bluuebunny/crossref_metadata_2025 huggingface dataset:
Gastrointestinal helminths from the common warthog,Phacochoerus africanus(Gmelin) (Suidae), in KwaZulu-Natal Province, South Africa, with comments on helminths of Suidae and Tayassuidae worldwide
Authors: Junker Kerstin , Spickett Andrea , Swanepoel Monlee , Krasnov Boris R. , Boomker Joop , Hoffman Louwrens C.
Published: May 2019

Thirty warthogs,Phacochoerus africanus, were collected in the Pongola Game Reserve, South Africa and examined for helminths. Gastrointestinal helminth assemblages comprisedGastrodiscus aegyptiacus, the cestode genusMonieziaand seven species of nematodes. A single warthog harboured a metacestode ofTaenia hydatigenain the mesenteries. No helminths were found in the heart, lungs or liver of the warthogs.Probstmayria viviparaandMurshidiaspp. were the most prevalent as well as abundant helminth species, followed byPhysocephalus sexalatus. The incidence ofMonieziadid not differ between hosts of different sex or age. Numbers ofMurshidiaspp. were not affected by host sex, but were higher in adults than in juveniles. Conversely, burdens ofTrichostrongylus thomasiwere not affected by host age, but were higher in males than in females. While not highly significant, helminth assemblages in male warthogs were more species rich than in females. Helminth communities in the three genera of wild sub-Saharan suids are largely unique, butPh. africanusandHylochoerus meinertzhagenishare more worm species with each other than withPotamochoerus larvatus, possibly because the former two are more closely related. Overlap between helminth communities of African wild suids and those of other suids and Tayassuidae worldwide is limited.
Gas Exchange Properties of Jointed Goatgrass (Aegilops cylindrica)
Authors: Gealy David R.
Published: May 2019

Net (apparent) photosynthesis rate (Pn) of jointed goatgrass (Aegilops cylindricaHost # AEGCY) leaves in the greenhouse became light saturated at a photosynthetic photon flux density (PPFD) of about 1000 μE·m–1-2·s–1with a maximum Pn of 27 mg CO2·dm–2·h–1. Diffusive resistance to water vapor (rl) of adaxial leaf surfaces was 43% that of abaxial surfaces, in part, because stomatal density was 50% greater on adaxial leaf surfaces than on abaxial surfaces. Dark respiration rate (Rd) was 1.6 mg CO2·dm−2·h−1. Light compensation point (CPl) was 21 μE·m−2·s−1and CO2compensation point (CPc) was 32 ppmv. In the field, where light intensity and temperature were greater than in the greenhouse, leaves became light saturated for Pn at a higher intensity, and Rd and CPl were three times greater than in the greenhouse. Pn and Rd of spikes at anthesis were at least 30% less and 200% greater, respectively, than the values for leaves.
Growth and Development of False Cleavers (Galium spurium L.)
Authors: Malik Najib , Born William H. Vanden
Published: May 2019

Seeds of false cleavers (Galium spurium L.) grown in mid-May germinated 12 to 14 days after planting in central Alberta. The plants flowered from early July to late August and developed fruits from mid-July to early September. Plants from the late-June sowing date developed fruits until early October unless early fall frost killed the plants. Plants from seeds sown after mid-July remained in a vegetative state until late September and did not flower. Seedlings that emerged in August and September survived a mild prairie winter and resumed growth the following spring. Under greenhouse conditions, plant height ranged from 77 to 113 cm and the number of branches at first node ranged from 6 to 14, as plant density decreased from 16 to 1 plant/pot. Shoot dry weight decreased by 50% as plant population doubled, 46 days after emergence. The number of seeds produced/plant decreased from 3500 to 175 as plant density increased from 1 to 16 plants/pot. In growth chamber studies, plant growth was greatest at 20 compared to 16 or 24C.
Influence of Environmental Factors on Smallflower Morningglory (Jacquemontia tamnifolia) Germination and Growth
Authors: Shaw David R. , Smith H. Randy , Cole A. Wayne , Snipes Charles E.
Published: May 2019

The optimum pH for germination of smallflower morningglory (Jacquemontia tamnifolia(L.) Griseb. # IAQTA] seed was 8.0. A scarification time of 25 to 60 s using a drum scarifier with medium grit provided the best germination, and the optimum temperature for germination was 35 to 40C. However, the optimum temperature for growth was 25 to 35C, with reductions in growth occurring above or below this range. Emergence after 14 days was 81 and 49% at planting depths of 1.5 and 10 cm, respectively. Shade levels of 30 to 92% reduced smallflower morningglory growth by 38 to 87% compared to plants grown in full sunlight.
Efficacy of Postharvest Herbicides on Russian Thistle (Salsola iberica) Control and Seed Germination
Authors: Young Frank L. , Whitesides Ralph E.
Published: May 2019

Field and laboratory studies were conducted to evaluate the efficacy of several herbicides applied after small-grain harvest on Russian thistle (Salsola ibericaSennen and Pau # SASKR) control and subsequent seed germination. Best postharvest control of Russian thistle was with chlorsulfuron {2-chloro-N-[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino] carbonyl] benzenesulfonamide} treatments, paraquat (1,1′-dimethyl-4,4′-bipyridinium ion), and bromoxynil (3,5-dibromo-4-hydroxybenzonitrile) plus metribuzin [4-amino-6-(1,1-dimethylethyl)-3-(methylthio)-1,2,4-triazin-5(4H)-one], where control ranged from 73 to 96%. During the summer-fallow year, chlorsulfuron and paraquat decreased Russian thistle population and biomass compared to the untreated control. Germination of large seeds from plants treated with paraquat and both rates of chlorsulfuron was reduced at least 64% compared to seeds of similar size from untreated plants.
Imazaquin Persistence and Mobility in Three Arkansas Soils
Authors: Basham Gary , Lavy Terry L. , Oliver Lawrence R. , Scott H. Don
Published: May 2019

