bluuebunny/crossref_metadata_2025 huggingface dataset:
Biologically Effective Dose and Selectivity of RPA 201772 for Preemergence Weed Control in Corn (Zea mays)
Authors: Knezevic Stevan Z. , Sikkema Peter H. , Tardif Francois , Hamill Allan S. , Chandler Kevin , Swanton Clarence J.
Published: March 2018

Field studies were conducted in 1996 and 1997 at three locations throughout southern Ontario with the objective of developing dose-response curves of RPA 201772 for weed control and crop tolerance in corn. The biologically effective doses required to control redroot pigweed, velvetleaf, and wild mustard were 100, 90, and 80 g/ha, respectively. Yellow foxtail was controlled with 100 to 120 g/ha, while rates for common lambsquarters varied from 60 to 130 g/ha, depending on the year and location. Wild buckwheat control was poor (> 30%) at all of the doses tested. RPA 201772 did not reduce corn grain yield; however, temporary crop injury was evident on coarse sandy soils.
Cogongrass in the United States: History, Ecology, Impacts, and Management
Authors: Dozier Hallie , Gaffney James F. , McDonald Sandra K. , Johnson Eric R.R.L. , Shilling Donn G.
Published: March 2018

Cogongrass is a weed throughout the tropics and subtropics. Introductions early this century have spread into forests, rangelands, reclaimed mined areas, roadsides, and natural ecosystems in the southeastern United States. Vegetative reproduction is the primary mechanism for survival and local spread, and sexually produced seeds of this obligate outcrossing species provide natural long-distance dispersal. Highly germinable (≥ 90%) seeds have no dormancy, though spikelet fill may be low (≤ 40%) in natural populations. Early seedling establishment, prior to rhizome development, is low (< 20%), occurring in areas with little competition; ≥ 75% bahiagrass sod cover is required to prevent cogongrass seedling establishment. Imazapyr and glyphosate are the most effective herbicides for cogongrass control. Younger cogongrass shoots are very susceptible to these herbicides; however, longer term control of adult plants requires translocation and thereby control of the rhizomes. Autumn applications of glyphosate and imazapyr provided greatest suppression of rhizome regrowth. Effective cogongrass management options exist and depend on integrating several control strategies. Mechanical control alone provides short-term control, whereas multiple discings plus herbicide application provide longer term control. Some combinations of herbicide, discing, and revegetation with desirable plant species provide excellent control. Because of the large geographic area infested with cogongrass and the often economically and environmentally unacceptable management techniques, biological control organisms also should be researched.
Red Rice (Oryza sativa) Biology. II. Ecotype Sensitivity to Herbicides
Authors: Noldin Jose A. , Chandler James M. , Ketchersid Mary L. , McCauley Garry N.
Published: March 2018

Greenhouse studies were conducted to evaluate sensitivity of red rice ecotypes from Arkansas, Louisiana, Mississippi, and Texas to soil- and foliar-applied herbicides. Ecotype response to herbicides was variable. Molinate at 4.48 kg ai/ha controlled red rice ecotypes 92 to 100% and cultivars ‘Lemont,’ ‘Mars,’ and ‘Maybelle’ 39 to 63%. Red rice control with thiobencarb at 4.48 kg ai/ha was at least 89%. The tank mixture of fenoxaprop at 0.08 kg ai/ha plus fluazifop-P at 0.10 kg ai/ha controlled red rice and rice cultivars more than for either herbicide applied alone. Red rice and rice cultivar control with paraquat at 0.70 kg ai/ha was 83 to 100%. Blackhulled red rice TX 4 was less sensitive to paraquat and glufosinate than other ecotypes and cultivars. Glufosinate at 1.12 kg ai/ha was required to provide at least 94% control of ecotype TX 4.
Economic Comparison of Herbicides for Johnsongrass (Sorghum halepense) Control in Glyphosate-Tolerant Soybean (Glycine max)
Authors: Mckinley Tammy L. , Roberts Roland K. , Hayes Robert M. , English Burton C.
Published: March 2018

Returns to land, management, and risk were compared where glyphosate and four graminicides (quizalofop-P, fluazifop-P, sethoxydim, and clethodim) were used for johnsongrass control in glyphosate-tolerant soybean. In 1994 and 1995, returns to land, management, and risk for glyphosate-tolerant soybean were highest using glyphosate and lowest using sethoxydim. Break-even analysis showed that yields needed for equivalent returns with any nontransgenic soybean cultivar treated with any of the graminicides could range from 67 kg/ha less to 202 kg/ha more than the yields achieved with glyphosate. Based on this methodology, farmers would increase their return to land, management, and risk by planting glyphosate-tolerant soybean if expected yield from a standard cultivar treated with a standard herbicide program were less than the break-even yield.
Effect of Perennial Grasses on Canada Thistle (Cirsium arvense) Control
Authors: Wilson Robert G. , Kachman Stephen D.
Published: March 2018

