field experiments. Sunflower was more competitive in sugarbeets than was velvetleaf. At densities of 6, 12, 18, and 24 sunflower plants/30 m of row, root yields were reduced 40, 52, 67, and 73%, respectively. At the same densities of velvetleaf, root yields were reduced only 14, 17, 25, and 30%, respectively. Interspecific interference of these two broadleaf weeds at the same densities reduced root yields 19, 36, 43, and 56%, respectively. The minimum number of weeds required/30 m of row to reduce sugarbeet root yields was predicted to be 1 for sunflower, 9 to 12 for velvetleaf, and 2 to 7 for an equal population of sunflower and velvetleaf.
Efficacy of Acifluorfen on Broadleaf Weeds. Times and Methods for Application
Authors: Lee Steve D. , Oliver Lawrence R.
Published: May 2019

In field tests, common cocklebur (Xanthium pensylvanicumWallr.) was controlled at the one- and two-leaf stages with 0.3 kg/ha acifluorfen {5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid}. Four-leaf common cocklebur required 1.1 kg/ha for comparable control. Acifluorfen at 0.6 and 0.8 kg/ha controlled 96 and 90% of entireleaf morningglory [Ipomoea hederacea(L.) Jacq. var.integriuscula] atone- and two-leaf stages, respectively, but control was reduced as plants aged. Dark applications (2100 h) were more effective than those at sun-up (0600 h) or midday (1200 h) in control of hemp sesbania [Sesbania exaltata(Raf.) Cory], pitted morningglory (Ipomoea lacunosaL.), and smooth pigweed (Amaranthus hybridusL.). Hour of application had no significant influence on control of common cocklebur or prickly sida (Sida spinosaL.). An increase in surfactant (80% alkyl aryl polyoxyethylene glycols) concentration enhanced acifluorfen control of entireleaf morningglory and Texas gourd [Cucurbita texana(A.) Gray] at the 0.3-kg/ha rate applied 2 weeks after emergence. Soybean [Glycine max(L.) Merr.] injury was increased with the 1.1-kg/ha rate when surfactant concentration was increased from 0.5 to 0.75%. Increasing the spray volume increased pitted morningglory control but decreased hemp sesbania control. In the growth chamber, better control of pitted morningglory and common cocklebur was obtained at high (35 C day, 26 C night) than at low temperatures (27 C day, 18 C night) when plants were treated 1 week after emergence.
Relationship between Soil-Applied Pyrazon and Content in Soil Solution
Authors: Streibig J. C.
Published: May 2019

The relationship between pyrazon [5-amino-4-chloro-2-phenyl-3(2H)-pyridazinone] in soil solution and dosage was examined in two soils under slurry equilibrium conditions and at field water capacity. In a sandy soil, the partition coefficient, calculated from a regression analysis of soil water content on dosage applied, was similar under slurry conditions and at field water capacity, but in a loamy sand, high in organic matter, the partition coefficient was somewhat higher at field water capacity than the estimated 4.71 measured in a great excess of water. In the sandy soil, neither the partition coefficients under slurry conditions nor at field water capacity were significantly different from Freundlich'sk.Under slurry conditions in the loamy sand this difference was barely significant, whereas at field water capacity the estimated partition coefficient was significantly higher than Freundlich'sk.Soil water sampling at field water capacity a fortnight after the start of the experiment showed a considerable increase in partition coefficient compared with the first sampling after 2 days, and the relationship in a sandy soil showed a slight non-linear trend, but that of the loamy sand still appeared to be linear. A desorption experiment indicated that the recovery of soil-adsorbed pyrazon was almost complete.
Competition of Common Cocklebur (Xanthium pensylvanicum) with Cotton (Gossypium hirsutum)
Authors: Snipes Charles E. , Buchanan Gale A. , Street Joe E. , Mcguire John A.
Published: May 2019

To determine the competitiveness of common cocklebur (Xanthium pensylvanicumWallr.) with cotton (Gossypium hirsutumL. 'Stoneville 213′), experiments were conducted on a Lucedale fine sandy loam from 1978 through 1980. Common cocklebur dry weight increased with increasing density up to 16 plants/15 m of row. No further increase in dry matter occurred beyond this density. Regression analysis showed that common cocklebur produced an average of 342 kg/ha of dry weight for each plant per 15-m row. Seed-cotton yields decreased as weed density increased up to 16 common cocklebur plants/15 m of row. Regression equations revealed yield losses ranging from 72 to 115 kg/ha for hand-harvested seed cotton and 57 to 90 kg/ha for machine-harvested seed cotton for each common cocklebur plant/15 m of row. Cotton stem diameter and height were reduced by weed competition in the same manner as seed cotton yields, but reductions were not as pronounced, indicating that these parameters were not good indicators of common cocklebur competition.
Mobility of Herbicides in Soil Columns Under Saturated- and Unsaturated-Flow Conditions
Authors: Weber Jerome B. , Whitacre David M.
Published: May 2019