Field persistence of imazaquin {2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-3-quinolinecarboxylic acid} applied preemergence as high as 16 times the 0.14 kg ai/ha recommended rate was studied at two locations in Arkansas in 1984 and 1985. Rapid dissipation of these high rates occurred on the Taloka silt loam under hot, dry field conditions in 1984 when no rainfall occurred for 2 weeks after application. In 1985, when furrow irrigation was applied 7 days after application, imazaquin phytotoxicity was greater and dissipation was delayed. Imazaquin persistence and soil adsorption were greater on Sharkey silty clay than on Taloka silt loam. Following 3- and 8-cm irrigation, 84 and 78%, respectively, of the14C-labeled imazaquin remained in the surface 5 cm, but in plots covered between rainfalls and receiving 8 cm rain, 74% leached out of this top layer. Since nonincorporated imazaquin dissipated rapidly under hot, dry field conditions, carryover into the next growing season or leaching below the plow layer would not be expected. However, in cool, wet conditions immediately after application, the weakly adsorbed imazaquin molecule was readily bioavailable and mobile in the soil profile.
Physiological Responses to Sethoxydim in Tissues of Corn (Zea mays) and Pea (Pisum sativum)
Authors: Hosaka Hideo , Takagi Masae (Kubota)
Published: May 2019

The physiological responses of corn (Zea maysL. ‘Goldencrossbantam′) and pea (Pisum sativumL. ‘Alaska′) to sethoxydim {2-[1-(ethoxyimino)butyl]-5-[2-(ethylthio) propyl]-3-hydroxy-2-cyclohexen-1-one} were investigated. Sethoxydim did not affect excised pea root growth at 1 × 10−4M but inhibited excised corn root growth at concentrations of 1 × 10−8M and above. Treating corn impeded root growth with 1 × 10−7M sethoxydim within 4 h after treatment; however, little histological change of the roots was observed at 48 h. At 1 × 10−6M, growth nearly stopped within 4 h after treatment, and clear cytological changes of the roots were observed at 24 and 48 h. Sethoxydim inhibited both mitosis and DNA synthesis of excised corn root tips between 4 and 48 h after treatment. Respiration of corn roots measured by oxygen uptake and the TTC (2,3,5-triphenyltetrazolium chloride) test was not affected by the herbicide directly. Sethoxydim (1 × 10−4M) inhibited IAA-induced cell elongation of corn coleoptile and pea epicotyl by 37 and 12%, respectively. Sethoxydim selectively inhibited the growth of excised root tips of susceptible corn by affecting cell division rather than cell enlargement, and the inhibition mechanism of cell division (inhibition of mitosis) by the herbicide was not by direct inhibition of DNA synthesis or by effects on respiration.
Selectivity Mechanisms of Sethoxydim Absorption into Tissues of Corn (Zea mays) and Pea (Pisum sativum)
Authors: Hosaka Hideo , Takagi Masae (Kubota)
Published: May 2019

The selectivity mechanisms of sethoxydim {2-[1-(ethoxyimino)butyl]-5-[2-(ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-one} were investigated by examining absorption of14C-sethoxydim into tissues of corn (Zea maysL. ‘Goldencrossbantam′) and pea (Pisum sativumL. ‘Alaska′). Greater absorption of14C-sethoxydim was observed only into the proliferative 2-mm terminals of the excised roots of susceptible corn, and the same result was obtained with corn seedlings in hydroponic culture. Absorption was not affected by 1 × 10−4M 2,4-dinitrophenol (DNP), which indicated that the absorption of14C-sethoxydim is probably mediated by a passive transport system rather than an active transport system. The selective herbicidal action of sethoxydim appeared to depend largely on the differential rates of absorption into meristematic regions by the susceptible and tolerant plants.
Effect of Chlorsulfuron on the Movement and Fate of Diclofop in Italian Ryegrass (Lolium multiflorum) and Wheat (Triticum aestivum)
Authors: Liebl Rex , Worsham A. Douglas
Published: May 2019

The basis for chlorsulfuron {2-chloro-N-[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino] caronyl] benzenesulfonamide} antagonism of diclofop {(±)-2-[4-(2,4-dichlorophenoxy)phenoxy] propanoic acid} was investigated in Italian ryegrass [Lolium multiflorum(Lam.) # LOLMU] and wheat (Triticum aestivumL. ‘McNair 1813′). Chlorsulfuron did not affect the chemical stability or volatility of diclofop in spray mixtures over the time and concentration ranges evaluated. Addition of chlorsulfuron (0.11 μg/μl) to a diclofop (2.0 μg/μl) foliar-applied spotting solution did not affect the absorption, translocation, or metabolism of diclofop in 17-day-old Italian ryegrass or wheat. Italian ryegrass and wheat responded differentially to diclofop alone. At 72 h after treatment, 69 and 40% of labeled diclofop penetrated into Italian ryegrass and wheat leaves, respectively. Although little movement of labeled diclofop occurred in either species, more translocated from the treated zone of Italian ryegrass. At 72 h after treatment, the percentages of14C recovered as parent methyl ester, diclofop (free acid), and conjugates in treated leaf extracts were 9, 62, and 25%, respectively, for Italian ryegrass, and 50, 20, and 29%, respectively, for wheat. Differential penetration and metabolism of diclofop are the probable bases for selectivity between wheat and Italian ryegrass. The antagonism of diclofop caused by chlorsulfuron does not appear to be due to an alteration of the molecular fate of diclofop in Italian ryegrass.
Soybean (Glycine max) – Velvetleaf (Abutilon theophrasti) Interspecific Competition
Authors: Munger Philip H. , Chandler James M. , Cothren J. Tom , Hons Frank M.
Published: May 2019