An experiment was conducted near Scottsbluff, NE, to assess three techniques for establishing perennial grasses in pasture sites and to evaluate the effectiveness of five perennial grasses compared with herbicide or mowing for Canada thistle control. Perennial grass density 9 mo after seeding and perennial grass biomass 12 mo after seeding both followed the same trend, indicating that preplant rototilling improved perennial grass establishment. After 3 yr, Canada thistle control was greater than 90% in plots where perennial grasses had been established utilizing preplant rototilling, and competitive grasses were as effective as yearly applications of clopyralid at 0.55 kg/ha for controlling Canada thistle. Averaged across two studies conducted for 3 yr, hybrid wheatgrass, intermediate wheatgrass, Russian wildrye, tall fescue, and western wheatgrass provided 85, 74, 76, 78, and 66% Canada thistle control, respectively.
Volunteer Barley (Hordeum vulgare) Control in Winter Wheat (Triticum aestivum) with MON 37500
Authors: Shinn Sandra L. , Thill Donald C. , Price William J.
Published: March 2018

Spring barley often is grown in rotation with winter wheat, and sometimes barley can overwinter in the subsequent winter wheat crop reducing grain yield and quality. Studies were established during 1996 and 1997 in winter wheat fields in southeastern Washington and near Moscow, ID, respectively, to evaluate control of ‘Steptoe’ volunteer barley with MON 37500, diclofop, and fenoxaprop/2,4-D/MCPA. Herbicides were applied to volunteer barley at two growth stages: two leaves to four tillers and more than four tillers with stems beginning to elongate. MON 37500 at 0.018, 0.026, and 0.035 kg ai/ha visibly controlled volunteer barley 83% or more at both application times. Diclofop at 1.12 kg ai/ha did not control volunteer barley, whereas fenoxaprop/2,4-D/MCPA at 0.66 kg ai/ha controlled volunteer barley 64 to 97% in 1996, but only 0 to 23% in 1997. In 1996 and 1997, volunteer barley density was reduced 80 to 99% in MON 37500-treated plots compared to the untreated control plots. Wheat grain grade was #1 for all MON 37500 treatments compared to grade #4 in 1996 and #3 in 1997 in the untreated plots. Grain price was reduced by dockage (barley kernels) for MON 37500-treated wheat $0 to $3.12/metric ton (MT), whereas price was reduced $23 to $26/MT for grain from untreated plots. In greenhouse studies, visible injury and height and biomass reduction varied among the 36 barley varieties treated with MON 37500.
Inheritance of an ALS-Cross-Resistant Common Cocklebur (Xanthium strumarium) Biotype
Authors: Ohmes G. Anthony , Kendig J. Andy
Published: March 2018

A greenhouse experiment was conducted from 1995 to 1996 to determine the inheritance of ALS-cross-resistant common cocklebur. Two known biotypes (ALS-susceptible and ALS-resistant) were used in the experiment. Susceptible biotypes were crossed with pollen from resistant biotypes. F1 plants were self-pollinated. F2 plants were sprayed postemergence (POST) with a tank mixture of imazaquin at 280 g ai/ha and chlorimuron at 18 g ai/ha. Three distinct responses were observed: (1) no apparent effect (resistant), (2) yellowing of leaves with live terminals (intermediate), and (3) yellow leaves with dead terminals (typical symptoms of an ALS-susceptible common cocklebur). Chi-square tests indicated that an incomplete dominance model did not fit the data. Responses one and two were, therefore, combined and chi-square tests indicated a complete dominance model fit the data. This indicates that the cross-resistant trait is a dominant to semidominant trait.
Efficacy and Crop Response to Glufosinate-Based Weed Management in PAT-Transformed Sweet Corn (Zea mays)
Authors: Van Wychen Lee R. , Harvey R. Gordon , Vangessel Mark J. , Rabaey Thomas L. , Bach David J.
Published: March 2018