Under unsaturated-flow conditions, bromacil (5-bromo-3-sec-butyl-6-methyluracil) was considerably more mobile than buthidazole {3-[5-(1,1-dimethylethyl)-1,3,4-thiadiazol-2-yl]-4-hydroxyl-1-methyl-2-imidazolidinone}. Because of their high water solubilities, both herbicides were much more mobile than atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine), prometon [2,4-bis (isopropylamino)-6-methoxy-s-triazine], or diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea]. Under saturated-flow conditions, buthidazole was leached through Lakeland loamy sand in slightly greater amounts than tebuthiuron {N-[5-(1,1-dimethylethyl)-1,3,4-thiadiazol-2-yl]-N,N′-dimethylurea} or CN-10-3510 (formerly VEL 3510) {1-β,β-dimethoxyl-1-methyl-3-[5-(1,1-dimethylethyl)-1,3, 4-thiadiazol-2-yl] urea}. Distribution of the three herbicides in the leached soil was similar and relatively uniform. In Lakeland loamy sand, 30 times as much tebuthiuron was leached under saturated-flow conditions as under unsaturated-flow conditions. Intermittent saturated-unsaturated-flow conditions resulted in four times as much leaching of tebuthiuron as unsaturated flow alone. Only one-tenth as much tebuthiuron leached under intermittent saturated-unsaturated-flow conditions as under saturated-flow conditions. Tebuthiuron added to Lakeland soil and oven-dried was retained in significantly greater amounts than when added to moist Lakeland soil. Low amounts of tebuthiuron leached through Lakeland loamy sand, Portsmouth sandy loam, and Rains silt loam, but high amounts leached through Davidson clay. Greater amounts of the herbicide were retained in the surface zones of the three former soils, but the inverse was the case for the Davidson soil.
Characterization of Rapid Atrazine Absorption by Excised Velvetleaf (Abutilon theophrasti) Roots
Authors: Price Thomas P. , Balke Nelson E.
Published: May 2019

Atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] uptake from solution by excised velvetleaf (Abutilon theophrastiMedic.) root segments was studied. Initial atrazine absorption by 1-cm segments cut from the apical 5 cm of roots was rapid. Atrazine concentration in the tissue became equal to the external atrazine concentration by 30 min. Atrazine did not accumulate in the root tissue to concentrations above the external solution, and rapid efflux of atrazine occurred when the root segments were washed with atrazine-free solution. Atrazine absorption was linear over a range of external atrazine concentrations. Dinitrophenol and KCN increased atrazine absorption during the first 3 min of exposure to atrazine. Anoxia increased atrazine absorption but decreased K+uptake. Decreasing temperatures decreased atrazine absorption. Q10values for atrazine uptake were between 1.3 and 1.4. The response of atrazine absorption by the excised roots to inhibitors, anoxia, external atrazine concentration, and temperature indicated simple diffusion as the mechanism of absorption of atrazine by velvetleaf roots.
Guidelines for Introducing Foreign Organisms into the United States for Biological Control of Weeds
Authors: Klingman Dayton L. , Coulson Jack R.
Published: May 2019

Research on biological control of weeds in the United States began early in this century with the use of introduced insects to control the weed, lantana (Lantana camara L.), in Hawaii. The highly successful program for biological control of St. Johnswort (sometimes called “Klamath weed”) (Hypericum perforatum L.) in California by the use of introduced insects in the 1940's and 1950's caused increased interest in this approach to weed control. As a result of this increased interest, the United States Department of Agriculture (USDA) established two overseas laboratories to study arthropod natural enemies of a number of weeds that had been introduced into the United States – in Rome, Italy, in 1959; and near Buenos Aires, Argentina, in 1962. The recent and successful use of an introduced rust pathogen (Puccinia chondrillina Bubak & Syd.) to control rush skeletonweed (Chondrilla juncea L.) in Australia, and the production and utilization of pathogens for control of weeds in the United States, has spurred further interest in biological control.
Fluometuron in Soil Solution as an Indicator of Its Efficacy in Three Soils
Authors: Patterson Michael G. , Buchanan Gale A. , Walker Robert H. , Patterson Richard M.
Published: May 2019

Analysis of fluometuron [1,1-dimethyl-3-(α,α,α-trifluoro-m-tolyl)urea] in soil solution after application of 0.5 or 1.0 ppmw revealed up to five-fold differences among three Alabama soils (Lucedale fine sandy loam, Decatur silty clay loam, and Sacul loam). Differences in fluometuron in soil solution were attributed to variable organic matter present and clay fractions. Fluometuron concentration in soil solution for each soil correlated well with control of four broadleaf weed species in a field experiment.
The Effect of Parentage on the Control of Volunteer Corn (Zea mays) in Soybeans (Glycine max)
Authors: Andersen Robert N. , Geadelmann Jon L.
Published: May 2019