In a 2-yr field study conducted on a Weswood silt loam soil (Fluventic Ustochrepts), interspecific competition between soybeans [Glycine max(L.) Merr. ‘Hutton′] and velvetleaf (Abutilon theophrastiMedik. # ABUTH) resulted in greater than 40 and 50% reductions in soybean and velvetleaf seed yield, respectively. Leaf area index, number of mainstem nodes, total number of leaves, and plant dry weight of monocultured and intercropped velvetleaf differed significantly as early as 4 weeks after emergence. Interspecific competition had litttle or no effect on soybean morphology before 8 weeks after emergence. Soil water extraction occurred to 1-m depths in a monoculture of velvetleaf (five plants/m2) in 1984 and 1985. Monocultured soybeans (32.5 plants/m2) extracted water from a 1.5-m or greater depth of the soil profile during the same years. Soil water extraction in the intercropped plots resembled that of the monocultured velvetleaf treatment until soybeans attained R6, when soil water was extracted to a 1.5-m depth. The potential for interspecific competition for water existed early in the season before late-season soybean root development. Relative water content and leaf water potential (Ψw1) did not differ (0.05) between monocultured and intercropped soybeans in 1984 or 1985. In 1985, Ψw1differed between monocultured and intercropped velvetleaf during anthesis. Leaf water potential values in the youngest, fully expanded leaves were approximately 0.3 and 0.4 MPa lower during midmorning and midday hours, respectively, in intercropped and monocultured velvetleaf. Transpiration and stomatal conductance did not differ between monocultured and intercropped soybeans or velvetleaf at any time during 1984. Photosynthetic and transpiration rates, stomatal conductance, and Ψw1were lower in intercropped than in monocultured velvetleaf during anthesis in 1985, suggesting interspecific competition for soil water. Soybean water relations were not affected in either year. The data suggest that soybean yield reductions in soybean-velvetleaf interspecific competition are attributable to resource limitations other than water in south-central Texas.
Lentil (Lens culinaris) Yield as Influenced by Duration of Wild Oat (Avena fatua) Interference
Authors: Curran William S. , Morrow Larry A. , Whitesides Ralph E.
Published: May 2019

Studies were conducted to evaluate the effect of wild oat (Avena fatua L. # AVEFA) interference in lentils (Lens culinaris Medik). An infestation of 32 and 65 wild oats/m2 maintained up to 5 weeks in the field did not reduce lentil grain yield. However, 32 wild oats/m2 reduced yields 32% when allowed to remain for 7 weeks and 49% if they remained until harvest time (11 weeks). Sixty-five wild oats/m2 reduced grain yield 42 and 61% for the same time periods, respectively. In the growth chamber, 69 wild oats/m2 reduced lentil plant dry weight 29% if allowed to remain for 3 weeks, 61% for 5 weeks, and 72% for 7 weeks (harvest time). The field data suggest that wild oat control measures may be delayed for several weeks after lentil emergence without reducing crop yield.
Annual Canarygrass (Phalaris canariensis) Tolerance and Weed Control Following Herbicide Application
Authors: Holt Neal W. , Hunter Jim H.
Published: May 2019

Field studies were conducted in Saskatchewan to evaluate the effect of herbicides on annual canarygrass (Phalaris canariensisL.) and associated weeds. Bromoxynil (3,5-dibromo-4-hydroxybenzonitrile) at 0.35 kg ai/ha, tank mixes of bromoxynil at 0.28 kg/ha plus the ester of MCPA [(4-chloro-2-methylphenoxy)acetic acid] at 0.28 kg ae/ha, linuron [N′-(3,4-dichlorophenyl)-N-methoxy-N-methylurea] at 0.28 kg ai/ha plus MCPA amine at 0.56 kg/ha, or propanil [N-(3,4-dichlorophenyI)propanamide] at 1.0 kg ai/ha plus MCPA ester at 0.28 kg/ha resulted in annual canarygrass seed and dry matter yields equal to the unsprayed check and excellent wild mustard (Sinapis arvensisL. # SINAR) and cow cockle (Vaccaria pyramidataMedik. # VAAPY) control. Metribuzin [4-amino-6-(1,1-dimethylethyl)-3-(methylthio)-1,2,4-triazin-5(4H)-one] at 0.21 kg ai/ha plus MCPA amine at 0.56 kg/ha reduced the crop stand in 1 out of 5 yr and seed yield every year. Postemergence application of difenzoquat (1,2-dimethyl-3,5-dipheny1-1H-pyrazolium) at 0.84 kg ai/ha or flamprop [N-benzoyl-N-(3-chloro-4-fluorophenyl)-DL-alanine] at 0.53 kg ai/ha, or preplant-incorporated triallate [S-(2,3,3-trichloro-2-propenyl)bis(1-methylethyl)carbamothioate] at 1.40 kg ai/ha optimized wild oat (Avena fatuaL. # AVEFA) control with seed yields. Diclofop {(±)-2-[4-(2,4-dichlorophenoxy)phenoxy)propanoic acid} at 0.70 kg ai/ha severely damaged annual canarygrass in all years. Triallate applied at 1.40 kg/ha preplant or preemergence incorporated marginally reduced the crop stand and seed yield compared to the untreated controls in tolerance tests.
Weed Control in a Conservation Tillage Rotation in the Texas Blacklands
Authors: Brown Steven M. , Chandler James M. , Morrison John E.
Published: May 2019

A field experiment was conducted to evaluate weed control systems in a conservation tillage rotation of grain sorghum [Sorghum bicolor(L.) Moench.] – cotton (Gossypium hirsutumL.) – wheat (Triticum aestivumL.). Herbicide systems included fall and spring/summer inputs of high and low intensity. Tillage regimes were no-till (NT) and reduced-till (RT) systems; the latter included fall primary tillage followed by spring stale seedbed planting. Both tillage systems utilized controlled traffic lanes and wide, raised beds. Effective johnsongrass [Sorghum halepense(L.) Pers. # SORHA] control required intense herbicide inputs at one or both application periods, i.e., in the fall and/or spring/summer. Grain sorghum and cotton yields for the most intense weed control system, which included high inputs in both the fall and spring/summer, were not superior to systems that included high inputs in only one of the two application periods. Seedling johnsongrass emergence occurred before spring planting in RT (but not in NT) in 2 of 3 yr, and control measures were ineffective. After 3 yr, the predominant weeds were johnsongrass and browntop panicum (Panicum fasciculatumSw. # PANFA).
Absorption and Translocation of14C-Chlorsulfuron and14C-Metsulfuron in Wild Garlic (Allium vineale)
Authors: Leys Andrew R. , Slife Fred W.
Published: May 2019