Field studies were conducted at Arlington, WI, in 1996 and 1997 and at Georgetown, DE, and LeSueur, MN, in 1997 to determine weed control efficacy, crop injury, and yield response of PAT-transformed sweet corn to glufosinate-based weed management. Sequential applications of glufosinate 10 to 18 d apart at 0.4 and 0.3 kg ai/ha controlled common lambsquarters, common ragweed, velvetleaf, wild-proso millet, and fall panicum 90% or better at all locations. Weed control varied little among 0.3, 0.4, or 0.3 and 0.3 (sequential) kg/ha glufosinate rates. Glufosinate applied alone, with, or following atrazine controlled velvetleaf 90% or greater but was less consistent on common ragweed and common lambsquarters (73 to 100%). Atrazine plus metolachlor applied preemergence (PRE) and glufosinate applied alone postemergence (POST) provided inconsistent wild-proso millet and fall panicum control (43 to 99%). Metolachlor followed by glufosinate improved consistency of grass control (> 76%). Glufosinate followed by cultivation provided 80% or greater control of velvetleaf and wild-proso millet. Glufosinate did not injure or delay maturity of PAT-transformed sweet corn. Sweet corn treated with glufosinate resulted in yields greater than or equal to the sweet corn that was hand-weeded or received a standard herbicide treatment.
Summer Fallow and After-Planting Bermudagrass (Cynodon dactylon) Control Programs for Sugarcane (Saccharumspp. hybrids)
Authors: Miller Donnie K. , Griffin James L. , Richard Edward P.
Published: March 2018

Based on bermudagrass ground cover 2 wk prior to sugarcane planting, tillage plus glyphosate applied postemergence sequentially at 3.4 followed by 2.2 kg ai/ha or a single application at 3.4 kg/ha during the summer fallow period was more effective than tillage alone. Effectiveness of tillage was enhanced when less rainfall was received during the summer fallow period the first year. Rainfall of less than 1 cm 20 d after preemergence application of sulfometuron at 0.2 kg ai/ha in June resulted in 100% bermudagrass ground cover the first year compared with 37% the second year with 15 cm of rainfall during the same period. Terbacil applied after sugarcane planting and metribuzin applied in February resulted in bermudagrass ground cover in May or June of 62% (experiment 1) and 2% (experiment 2) when sulfometuron was used during the fallow period, but no more than 5% when terbacil and metribuzin followed glyphosate plus tillage or tillage alone. In most cases, bermudagrass ground cover at that time was greater when the same glyphosate/tillage treatments were followed by atrazine after planting and pendimethalin plus atrazine in February compared with terbacil after planting and metribuzin in February. When after-planting and February herbicide treatments were applied, sugarcane stalk population, height, and yield each was equivalent regardless of the previous fallow treatment.
Plant Growth Regulators Alter the Growth of ‘Tifway’ Bermudagrass (Cynodon transvaalensis×C. dactylon) and Selected Turfgrass Weeds
Authors: Lowe David B. , Whitwell Ted
Published: March 2018

Growth-regulating characteristics of trinexapac-ethyl, paclobutrazol, and flurprimidol were investigated on ‘Tifway’ bermudagrass and four turfgrass weeds (large crabgrass, goosegrass, bahiagrass, and purple nutsedge). All treatments reduced the height of Tifway bermudagrass (25 to 37%) and large crabgrass (14 to 34%), but the height of purple nutsedge, goosegrass, and bahiagrass was not consistently changed. In 1995, all rates of trinexapac-ethyl reduced clipping weights of Tifway bermudagrass (70 to 87%) and bahiagrass (53 to 59%) more than large crabgrass, goosegrass, or purple nutsedge (< 39%). Trinexapac-ethyl (0.4 kg ai/ha) and paclobutrazol (1.1 kg ai/ha) applications increased both large crabgrass clipping weight and canopy visible density. Increased large crabgrass density was attributed to greater tiller numbers with trinexapac-ethyl (60 tillers/pot) and paclobutrazol (63 tillers/pot) compared to untreated large crabgrass plants (53 tillers/pot). Weed growth was not suppressed as much as Tifway bermudagrass growth; therefore, turfgrass stands may be adversely affected by plant growth regulator use under weedy conditions.
Control of Yellow and Purple Nutsedges (Cyperus esculentusandCyperus rotundus) in Turfgrass with MON-12051
Authors: Czarnota Mark A. , Bingham S. Wayne
Published: March 2018