Corn (Zea maysL.) in soybeans [Glycine max(L.) Merr.] currently can be controlled with either glyphosate [N-(phosphonomethyl)glycine] applied to corn that is taller than soybeans, or diclofop {2-[4-(2,4-dichlorophenoxy)phenoxy] propanoic acid} sprayed over-the-top of both corn and soybeans. We found a wide range in tolerance to over-the-top spray applications of glyphosate among 240 F2hybrids of corn. Glyphosate was then applied with a rope-wick to one tolerant and one susceptible F2corn hybrid growing in soybeans. In only two instances out of six (three stages of growth times 2 yr), the susceptible corn was controlled better than the tolerant corn; but, in these two instances, the better control was not reflected in greater soybean yields. In another experiment, one F2corn hybrid identified (in a previous study) as tolerant of diclofop and one identified as susceptible were sprayed in soybeans with over-the-top diclofop treatments. In 11 instances out of 12 (two stages of growth times three rates times 2 yr), the susceptible corn was controlled better than the tolerant corn, and in nine of these instances, the better control was reflected in greater soybean yields. Corn parentage could be important in determining the degree of control obtained with either herbicide, but this is more likely with diclofop than with glyphosate.
Effect of Three Dinitroaniline Herbicides on Rice (Oryza sativa) Growth
Authors: Brewer Fayte , Lavy Terry L. , Talbert Ronald E.
Published: May 2019

A field study was conducted for 3 yr to evaluate residual levels of fluchloralin [N-(2-chloroethyl)-2,6-dinitro-N-propyl-4-(trifluoromethyl)aniline], profluralin [N-(cyclopropylmethyl)-α,α,α-trifluoro-2,6-dinitro-N-propyl-p-toluidine], and trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) for their effects on injury and yields of rice (Oryza sativaL.). All three herbicides consistently injured rice and reduced yield at application rates above 0.1 kg/ha. These herbicides were similar in their effects on rice, but trifluralin was slightly more phytotoxic than fluchloralin or profluralin. Bioassay showed fluchloralin and trifluralin to be more inhibitory than profluralin of root and shoot elongation. The order of toxicity of the vapors of these herbicides arising from treated soil was found to be trifluralin > profluralin > fluchloralin. Grain sorghum (Sorghum bicolorL. Moench) was slightly more sensitive to these herbicides than was rice when seedlings were grown in treated soil and over 10 times more susceptible than rice to injury from their vapors. Both plant species were less affected by the herbicides in silty clay than in silt loam soil.
The Influence of Straw Mulch on the Soil Reception and Persistence of Metribuzin
Authors: Banks Philip A. , Robinson Edward L.
Published: May 2019

The presence of a straw mulch on the soil surface did not significantly affect the persistence of metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazin-5 (4H)-one] in the soil. The half-life of metribuzin was 5.3 days in 1979 and 12.5 days in 1980 in the field when the time the herbicide was exposed on the soil and straw surface prior to rainfall or irrigation was 10 and 0 days, respectively. The half-life of metribuzin was 17.1 days in the greenhouse where soil temperature was lower and leaching, volatilization, and photodegradation losses were less than in the field. Increasing the amount of straw on the soil surface greatly decreased the initial soil reception of metribuzin as well as the amount of metribuzin that was subsequently washed off the straw by water. Less than 45% of the applied metribuzin reached the soil surface when 2250 kg/ha of straw was present and 0.3 cm or more of water was applied.
The Influence of Temperature, Moisture, and Prior EPTC Application on the Degradation of EPTC in Soils
Authors: Obrigawitch Tim , Wilson Robert G. , Martin Alex R. , Roeth Fred W.
Published: May 2019

Laboratory and field studies were conducted to compare the degradation rate of EPTC (S-ethyl dipropylthiocarbamate) in soils with a previous history of EPTC application vs. soils with no prior EPTC application. Laboratory experiments showed a rapid breakdown of14C-carbonyl EPTC to14CO2in Kennebec silt loam (sil) and Tripp very fine sandy loam (vfsl) with prior exposure to EPTC. A single prior application of EPTC to Tripp vfsl was sufficient to increase the rate of14CO2evolution. The rate of EPTC degradation in Tripp vfsl with a history of EPTC exposure was dependent on soil moisture from below 3% and independent of moisture above 3%. Patterns of degradation at 5, 15, and 25 C in the Kennebec sil with and without prior history were described by exponential decay. EPTC was degraded more rapidly at 15 and 25 C in the Kennebec sil with a prior EPTC history. Under field conditions the breakdown of EPTC in a Kennebec sil with and without prior exposure to EPTC was similar to laboratory results.
Common Lambsquarters (Chenopodium album) Interference in Sugarbeets (Beta vulgaris)
Authors: Schweizer Edward E.
Published: May 2019

Interference of common lambsquarters (Chenopodium albumL.) in sugarbeets (Beta vulgarisL. ‘Mono Hy D2′) was determined in a 2-yr field experiment. Yield of sugarbeet roots and recoverable sucrose/ha decreased as the density of common lambsquarters increased. At densities of 6, 12, 18, and 24 common lambsquarters plants/30 m of row, root yields were reduced 13, 29, 38, and 48%, respectively, and recoverable sucrose yields were reduced 11, 27, 37, and 46%, respectively. The minimum number of common lambsquarters plants required per 30 m of row to reduce sugarbeet root yields was estimated to be six in 1980 and four in 1981.
Fractionation of Residues of Pendimethalin, Trifluralin, and Oryzalin during Degradation in Soil
Authors: Nelson James E. , Meggitt William F. , Penner Donald
Published: May 2019