The absorption and translocation patterns of foliar applied14C- chlorsulfuron {2-chloro-N- [[(4-methoxy-6-methyl-1,3,5- triazin- 2 - yl)amino] carbonyl] benzenesulfon-amide} and14C-metsulfuron {2- [[[[(4-methoxy-6-methyl-1,3,5- triazin- 2-yl)amino] carbonyl] amino] sulfonyl] benzoic acid} in wild garlic (Allium vinealeL. # ALLVI) were similar. Both14C-chlorsulfuron and l4C-metsulfuron were readily absorbed by wild garlic, with 62 and 58%, respectively, of the applied doses absorbed 144 h after application. After 144 h, 17% of the applied14C-chlorsulfuron and 16% of the applied14C-metsulfuron were translocated out of the treated leaf, with the greatest amounts concentrating in young shoot tissues. Chlorsulfuron and metsulfuron reduced wild garlic shoot dry weight, height, and the number of leaves, more when they were applied to the foliage, or to both the foliage and the soil, than when they were applied to the soil alone.
Johnsongrass (Sorghum halepense) Control by Herbicides in Oil Diluents
Authors: Barrentine William L. , McWhorter Chester G.
Published: May 2019

Control of seedling and rhizome johnsongrass [Sorghum halepense(L.) Pers. # SORHA] with five herbicides was evaluated after postemergence application in various diluents and spray volumes using one to three types of applicators from 1983 to 1985. The rate of each herbicide required to control seedling johnsongrass using paraffinic oil as the diluent in applications with an external- or internal-mixing air-assist sprayer at a spray volume of 9.4 L/ha was one-half the rate required when water plus 1.25% (v/v) paraffinic oil concentrate (POC) or water plus 1.25% (v/v) soybean oil concentrate (SOC) were the diluents in applications with a conventional sprayer equipped with fan jet spray nozzles at a spray volume of 187 L/ha. Rates were also reduced when once-refined soybean oil was the diluent at a spray volume of 9.4 L/ha, except for the ethyl ester of quizalofop {(±)-2-[4-[(6-chloro-2-quinoxalinyl)oxy] phenoxy] propanoic acid}. Sethoxydim {2-[1-(ethoxyimino)butyl]-5-[2-(ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-one} was equally effective on seedling johnsongrass growing in soybeans [Glycine max(L.) Merr. ‘DPL 105’] when applied at 224 g ai/ha with an internal-mixing air-assist sprayer or a controlled-droplet applicator (CDA) at a spray volume of 9.4 L/ha and a conventional sprayer at a spray volume of 187 L/ha, regardless of diluent. Conventional application required the use of 1.25% (v/v) SOC or POC as part of the diluent to be effective. For three of the five herbicides evaluated on rhizome johnsongrass, paraffinic oil at a spray volume of 9.4 L/ha was the only diluent that resulted in season-long control. Rhizome johnsongrass control with this diluent also resulted in significantly higher soybean yields than all other diluent-spray volume treatments.
Volunteer Corn (Zea mays) Interference in Soybeans (Glycine max)
Authors: Beckett Thomas H. , Stoller Edward W.
Published: May 2019

Volunteer corn (Zea maysL. # ZEAMX) is a troublesome weed in soybeans [Glycine max(L.) Merr.] grown in the Corn Belt. Field studies were conducted in 1983 and 1984 at Champaign, IL, to determine the soybean growth and yield parameters affected by volunteer corn interference. Soybean yield was inversely and linearly related to volunteer corn clump density, with yield losses reaching 25% at 5380 clumps/ha (10 plants/clump). Volunteer corn clumps of 1, 4, 7, and 10 plants reduced soybean yields by 6, 16, 21, and 22%, respectively, at a density of 5380 clumps/ha. Treatments of either the butyl ester of fluazifop {(±)-2-[4-[[5-(trifluoromethyl)-2-pyridinyl]oxy]phenoxy] propanoic acid} or glyphosate [N-(phosphonomethyl)glycine] were applied at various dates between 2 and 12 weeks after soybean emergence (WAE) to a volunteer corn infestation of 5380 clumps/ha (10 plants/clump). Volunteer corn caused soybean yield losses of 2, 6, 12, 19, and 27% when herbicides were applied at 2, 4, 6, 8, and 10 WAE, respectively. Volunteer corn interference reduced soybean seed yield, plant dry weight, pod number, seed number, leaf fresh weight, and leaf area index, within 40 cm of a clump of 10 volunteer corn plants. A clump of 10 volunteer corn plants reduced soybean pod number/plant within a radius of 86 cm.
Factors Influencing Fluorochloridone Activity in No-Till Corn (Zea mays)
Authors: Buhler Douglas D.
Published: May 2019

Application time did not greatly influence control of velvetleaf (Abutilon theophrastiMedik. # ABUTH) or common lambsquarters (Chenopodium albumL. # CHEAL) in no-till corn (Zea maysL. ‘Pioneer 3747’) with fluorochloridone {3-chloro-4-(chloromethyl)-1-[3-(trifluoromethyl) phenyl]-2-pyrrolidinone}. Giant foxtail (Setaria faberiHerrm. # SETFA) control was reduced as much as 25% by 90 days after planting when fluorochloridone was applied early preplant rather than preemergence. Fluorochloridone at 0.8 kg/ha applied preplant or preemergence gave 83% or greater control of common lambsquarters and giant foxtail for the entire growing season. However, velvetleaf control with the same treatments was 61% or less. Fluorochloridone caused minimal corn injury. Greenhouse bioassay indicated that fluorochloridone may carry over and injure soybean[Glycine max(L.) Merr.] the year after application. Imbibition of fluorochloridone by seed of corn and giant foxtail did not reduce germination at concentrations up to 10-3M. Giant foxtail seedling fresh weight was reduced 80% following imbibition of 10-5M fluorochloridone. Corn seedling fresh weight was not reduced by imbibition of up to 10-4M fluorochloridone.
Response of Hard Red Spring Wheat to CGA-82725
Authors: Mohan Richard , Hassanein Elhassanein Elslirbini , Lym Rodney G. , Miller Stephen D.
Published: May 2019