Field studies were conducted from 1993 to 1995 to evaluate MON-12051 for turfgrass tolerance and control of yellow and purple nutsedges. The availability of herbicides for selective control of these weeds in turfgrass is limited. A sulfonylurea compound, MON-12051, has recently been developed for selective control of the nutsedges in turfgrass. When MON-12051 was applied at 0.07 to 0.14 kg ai/ha, the injury to Kentucky bluegrass, tall fescue, bermudagrass, and zoysiagrass was slight, with a maximum of 10% injury. At these rates, MON-12051 outperformed both bentazon and imazaquin in controlling yellow and purple nutsedges. Averaged over all tests 6 wk after treatment, yellow nutsedge control with MON-12051 was 83%. Control averaged 44% during the same period when treated with bentazon, whether applied once at 2.24 kg ai/ha or twice at 1.12 kg ai/ha. Purple nutsedge control averaged 96% when treated with MON-12051 in Kentucky bluegrass, while control was 42% with imazaquin applied at 0.19 and 0.43 kg ai/ha.
A Measurement of the Total Mass of Spray and Irrigation Mixtures Intercepted by Small Whole Plants
Authors: Wauchope R. D. , Sumner H. R. , Dowler C. C.
Published: March 2018

A plant-weighing procedure was used to measure the total mass of spray mixture intercepted by small whole corn and cotton plants. Mixtures of water and water plus crop oil concentrate or spreader–sticker were applied at spray volumes of 280 to 28,000 L/ha. The plants were weighed before and after passing under the spray and leaf areas, and shoot fresh and dry weights for each plant were measured. Spray deposition increased with spray volumes but not proportionally. Corn plants were larger than cotton plants and retained more spray per plant; however, cotton retained more spray per unit leaf area. The two adjuvants had similar effects on deposition, tending to increase it in corn and decrease it in cotton.
Tillage and Nitrogen Influence Weed Population Dynamics in Barley (Hordeum vulgare)
Authors: O'Donovan John T. , McAndrew David W. , Thomas A. Gordon
Published: March 2018

Field experiments were initiated at Alliance and Hairy Hill, Alberta, in 1989 to investigate the effects of conventional tillage, zero tillage, and four levels of nitrogen fertilizer on continuous barley production. In both tillage systems, the nitrogen was banded 6 to 8 cm deep between alternate barley rows. Herbicides were used for weed control each year. The influence of tillage and nitrogen on weed seed population dynamics was determined in 1991 and 1992. In the zero-tillage system, a large proportion of the weed seeds were present either at the soil surface or at the 5- to 10-cm depth. Green foxtail, the dominant species at Alliance, was also present at Hairy Hill where field pennycress was dominant. Green foxtail was consistently associated with low (residual) nitrogen and, in most cases, with conventional tillage. At both locations, green foxtail populations tended to decrease to very low levels as nitrogen rate increased, especially in zero tillage. At Hairy Hill, field pennycress populations in the soil seedbank were higher in zero tillage compared with conventional tillage, but plants that emerged from the soil seedbank in the field in spring were lower in zero tillage. Field pennycress populations were highest under low nitrogen. The results indicate that banding nitrogen has the potential to be an effective tool for green foxtail and field pennycress management in conventional- and zero-tillage systems, resulting in less dependence on herbicides for their control.
Rate and Time of Bentazon/Atrazine Application for Broadleaf Weed Control in Corn (Zea mays)
Authors: Hamill Allan S. , Zhang Jianhua
Published: March 2018

The effects of herbicide–adjuvant combinations and times of application on weed density and corn yield were determined in a 3-yr field study. At a given rate and time of application of bentazon/atrazine, Assist and Merge were equally effective adjuvants. Assist would be the adjuvant of choice for bentazon/atrazine rather than Merge because of its currently lower cost. Weed density depended on the rate and time of application of bentazon/atrazine. In general, bentazon/atrazine applied at early stages (7 d after emergence) of the development of corn seedlings or at high or intermediate rate (1.6 or 0.8 kg ai/ha) maintained low weed densities, with a relatively small range of variation over years. Delay in time (14 or 21 d after emergence) or reduction in herbicide rate (0.4 kg ai/ha) increased the risk of high weed pressure, although it was not always associated with yield loss. The best time for the application of postemergence herbicide appears to be a few days prior to the onset of the critical period of weed control.
Application Timing for Weed Control in Corn (Zea mays) with Dicamba Tank Mixtures
Authors: Spandl Eric , Rabaey Thomas L. , Kells James J. , Harvey R. Gordon
Published: March 2018