A sequential extraction procedure was developed to study the fate of pendimethalin [N- (1 -ethylpropyl) -3,4- dimethyl - 2,6 - dinitrobenzenamine], trifluralin (α,α,α -trifluoro - 2,6 - dinitro -N,N- dipropyl -p- toluidine), and oryzalin (3,5 -dinitro-N4,N4-dipropylsulfanilamide) in soil over a 6 - month laboratory incubation period. The distinction of non - bound residues was based on an acidic - methanol extraction followed by an extraction with an acetone :H2O : HCl (95:4:1, v/v/v) solution and then extraction with 0.5 N NaOH with further fractionation of the NaOH extract by partial precipitation. After 6 months, soil - bound14C-residues of pendimethalin, trifluralin, and oryzalin contained 15, 14, and 23%, respectively, of the radioactivity applied to non - sterilized soil. The proportion of bound radioactivity associated with each organic fraction was nearly identical for each herbicide; 46, 12, 12, and 30% was associated with the acetone:H2O:HCl-soluble, fulvic acid, humic acid, and humin organic fractions, respectively. Soil sterilization reduced herbicide degradation by 31% and radioactivity in the fulvic acid, humic acid, and humin organic fractions by approximately 50% during the 6-month period. Radioactivity in the acetone:H2O:HC1-soluble fraction was reduced less than 10% by soil sterilization.
Influence of Norflurazon on the Activation of Substituted Diphenylether Herbicides by Light
Authors: Devlin Robert M. , Karczmarczyk Stanislaw J. , Zbiec Irena I.
Published: May 2019

Oxyfluorfen [2 - chloro -1 - (3 - ethoxy - 4 - nitrophenoxy) -4 - (trifluoromethyl)benzene] and RH-8817 {ethyl 5 - [2-chloro - 4 -{trifluoromethyl) phenoxy] - 2 - nitrobenzoate} require light for activation. Removal of carotenoids by treating corn (Zea maysL.) seedlings with norflurazon [4 - chloro - 5 - (methylamino) - 2 - (α, α, α - trifluoro -m- tolyl) - 3 (2H) - pyridazinone] rendered them partially tolerant of oxyfluorfen and RH-8817 even when grown in the light. The activation of substituted diphenylether herbicides may occur as a result of the absorption of light energy by carotenoids.
Competition of Bearded Sprangletop (Leptochloa fascicularis) with Rice (Oryza sativa)
Authors: Smith Roy J.
Published: May 2019

Yields of drill-seeded paddy rice (Oryza sativaL. ‘Lebonnet’) at optimum stands of 215 to 270 plants/m2at Stuttgart, Arkansas, were reduced 9, 18, 20, and 36% by bearded sprangletop [Leptochloa fascicularis(Lam.) Gray] densities of 11, 22, 54, and 108 plants/m2, respectively. There was a linear decrease in rice grain yield of 21 kg/ha for each bearded sprangletop plant per square meter. Weed densities of 54 and 108 plants/m2reduced head-rice yields (whole milled kernels) and a density of 108 plants/m2reduced germination of rice seed. The number of bearded sprangletop panicles produced per weed plant decreased as the weed density increased.
Effect of Spray Components on Glyphosate Toxicity to Annual Grasses
Authors: Buhler Douglas D. , Burnside Orvin C.
Published: May 2019

Field and greenhouse research was conducted during 1980 and 1981 to evaluate the effects of carrier volume, surfactant concentration, and treatment date on glyphosate [N- (phosphonomethyl)glycine] toxicity to annual-grass weeds and volunteer small grains. Glyphosate phytotoxicity increased as carrier volume was decreased from 190 to 24 L/ha. The presence of a surfactant in the spray solution did not influence grass control when glyphosate was applied in a carrier volume of 24 L/ha. When glyphosate was applied in 48 or 95 L/ha, the presence of surfactant resulted in better grass control than glyphosate without surfactant. When applied in 190 L/ha, glyphosate with 0.5% (v/v) surfactant gave better grass control than glyphosate alone or commercially formulated glyphosate. When glyphosate was applied to plants under water stress, little control was achieved regardless of plant growth stage. Glyphosate application to grass after head initiation also resulted in reduced control. Maximum weed control with glyphosate was attained when applications were made to seedlings growing actively because of adequate soil moisture and favorable temperatures.
Interference and Temperature Effects on Growth in Soybean (Glycine max) and Associated C3and C4Weeds
Authors: Flint Elizabeth P. , Patterson David T.
Published: May 2019

Effects of temperature and interference were examined in a replacement series experiment with soybean [Glycine max(L.) Merr. ‘Ransom’], common cocklebur (Xanthium pensylvanicumWallr.), and smooth pigweed (Amaranthus hybridusL.). Plants were grown in controlled-environment greenhouses at day/night temperatures of 32/23, 29/20, or 26/17C and harvested 14 and 34 days after planting. In all species, height, dry weight, and leaf area at both harvests, and dry matter and leaf area duration for the harvest interval, increased significantly with temperature. Net assimilation rate in all species peaked at 29/20C. Dry weight and leaf area at day 34, and dry matter production and leaf area duration for the harvest interval, were reduced in plants subjected to interference. Temperature modified the effects of interference upon growth in smooth pigweed, but not in the other species. Common cocklebur and soybean were roughly equivalent as competitors at all temperatures and were superior to smooth pigweed.
Effect of Moisture Stress on Wild Oat (Avena fatua) Response to Diclofop
Authors: Akey William C. , Morrison Ian N.
Published: May 2019