The response of ‘Era’ (tolerant) and ‘Coteau’ (susceptible) hard red spring wheat (Triticum aestivumL.) to CGA-82725 2-propynyl ester of {2-[4- [(3,5-dichloro-2-pyridinyl)oxy] phenoxy] propanoic acid} was determined in field and greenhouse evaluations. Era wheat was most susceptible to CGA-82725 applied at early jointing through the boot stage. Coteau wheat was most susceptible at die two-leaf stage and between early jointing through spike emergence. Coteau was injured more than Era wheat as the CGA-82725 rate was increased from 0.14 to 0.28 kg ai/ha. Wheat grain yield reductions were greatest when CGA-82725 was applied at the early jointing through boot stage for both cultivars and averaged 73% of the control. Absorption and translocation of14C-CGA-82725 were similar and increased over time regardless of cultivar. Most of the absorbed14C remained in the treated leaf in both cultivars.
Effects of Phenolic Acids and Ragweed Parthenium (Parthenium hysterophorus) Extracts on Tomato (Lycopersicon esculentum) Growth and Nutrient and Chlorophyll Content
Authors: Mersie Wondimagegnehu , Singh Megh
Published: May 2019

The effects of caffeic, vanillic,p-coumaric, chlorogenic, and ferulic acids, ragweed parthenium (Parthenium hysterophorusL. # PTNHY) residue and extracts on the growth, ion uptake, and chlorophyll content of 3-week-old tomatoes (Lycopersicon esculentumMill. ‘Walter’) grown in the greenhouse were determined Vanillic,p-coumaric, chlorogenic, and ferulic acid at 10−3M and parthenium extract at 0.5% (w/v) significantly reduced tomato root and shoot dry weight. Ragweed parthenium residue at 0.5% (w/w) and extract at 0.5% (w/v) significantly reduced tomato shoot and root dry weight. Leaf nitrogen content was reduced by phenolic acids (10−3M) and ragweed parthenium extract (0.5%). Phosphorus content was reduced by all phenolic acids at 10−3M and ragweed parthenium extract at 0.5% (w/v). In addition,p-coumaric and ferulic acids at 10−4M reduced phosphorus content. No consistent relationship between chlorophyll content and tomato growth reduction was observed.
Absorption and Translocation of CGA-82725 by Additives
Authors: Gillespie Greg R. , Skrzypczak Grzegor A. , Nalewaja John D.
Published: May 2019

The influence of various additives on CGA-82725 [2-propanyl-2,4-(3,5-dichloro-2-pyridyloxy)phenoxy propanoate] absorption and translocation was determined in oats (Avena sativa L. ‘Lyon’). The absorption and translocation of 14C was greater when 14C-CGA-82725 was applied with petroleum oil compared to soybean [Glycine max (L.) Merr.] oil. The translocation of 14C was greater at 96 than 48 h after 14C-CGA-82725 application. The absorption of 14C was greater at 48 than 24 h but was similar at 48 and 96 h after 14C-CGA-82725 application with no additive, petroleum oil, or soybean oil. The absorbed and translocated 14C was greater when 14C-CGA-82725 was applied with oil at 1.2 compared to 0.6 L/ha. No additional increase in 14C absorption and translocation was obtained if the oil volume was increased to 2.3 L/ha. The addition of petroleum oil to 14C-CGA-82725 increased 14C absorption and translocation more than the addition of palm (Eleais quineeneis Jalq.), safflower (Carthamus tinctorius L.), linseed (Linum usitatissimum L.), or soybean oil. The four seed oils and the emulsifier At Plus 300F caused similar increases in 14C absorption and translocation over 14C-CGA-82725 applied alone. Ethylene glycol did not increase 14C absorption and translocation compared to 14C-CGA-82725 applied alone.
Basis for Differential Susceptibility of Rice (Oryza sativa), Wild Rice (Zizania palustris), and Giant Burreed (Sparganium eurycarpum) to Bentazon
Authors: Clay Sharon A. , Oelke Ervin A.
Published: May 2019

The basis for differential susceptibility of tolerant rice (Oryza sativaL.), susceptible wild rice (Zizania palustrisL.), and susceptible giant burreed (Sparganium eurycarpumEngelm. # SPGEU) to foliar application of 1.1 kg ai/ha of bentazon [3-(1-methylethyl)-(1H)-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide] was investigated by evaluating herbicide absorption, translocation, and metabolism. Giant burreed and wild rice absorbed more bentazon than rice at similar growth stages. Less than 10% of the absorbed bentazon was translocated out of the treated leaf of any of the species. Differential tolerance of bentazon among the three species was due to differences in the rate of bentazon metabolism. Rice metabolized 98% of the bentazon retained in the treated leaf 1 day after treatment (DAT), while giant burreed and wild rice metabolized less than 2% of the bentazon retained in the treated leaf 5 DAT.
Anthracnose of Florida Beggarweed (Desmodium tortuosum) Caused byColletotrichum truncatum
Authors: Gardina John , Littrell Robert H. , Hanlin Richard T.
Published: May 2019