The effect of moderate moisture stress on the activity of the methyl ester of diclofop {2-[4-(2,4-dichlorophenoxy)phenoxy] propanoic acid} applied to wild oat (Avena fatuaL.) and the influence of morphological and physiological factors on the activity of the herbicide on stressed plants were investigated in growth-room experiments. Wild oat was grown in very fine sandy loam brought to a gravimetric soil moisture content (SMC) of 20% (water potential of -0.3 bars) or 10% (-6.5 bars) prior to herbicide treatment. The activity of diclofop on wild oat was slightly, but significantly, reduced when the SMC was increased from 10 to 20% immediately after spraying. Maintaining the SMC at 10% after spraying further reduced the activity of the herbicide. Wild oat plants grown at 20% SMC had 22% greater leaf area and retained 23% more herbicide than plants grown at 10% SMC. Penetration of the methyl ester of14C-diclofop into wild oat grown at 20 or 10% SMC did not differ significantly 12, 24, or 48 h after application. Stressed and unstressed plants did not differ significantly in the metabolism of the methyl ester of14C-diclofop. However, growth at a low SMC prior to treatment decreased the proportion of the radiolabeled herbicide recovered in the apex, third leaf, and tillers of wild oat. This may partially account for the reduced activity of this herbicide on wild oat subjected to moisture stress.
Weed-Control Evaluations in Ratoon-Cropped Grain Sorghum (Sorghum bicolor)
Authors: Banks Philip A. , Duncan Ronny R.
Published: May 2019

Weed-control evaluations in ratoon-cropped grain sorghum [Sorghum bicolor(L.) Moench.] indicated that acceptable broadleaf weed control (>80%) in the second crop could be achieved by the use of a contact herbicide plus a residual herbicide applied after first harvest. Annual grasses, especially volunteer grain sorghum, were controlled in the second crop with metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide] plus propazine [2-chloro-4,6-bis(isopropylamino)-s-triazine] applied preemergence at planting and followed by metolachlor, cyanazine {2-[[4-chloro-6-(ethylamino)-s-triazin-2-yl] amino]-2-methylpropionitrile}, or pendimethalin [N-(1-ethylpropyl)-3,4-dimethyl-2,6-dinitrobenzenamine] applied after first harvest. Second-crop grain yields were not adversely affected by any treatments, and it appeared that satisfactory weed control in the first crop lessened the need for a residual herbicide in the second crop.
Effect of Field Application of Growth Regulators on Secondary Dormancy of Common Ragweed (Ambrosia artemisiifolia) Seeds
Authors: Samimy Cyrus , Khan Anwar A.
Published: May 2019

Winter chilling in the field removed the primary dormancy in common ragweed (Ambrosia artemisiifoliaL.) seeds and allowed them to germinate in both light and darkness. A secondary dormancy was induced in the spring and seeds again failed to germinate in light or darkness. Kinetin (K) + ethephon (E) + gibberellin A4+ A7(GA4+7) applied to the soil in December prevented secondary dormancy. The following May only 20% of the seeds at the 15-cm depth remained viable. The rest had germinated or decayed. In contrast, 89% of the untreated seeds remained viable. Application of K + E + GA4+7on April 22 and May 2 also broke the secondary dormancy. Gibberellin A3 (GA3) was less effective than GA4+7in preventing or breaking secondary dormancy.
Effect of Soil PH on Fluridone Activity and Persistence as Determined by Chlorophyll Measurements
Authors: Shea Patrick J. , Weber Jerome B.
Published: May 2019

Residue levels of fluridone {1-methyl-3-phenyl-5-[3-(trifluoromethyl)phenyl]-4(1H)-pyridinone} in soil were determined indirectly by measuring the chlorophyll content of wheat (Triticum aestivumL.) grown on a Norfolk sandy loam (Typic paleudult; fine loam, siliceous, thermic) 14, 22, 39, and66days after a preemergence application of the herbicide. The half-life for 0.22 and 0.45 kg/ha of fluridone was estimated to be 18 days. Phytotoxicity increased with increasing pH in newly-treated soils and in soil sampled 14 days after treatment. Higher chlorophyll levels in wheat grown in soil sampled 39 days after fluridone application indicated a decrease in biologically-active herbicide. Soil removed from the field following later cultivation produced small reductions in chlorophyll at pH 4.0 and 5.2, but at pH 7.0 significant fluridone activity was still present in the soil after 66 days. Cultivation may have increased the surface concentration of the herbicide.
Leaf Water Potential of Weeds and Rice (Oryza sativa)
Authors: Cruz Rolando T. , O'Toole John C. , Moody Keith
Published: May 2019

Twenty days after rice (Oryza sativaL. ‘IR28’) emergence, water was withheld from the stress treatment for 20 days while the control was kept well-watered by furrow irrigation. In the control plots, rice leaf water potential at 0800 hours was –5.5 bars and leaf length 30 cm on the 12th day of stress. In the stress treatment, leaf water potential decreased to –8 bars and leaf length to 20 cm, when no weeds competed with rice. With maximum weed competition, rice leaf water potential decreased to –18 bars and leaf length to 15.5 cm. on the 20th day of stress, dawn (0600 h) leaf water potential of rice in the stress treatment was reduced from –8 bars when no weeds competed with rice to –19 bars when competition was maximum. The weed species had higher water potential values than the rice in both control and water-stress treatments.
VINCOLI STORICO-STRUTTURALI SULLA PRESTAZIONE DELLE BUROCRAZIE LEGALI-RAZIONALI
Authors: Freddi Giorgio
Published: May 2019

Introduzione

Nella letteratura sui sistemi demo-costituzionali moderni vi è generale consenso sul fatto che le burocrazie pubbliche, con personale amministrativo di carriera e professionalizzato, sono responsabili per la maggior parte delle iniziative politiche prese da organi politici quali l'esecutivo e il legislativo. «Dando per scontato che la burocrazia permanente svolge un ruolo decisivo nel processo di decisione politica, si pone al politologo un problema centrale: in che modo la burocrazia risponde ai bisogni sociali e alle domande politiche in continuo mutamento, e perché?».
LE TRASFORMAZIONI ORGANIZZATIVE NEI PARTITI POLITICI TEDESCHI
Authors: von Beyme Klaus
Published: May 2019

Introduzione

Nella prima metà del XX secolo, le teorie sui partiti politici hanno sottolineato il principio dell'organizzazione come crite-rio fondamentale in base al quale differenziare i partiti da più tradizionali gruppi d'influenza politica, quali fazioni, organizzazioni burocratiche, ceti o gruppi clientelari. Dal classico studio di Ostrogorski alle pagine sui partiti di Max Weber inEconomia e Società, i partiti moderni per eccellenza sono stati considerati quelli inglesi che avevano sviluppato leadership carismatiche, struttura organizzativa acaucuse capacità di mobilitazione elettorale di massa nelle circoscrizioni. Entrambi gli autori hanno rivolto la loro attenzione ai partiti consolidati, dato il loro interesse — oltre che per l'ideologia — per il fenomeno del «clientelismo» visto come strumento di integrazione. Entrambi hanno, invece, dato scarso rilievo al nuovo tipo di partito operaio di opposizione il cui potere era, a quel tempo, ancora abbastanza limitato.
GLI ISCRITTI AI PARTITI DI MASSA: ANALISI DELL'ESPERIENZA SOCIALISTA IN EUROPA (1889–1978)
Authors: Bartolini Stefano
Published: May 2019

Introduzione

Tra i più importanti contributi che gli studi sul comportamento elettorale hanno offerto alla comprensione delle società contemporanee vi è certamente il riconoscimento della complessità dei processi attraverso i quali la varietà dei ruoli sociali, culturali, economici e politici degli individui si traducono in scelte politiche ed elettorali. Non che la sociologia classica fosse inconsapevole di tali complessità; piuttosto, la moderna sociologia elettorale ha prodotto una tale massa di evidenza empirica da mettere in discussione anche i modelli più sofisticati e meno deterministici del rapporto tra struttura sociale e comportamento politico. Di conseguenza, si è rivalutata l'importanza ed il ruolo dei partiti e di altre istituzioni politiche nel processo che ha condotto alla strutturazione delle attuali principali fratture e allineamenti politici.
STATO E MOVIMENTI COLLETTIVI NEI PROCESSI RIVOLUZIONARI
Authors: Mattina Liborio
Published: May 2019

Introduzione

Solo negli anni più recenti il fenomeno della rivoluzione ha trovato nelle scienze sociali statunitensi una significativa collocazione teorica nel repertorio dei processi che trasformano il sistema sociale. Nei primi due decenni del secondo dopoguerra lo struttural-funzionalismo e la teoria del pluralismo democratico, in virtò dell'influenza decisiva esercitata fin nella definizione dei paradigmi della scienza politica e della sociologia nord-americana, hanno orientato gran parte della teoria e della ricerca a sottolineare gli elementi di stabilità e di equilibrio del sistema e a trascurare quelli di conflitto. Uno spartiacque analitico ha, perciò, rimarcato una netta discontinuità tra la violenza collettiva (e la rivoluzione quale sua forma estrema) e il conflitto istituzionalizzato che rientra nel novero delle normali relazioni sociali. Sulla scorta di questa implicita, e tuttavia operante distinzione, si è arrivati ad ipotizzare una sostanziale similarità tra le cause che generano i movimenti rivoluzionari e i fenomeni di panico, le manie, le improvvise esplosioni di ostilità. Apparentato al sorgere di questo tipo di comportamenti collettivi, il problema della genesi della rivoluzione è stato spesso affrontato con un approccio socio-psicologico considerato come il più adeguato sul piano concettuale a comprendere fenomeni collegati a tensioni non sempre razionali. Anche nei casi in cui, con stretta aderenza al paradigma funzionalista, la rivoluzione è stata interpretata come una disfunzione multipla e simultanea dei sottosistemi sociali, l'insorgere del fenomeno è stato comunque ridimensionato a degenerazione patologica di sistemi che élites politiche competenti e flessibili possono prevenire con riforme ed iniziative adeguate ad evitare la diffusione della violenza politica e dello squilibrio sociale.
Epidemiological state-building in interwar Poland: discourses and paper technologies
Authors: Kreuder-Sonnen Katharina
Published: May 2019