Greenhouse and growth chamber studies were conducted to determine conditions for infection of the fungal pathogenColletotrichum truncatum(Schw.) Andrus and Moore on Florida beggarweed (Desmodium tortuosum(Sw.) DC. # DEDTO and to determine the host specificity of this fungus. Optimum conditions for disease development were 14 to 16 h incubation in 100% relative humidity (RH) at 24 to 29 C. Control of Florida beggarweed with 105to 107C. truncatumspores/ml was greatest in the cotyledon stage and decreased with plant age. Ten of 18Desmodiumspecies tested were susceptible to the Florida beggarweed isolate ofC. truncatumbut 13 other plant species and varieties were resistant and 61 were immune.
An Atomizer for Application of Very Low Volumes of Herbicide Solutions
Authors: Bucholtz Dennis L. , Hess F. Dan
Published: May 2019

The precise delivery of small quantities of herbicide solutions to leaf surfaces is difficult to achieve, yet most absorption research has this requirement. An atomizer for delivering microliter quantities of herbicide solutions has been designed, constructed, and tested. The function of the atomizer is to quantitatively apply low-volume (1-to 10-μl) solutions of herbicides, especially radioactive herbicides, to plant surfaces. The appearance of droplets from the atomizer and a flat-fan nozzle were similar and both yielded deposits that were much smaller than a 1-μl droplet applied by syringe. There was no splatter loss of herbicide when applied with the atomizer, and the bio-activity of the herbicide was equal to that applied as a single droplet. The atomizer yielded drops similar to those from a flat-fan nozzle and should produce absorption results more representative of those found under field conditions.
Bentazon Metabolism in Tolerant and Susceptible Soybean (Glycine max) Genotypes
Authors: Connelly James A. , Johnson Michael D. , Gronwald John W. , Wyse Donald L.
Published: May 2019

Previous reports have suggested that bentazon [3-(1-methylethyl)-(1H)-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide] tolerance among soybean genotypes is the result of differential translocation or metabolism. The basis for tolerance was reexamined using susceptible and tolerant genotypes. Tolerant genotypes (‘Hill’ and ‘Clark 63’) were found to tolerate 100- to 300-fold more bentazon than susceptible genotypes (‘L78–3263’, ‘Hurrelbrink’, and ‘PI 229.342’). Minor differences in absorption and translocation occurred among the genotypes but they did not correlate with tolerance. Tolerant genotypes metabolized 80 to 90% of absorbed bentazon within 24 h, while susceptible genotypes metabolized only 10 to 15%. Two major metabolites, the glycosyl conjugates of 6- and 8-hydroxybentazon, were formed in tolerant genotypes. Susceptible genotypes did not form the hydroxybentazon conjugates but instead produced relatively low levels of two unidentified metabolites. It is concluded that differential bentazon tolerance among soybean genotypes is linked to the ability to form both the 6- and 8-hydroxybentazon conjugates.
Metabolism as a Basis for Differential Atrazine Tolerance in Warm-Season Forage Grasses
Authors: Weimer Monte R. , Swisher Beth A. , Vogel Kenneth P.
Published: May 2019

Atrazine metabolism was studied in four warm-season forage grasses to determine if metabolism was the basis for differential atrazine tolerance among the grasses. Big bluestem and switchgrass are atrazine tolerant while indiangrass and sideoats grama are atrazine susceptible in the seedling stage. Metabolism of atrazine in big bluestem and switchgrass occurred primarily by glutathione conjugation. The major metabolic product isolated from indiangrass and sideoats grama was theN-deethylated metabolite of atrazine. Glutathione conjugation by big bluestem and switchgrass occurred at a faster rate thanN-dealkylation of atrazine in indiangrass and sideoats grama. Differential tolerance to atrazine among the grasses studied was probably due to the metabolic route by which they detoxify atrazine and the rate of metabolism for that specific route. Intraspecific differences in atrazine tolerance in indiangrass were due to the amount of metabolite produced in relationship to the amount of parent atrazine remaining in the shoot tissue. The more tolerant indiangrass lines had a higher metabolite to parent atrazine ratio than susceptible lines. This study confirmed differences in seedling atrazine tolerance of four indiangrass lines observed in previous greenhouse studies.
Translocation and Fate of Dicamba, Picloram, and Triclopyr in Horsenettle,Solanum carolinense
Authors: Gorrell Richard M. , Bingham Samuel W. , Foy Chester L.
Published: May 2019

Greenhouse studies were conducted to determine the extent of translocation from the foliage to fleshy roots, the inherent toxicity, and the fate of radiolabeled and nonlabeled dicamba, picloram, and triclopyr in horsenettle. Roots of horsenettle acted as the major sink for photosynthate accumulation at the 0.2- to 0.5-bloom growth stages as determined by autoradiography. Dicamba, picloram, and triclopyr were translocated into the roots of horsenettle and accumulation continued for at least 16 days.14C associated with each herbicide found in the roots ranged from 1.3% at 4 days to 3.8% at 16 days. After 16 days, slightly more14C from plants treated with dicamba and triclopyr (3.8 and 3.6%) than picloram (3.0%) was translocated to roots. These compounds were metabolized slowly in the foliage and roots as determined by thin-layer chromatography (TLC) and autoradiography. In translocation studies with horsenettle shoots, picloram at 1.12 kg/ha killed the treated and untreated shoots and roots. Dicamba and triclopyr at the highest rates killed the treated shoots and partially destroyed the root system. Symptoms were noted on the untreated shoots, but full recovery occurred at 8 weeks. Since each of the herbicides was metabolized slowly and only slight differences in their translocation were observed, the relatively higher herbicidal effectiveness of picloram must be attributed to its greater inherent potency.
Preemergence and Postemergence Activities of the (R) and (S) Enantiomers of Haloxyfop
Authors: Gerwick B. Clifford , Jackson Lucinda A. , Handly Jack , Gray Nick R. , Russell John W.
Published: May 2019