Argument

The paper argues that epidemic surveillance and state-building were closely interconnected in interwar Poland. Starting from the paper technology of weekly epidemiological reporting it discusses how the reporting scheme of Polish epidemics came into being in the context of a typhus epidemic in 1919–20. It then shows how the statistics regarding nation-wide epidemics was put into practice. It is only when we take into account these practices that we can understand the epidemiological order the statistics produced. The preprinted weekly report form registered Jews and Christians separately. Yet, the imagined national epidemiological space that emerged from it hardly took notice of this separation. Rather, the category that differentiated Polish epidemiological space in medical discourse was the capacity of contributing to the state-making practices of epidemic surveillance. This category divided Poland into two regions: a civilized and modern western region and a backward and peripheral eastern region.
Eugenics and racial anthropology in the Ukrainian radical nationalist tradition
Authors: Rudling Per Anders
Published: May 2019

Argument

Eugenics and race played significant roles in Ukrainian interwar nationalism, yet remain largely unstudied. The Ukrainian nationalists’ understanding of the racial makeup of their imagined community was contradictory as they struggled to reconcile their desire for racial “purity” with the realities of significant variations between the populations inhabiting the enormous territories which they sought to include in their intended state project. The “turn to the right” over the 1930s placed an increased onus on race, and eugenics came to occupy an increasingly prominent place in Ukrainian radical nationalism from around 1936. In 1941, the leading Ukrainian far-right organization, the OUN had developed a project for eugenic engineering, for their aborted state, declared in L’viv on June 30, 1941. Racial conceptualizations of the Ukrainian community figured prominently well into the Cold War era, gaining a new actuality and meaning in an émigré community dispersed across several countries.
The Reinvention of Vouchers for a Color-Blind Era: A Racial Orders Account
Authors: Hackett Ursula , King Desmond
Published: May 2019

Historically, vouchers, which provide a sum of money to parents for private education, were tools of racist oppression; but in recent decades some advocates claim them as “the civil rights issue of our time.” This article brings an analytic-historical perspective rooted in racial orders to understand how education vouchers have been reincarnated and reinvented since the Jim Crow era. Combining original primary research with statistical analysis, we identify multiple concurrent and consecutive transformations in voucher politics in three arenas of racial policy alliance contestation: expansion of color-blind policy designs, growing legal and political support from a conservative alliance, and a smorgasbord of voucher rationales rooted in color-blind framing. This approach demonstrates that education vouchers have never been racially neutral but served key roles with respect to prevailing racial hierarchies and contests.
Dietary acid load and cardiometabolic risk factors: a systematic review and meta-analysis of observational studies
Authors: Daneshzad Elnaz , Haghighatdoost Fahimeh , Azadbakht Leila
Published: May 2019

Objective:

Dietary acid load (DAL) might contribute to change the levels of cardiometabolic risk factors; however, the results are conflicting. The present review was conducted to determine the relationship between DAL and cardiometabolic risk factors.

Design:

Systematic review and meta-analysis.

Setting:

A systematic search was conducted in electronic databases including ISI Web of Science, PubMed/MEDLINE, Scopus and Google Scholar for observational studies which assessed cardiometabolic risk factors across DAL. Outcomes were lipid profile, glycaemic factors and anthropometric indices. Effect sizes were derived using a fixed- or random-effect model (DerSimonian–Laird). Also, subgroup analysis was performed to find the probable source of heterogeneity. Egger’s test was performed for finding any publication bias.

Results:

Thirty-one studies were included in the current review with overall sample size of 92 478. There was a significant relationship between systolic blood pressure (SBP; weighted mean difference (WMD) = 1·74 (95 % CI 0·25, 3·24) mmHg;P= 0·022;I2= 95·3 %), diastolic blood pressure (DBP; WMD = 0·75 (95 % CI 0·07, 1·42) mmHg;P= 0·030;I2= 80·8 %) and DAL in cross-sectional studies. Serum lipids, glycaemic parameters including fasting blood sugar, glycated Hb, serum insulin, homeostatic model assessment of insulin resistance and waist circumference had no significant relationship with DAL. No publication bias was found. BMI was not associated with DAL in both cross-sectional and cohort studies.

Conclusions:

Higher DAL is associated with increased SBP and DBP. More studies are needed to find any relationship of DAL with lipid profile and glycaemic factors.
Household food insecurity in Panamanian subsistence farming communities is associated with indicators of household wealth and constraints on food production
Authors: Krause Rachel J , Scott Marilyn E , Sinisterra Odalis , Koski Kristine G
Published: May 2019

Objective:

To determine if constraints on agricultural production were a novel construct in the Panama Food Security Questionnaire (FSQ) and to characterize agricultural and economic determinants of food insecurity during the planting, growing and harvesting time periods in subsistence farming communities.