The relative activities of (R) and (S) enantiomers of the methyl ester of haloxyfop were determined on annual grasses. Samples enriched in the (S) enantiomer were markedly less active than the (R) in petri dish evaluations and foliar applications. The pure (S) enantiomer was estimated by regression to be 1000-fold or less active than the (R). The activity of the (S) enantiomer was found to be equivalent to that of the (R) following preemergence applications. Isolation and characterization of haloxyfop from soil treated with the methyl ester of haloxyfop indicated inversion of the (S) enantiomer to the (R) enantiomer within 7 days. Field trials confirmed the differential activity of enantiomers applied postemergence and their equivalence when applied preemergence. These findings indicate that inversion of the (S) enantiomer to the (R) occurs in soil following preemergence applications.
Competitive Relationships Among Winter Wheat (Triticum aestivum), Jointed Goatgrass (Aegilops cylindrica), and Downy Brome (Bromus tectorum)
Authors: Fleming Gwen F. , Young Frank L. , Ogg Alex G.
Published: May 2019

In three replacement series experiments, winter wheat (Triticum aestivumL.), jointed goatgrass (Aegilops cylindricaHost. #3AEGCY), and downy brome (Bromus tectorumL. # BROTE) were paired in all possible combinations to determine competitive relationships during vegetative growth. Under growth chamber conditions of ample fertility and soil moisture and day/night temperatures of 18/10 C, relative yield totals for the three species were similar, indicating that they compete for the same resources. Both winter wheat and jointed goatgrass had greater plant growth and higher relative crowding coefficients than downy brome, which indicated a hierarchy of relative competitiveness of winter wheat > jointed goatgrass >> downy brome. In other growth chamber studies, winter wheat was slightly more competitive than jointed goatgrass regardless of fertility levels. Winter wheat was the superior competitor at 18/10 C and −33 kPa (soil moisture), whereas jointed goatgrass was superior at 27/10 C and −300 kPa, conditions that are frequently encountered in the Pacific Northwest.
Photosynthesis and Growth Responses to Irradiance in Soybean (Glycine max) and Three Broadleaf Weeds
Authors: Regnier Emilie E. , Salvucci Michael E. , Stoller Edward W.
Published: May 2019

Photosynthesis and growth responses to irradiance level during growth were compared in soybean (Glycine maxL. Merr. ‘Century’) and three broadleaf weeds to determine if these responses were associated with differences in shade tolerance among species. In response to reduced irradiance during growth, leaf thickness of all species decreased, while chlorophyll content per unit leaf volume and photosynthetic rate per unit leaf volume, measured at low irradiance, increased. Soybean and common cocklebur (Xanthium strumariumL. #3XANST) also exhibited a decrease in soluble proteins on a leaf volume basis under reduced irradiance, and common cocklebur further exhibited a decrease in ribulose-1,5-bisphosphate carboxylase (RuBPcase) protein per unit leaf volume. Decreased irradiance during growth did not alter the content of RuBPcase or other soluble proteins per unit leaf volume in jimsonweed (Datura stramoniumL. # DATST) or velvetleaf (Abutilon theophrastiMedic. # ABUTH). The superior shade tolerance of common cocklebur compared to the other species was attributed in part to the levels of RuBPcase and other photosynthetic proteins in leaves developed at low irradiance.
Chlorsulfuron Adsorption by Humic Acid, Iron Oxides, and Montmorillonite
Authors: Borggaard Ole K. , Streibig Jens C.
Published: May 2019

An investigation of the adsorption of chlorsulfuron by four selected soil constituents, i.e. humic acid, two iron oxides, and montmorillonite, was carried out under concentration and pH conditions similar to those in most natural soils. CaCl2(0.01 M) was used as background electrolyte to suppress nonspecific adsorption. Negligible amounts of chlorsulfuron were adsorbed by montmorillonite, whereas humic acid and the iron oxides were found to be important adsorbents. For these adsorbents, chlorsulfuron adsorption decreased when pH increased from 4 to 8, with little adsorption occurring at pH 8. Adsorption by iron oxides was a function of their surface area. Chlorsulfuron adsorption was found to be closely related to the surface charge of the adsorbents, but in weakly acidic solution, also to the acid-base properties of chlorsulfuron itself.
Temperature Effects on Translocation Patterns of Several Herbicides within Quackgrass (Agropyron repens)
Authors: Harker K. Neil , Dekker Jack
Published: May 2019

A growth cabinet study was conducted to evaluate the effect of temperature on the distribution of several herbicides in quackgrass. Uniformly labeled14C-sucrose and the radiolabeled herbicides glyphosate, sethoxydim, cloproxydim, the butyl ester of fluazifop, the methyl ester of haloxyfop, and the ethyl ester of quizalofop were applied to quackgrass grown at three day / night temperature regimes (10/5, 20/15, and 30/25 C). Seven days after treatment the plants were harvested, lyophilized, and later sectioned, mapped, and oxidized in preparation for14C quantification. Quackgrass rhizome growth was more vigorous at 20/15 than 30/25 or 10/5 C. of the herbicides tested, haloxyfop was the most inhibitory to rhizome growth. Temperature increases from 10/5 to 20/15 or from 20/15 to 30/25 C resulted in more translocation to shoots. Increasing temperature had various effects on translocation to rhizomes depending on the chemical applied. At all three temperature regimes, more14C was recovered from distal than basal buds in plants treated with14C-sethoxydim. In contrast, at all three temperature regimes, similar amounts of14C were recovered from the distal and basal buds of plants treated with 14-C-sucrose.
Interference of Annual Weeds in Seedling Alfalfa (Medicago sativa)
Authors: Fischer Albert J. , Dawson Jean H. , Appleby Arnold P.
Published: May 2019

Barnyardgrass [Echinochloa crus-galli(L.) Beauv. #4ECHCG] and pigweeds (mixture ofAmaranthus retroflexusL. # AMARE andA. powelliiS. Wats. # AMAPO) seeded separately with alfalfa (Medicago sativaL.) in mid-August suppressed alfalfa severely before frost killed them in October and November. Some alfalfa was killed, and yield of alfalfa forage was reduced in each of three harvests the following year. These weeds did not harm alfalfa seeded in mid-September. Downy brome (Bromus tectorumL. # BROTE) and tumble mustard (Sisymbrium altissimumL. # SSYAL) suppressed alfalfa seeded in August and September. They reduced alfalfa stands and reduced yield of alfalfa forage in each of three harvests the following year. Alfalfa seeded August 27 and allowed to compete with a mixture of these species for various periods was injured most by weeds that emerged with the alfalfa and remained uncontrolled until forage harvest in May. These weeds did not reduce alfalfa yields if removed by 36 days after alfalfa emergence. Thereafter, yield decreased as the period of weed interference increased. Interference was most damaging in early spring, when growth of winter annual weeds was rapid and vigorous. Weeds seeded 65 or more days after alfalfa emergence did not reduce alfalfa yields but sometimes produced enough biomass to reduce the quality of the first-cutting alfalfa hay.
Influence of Cultivar Height on Competitiveness of Cotton (Gossypium hirsutum) with Johnsongrass (Sorghum halepense)
Authors: Bridges David C. , Chandler J. Mike
Published: May 2019

Research was conducted from 1983 through 1986 to compare the competitiveness of three cotton cultivars of different height with johnsongrass. Cultivars evaluated were: ‘1209-619-7’, ‘TAMCOT SP37-H’, and 'Stoneville 213’, which had an average height at maturity of 66, 122, and 168 cm, respectively. Each cultivar was grown with johnsongrass densities of 0, 4, and 6 plants/6 m of row with a 1-m row spacing. Johnsongrass biomass data confirmed that all three cultivars did compete with johnsongrass, but regression analyses using cultivar as a covariate revealed no difference in the competitiveness of the three cultivars.
Influence of Tillage Systems on Giant Foxtail,Setaria faberi, and Velvetleaf,Abutilon theophrasti, Density and Control in Corn,Zea mays
Authors: Buhler Douglas D. , Daniel Tommy C.
Published: May 2019

Giant foxtail density in corn was greater under no-till and chisel plow tillage systems than conventional or till plant. Giant foxtail density in no-till was 1400 shoots/m256 days after corn planting compared to 170 under conventional tillage. Velvedeaf density was greater under conventional tillage than all other tillage systems. Velvetleaf density was 120 plants/m256 days after corn planting under conventional tillage compared to 20 in no-till. Control of giant foxtail was often less under no-till or chisel plow conditions than conventional or till plant with the same herbicide treatment. Giant foxtail control with metolachlor treatments was affected less by tillage than similar treatments containing alachlor. Velvedeaf control was less with conventional tillage than other tillage systems when less than 1.7 kg/ha of atrazine was applied. Corn injury was not influenced by tillage systems. Corn yield was not affected by tillage systems under weed-free conditions. Several herbicide treatments resulted in corn yield similar to the weed-free under conventional tillage, but no herbicide treatment produced corn yield similar to the weed-free control under no-till conditions.
Growth and Water Relations of Douglas Fir (Pseudotsuga menziesii) Seedlings under Different Weed Control Regimes
Authors: Newton Michael , Preest David S.
Published: May 2019

Growth of Douglas fir [Pseudotsuga menziesii (Mirb.) Franco] was increased by controlling grasses and broadleaf herbs with eight herbicide regimes during the first 3 yr after planting on a well-drained moist site in the Oregon Coast Range. The greatest growth occurred if weeds were controlled in the same growing season that tree seedlings were transplanted to the field; smaller increments came from second- and third-year weed control. Growth increases attributable to early weed control continued through the fifth year, indicating that conditions during establishment strongly influenced later growth. Plots with no herbaceous vegetation had more available soil water than those with competing vegetation, and tree seedlings on these plots experienced less water stress. Irrigation in the third year increased stem diameter of seedlings in that year but had no effect thereafter. Increases in average seedling stem volume at 5 yr after transplanting were linearly related (r2 = 0.77) to the difference in observed xylem potential during the first three growing seasons after transplanting and the xylem potential at which photosynthesis ceased, −2 MPa.
Joint Effects of Acifluorfen Applications and Soybean Thrips (Sericothrips variabilis) Feeding on Soybean (Glycine max)
Authors: Huckaba Randy M. , Coble Harold D. , Van Duyn John W.
Published: May 2019

Field studies were conducted during 1983 and 1984 to determine the single and interactive effects of trifluralin, soybean thrips, and the sodium salt of acifluorfen on soybean. Increased soybean injury was observed in 1983 when acifluorfen at 0.6 kg ai/ha was applied to soybeans infested with soybean thrips versus plants where soybean thrips were controlled. Soybean injury measured by percent defoliation and visual injury ratings was reduced when thrips were controlled versus soybeans where thrips were not controlled with carbaryl at 0.9 kg ai/ha in 1983. Soybean thrips alone did not reduce soybean seed yield in this study. Acifluorfen reduced soybean photosynthetic rate, shoot weight, root weight, and seed yield. Trifluralin had no effect on soybean growth parameters measured in this study.
Plant Growth Response to the Phytotoxin Viridiol Produced by the FungusGliocladium virens
Authors: Jones Richard W. , Lanini W. Thomas , Hancock Joseph G.
Published: May 2019

Gliocladium virens, when grown on peat moss amended with sucrose and ammonium nitrate and then applied to soil, resulted in root necrosis. Herbicidal activity was correlated with fungal production of the phytotoxin viridiol. Viridiol had a wide spectrum of activity; it was particularly effective against annual composite species but was less effective in monocot control. Emergence of most weeds was reduced >90% at application rates of 8.7% (of total volume) or less. Treated seedling dry weights were drastically reduced. Applications of 4.5% reduced root and shoot weight of redroot pigweed by 93 and 98%, respectively. Crops were affected at higher treatment levels; however, the toxicity was readily avoided by applying the mycoherbicide out of the root zone of the crop, instead applying it between the seed and the soil surface. Viridiol production, which confers herbicidal activity, was detected 3 days after incorporation of the fungus-peat mixture. Viridiol production peaked on days 5 and 6 at approximately 25 μg viridiol/100 ml soil, based upon an application rate of 11%, then declined to undetectable levels by the end of 2 weeks.