Design:

This longitudinal study followed households during land preparation, growing and harvest periods in one agricultural cycle. Agricultural production and economic variables were recorded and the Panama FSQ was administered. Exploratory factor analysis was used to verify construct validity of the FSQ. A food insecurity score (FIS), ranging from 0 to 42, was derived. Multiple regression analyses of FIS were conducted for each agricultural period.

Setting:

Fifteen rural villages in Panama.

Participants:

Subsistence farming households (n 237).

Results:

The FSQ contained four constructs: (i) ability to buy food; (ii) decreased amount/number of meals; (iii) feeling hungry; and (iv) lower agricultural production because of weather or lack of resources. Although most households were mildly food insecure in all time periods, determinants of food insecurity differed in each. Higher FIS was associated during land preparation with less rice and legumes planted and lower asset-based wealth; during growing months with less rice, more maize and pigeon peas planted and not selling produce; and during harvest with less rice planted, fewer chickens and lower income.

Conclusions:

Constraints on agriculture was a novel construct of the Panama FSQ. Different income-related variables emerged in each agricultural period. Planting staple foods and raising chickens were associated with food security, but some crop choices were associated with food insecurity.
Heritability of Type 2 Diabetes in the Washington State Twin Registry
Authors: Avery Ally R. , Duncan Glen E.
Published: May 2019

Approximately 12% of U.S. adults have type 2 diabetes (T2D). Diagnosed T2D is caused by a combination of genetic and environmental factors including age and lifestyle. In adults 45 years and older, the Discordant Twin (DISCOTWIN) consortium of twin registries from Europe and Australia showed a moderate-to-high contribution of genetic factors of T2D with a pooled heritability of 72%. The purpose of this study was to investigate the contributions of genetic and environmental factors of T2D in twins 45 years and older in a U.S. twin cohort (Washington State Twin Registry, WSTR) and compare the estimates to the DISCOTWIN consortium. We also compared these estimates with twins under the age of 45. Data were obtained from 2692 monozygotic (MZ) and same-sex dizygotic (DZ) twin pairs over 45 and 4217 twin pairs under 45 who responded to the question ‘Has a doctor ever diagnosed you with (type 2) diabetes?’ Twin similarity was analyzed using both tetrachoric correlations and structural equation modeling. Overall, 9.4% of MZ and 14.7% of DZ twins over the age of 45 were discordant for T2D in the WSTR, compared to 5.1% of MZ and 8% of DZ twins in the DISCOTWIN consortium. Unlike the DISCOTWIN consortium in which heritability was 72%, heritability was only 52% in the WSTR. In twins under the age of 45, heritability did not contribute to the variance in T2D. In a U.S. sample of adult twins, environmental factors appear to be increasingly important in the development of T2D.
Quenching of Equatorial Magnetosonic Waves by Substorm Proton Injections
Authors: Dai Guyue , Su Zhenpeng , Liu Nigang , Wang Bin , Zheng Huinan , Wang Yuming , Wang Shui
Published: May 2019

Near equatorial (fast) magnetosonic waves, characterized by high magnetic compressibility, are whistler‐mode emissions destabilized by proton shell/ring distributions. In the past, substorm proton injections are widely known to intensify magnetosonic waves in the inner magnetosphere. Here we report the unexpected observations by the Van Allen Probes of the magnetosonic wave quenching associated with the substorm proton injections under both high‐ and low‐density conditions. The enhanced proton thermal pressure distorted the background magnetic field configuration and the cold plasma density distribution. The reduced phase velocities locally allowed the weak growth or even damping of magnetosonic waves. Meanwhile, the spatially irregularly varying refractive indices might suppress the cumulative growth of magnetosonic waves. For intense injections, this wave quenching region could extend over 2 hr in magnetic local time and 0.5 Earth radii in radial distance. These results provide a new understanding of the generation and distribution of magnetosonic waves.
Spatial Inhomogeneities in the Sedimentation of Biogenic Particles in Ocean Flows: Analysis in the Benguela Region
Authors: Monroy Pedro , Drótos Gabor , Hernández‐García Emilio , López Cristóbal
Published: May 2019

Sedimentation of particles in the ocean leads to inhomogeneous horizontal distributions at depth, even if the release process is homogeneous. We study this phenomenon considering a horizontal sheet of sinking particles immersed in an oceanic flow and determine how the particles are distributed when they sediment on the seabed (or are collected at a given depth). The study is performed from a Lagrangian viewpoint attending to the properties of the oceanic flow and the physical characteristics (size and density) of typical biogenic sinking particles. Two main processes determine the distribution, the stretching of the sheet caused by the flow, and its projection on the surface where particles accumulate. These mechanisms are checked, besides an analysis of their relative importance to produce inhomogeneities, with numerical experiments in the Benguela region. Faster (heavier or larger) sinking particles distribute more homogeneously than slower ones.