Optimal application timing for dicamba–acetamide tank mixes was examined in field studies conducted in Michigan and Wisconsin from 1993 to 1995. Dicamba was tank mixed with alachlor, metolachlor, or SAN 582H and applied at planting, 7 d after planting, and 14 d after planting. Additional dicamba plus alachlor tank mixes applied at all three timings were followed by nicosulfuron postemergence to determine the effects of noncontrolled grass weeds on corn yield. Delaying application of dicamba–acetamide tank mixes until 14 d after planting often resulted in lower and less consistent giant foxtail control compared with applications at planting or 7 d after planting. Corn grain yield was reduced at one site where giant foxtail control was lower when application was delayed until 14 d after planting. Common lambsquarters control was excellent with 7 or 14 d after planting applications. At one site, common lambsquarters control and corn yield was reduced by application at planting. Dicamba–alachlor tank mixes applied 7 d after planting provided similar weed control or corn yield, while at planting and 14 d after planting applications provided less consistent weed control or corn yield than a sequential alachlor plus dicamba treatment or an atrazine-based program.
Design, Construction, and Operation of Tilted Beds to Simulate Agricultural Runoff in Vegetative Filter Strips
Authors: Mersie Wondi , Seybold Cathy A.
Published: March 2018

This paper describes the design, construction, and operation of tilted beds to investigate the effectiveness of vegetative filter strips (VFS) in removing agricultural chemicals from runoff water. The beds are designed to catch surface runoff, leachate, and subsurface lateral flow. Switchgrass was established on beds filled with Cullen clay loam or Emporia sandy loam. Switchgrass establi shed on Cullen clay loam beds reduced surface runoff by 60% and by 11% in sandy loam containing switchgrass compared to respective bare soils. Infiltration was 64, 26, 17, and 8% for clay loam with switchgrass, clay loam without switchgrass, sandy loam with switchgrass, and sandy loam without switchgrass, respectively.
Potato (Solanum tuberosum) Tolerance and Susceptibility of Eight Weeds to Rimsulfuron with and without Metribuzin
Authors: Robinson Darren K. , Monks David W. , Monaco Thomas J.
Published: March 2018

Field studies were conducted to determine response of ‘Atlantic’ and ‘Fontenot’ potato varieties and eight weed species to rimsulfuron and metribuzin. Rimsulfuron was applied at 9, 18, 27, 35 and 70 g ai/ha and metribuzin at 69, 140, 210, 280 and 560 g ai/ha. Each herbicide was applied PRE or POST alone or in 1:8 combinations of rimsulfuron to metribuzin. Yield of either variety was not reduced by any treatment. Rimsulfuron applied PRE or POST at the suggested field use rate of 35 g/ha controlled smooth pigweed, redroot pigweed, ivyleaf morningglory, and common cocklebur 100%, common lambsquarters 90%, and jimsonweed 60%. Large crabgrass and fall panicum were controlled 92% by rimsulfuron at 35 g/ha. Reduced rates of 9 g/ha rimsulfuron plus 69 g/ha metribuzin, applied PRE or POST, controlled all weeds 100% except jimsonweed, fall panicum, and large crabgrass. For complete control of these weeds, rimsulfuron at 35 g/ha plus metribuzin at 280 g/ha was required.
Relationships Among Green Foxtail (Setaria viridis) Seedling Development, Growing Degree Days, and Time of Nicosulfuron Application
Authors: Forcella Frank , Banken Kevin R.
Published: March 2018

Success of postemergence weed management often depends upon application timing and weed seedling size. To develop a predictive tool for estimating green foxtail development and optimizing timing of management operations, seedling growth was monitored in fields for two years, as well as in a single greenhouse experiment, and compared with elapsed thermal time (growing degree days, GDD, base 10 C). The relationship between seedling height (mm) and GDD was similar both years and could be described by the following equation: Height = (-0.27 + 0.033 * GDD)2. A comparable equation described seedling growth in a greenhouse. Leaf number was linearly related to GDD. Green foxtail in corn was controlled with nicosulfuron applied at seven intervals between 100 and 450 GDD after corn planting in 1993 and 1994. In 1993 corn yield losses due to green foxtail interference were least when nicosulfuron was applied 200 to 300 GDD after planting, at which time green foxtail height was 50 to 100 mm. In 1994 corn yield losses were minimized if nicosulfuron was applied any time before 300 GDD.
Control of Mannagrass (Glyceria declinata) and Southern Watergrass (Luziola fluitans) in Water-seeded Rice (Oryza sativa)
Authors: Braverman Michael P.
Published: March 2018

Preplant control of mannagrass was greater than 90% with clethodim, glyphosate, sethoxydim, and sulfosate. Glyphosate at 0.5 to 1.0 kg ai/ha controlled mannagrass greater than 97%, and was not increased with any adjuvant. Fenoxaprop applied POST controlled mannagrass 97% but injured rice 33%. Except for fenoxaprop-ethyl, all POST treatments increased rice yields at least 1560 kg/ha more than the non-treated check. Southern watergrass was controlled 79 and 89% with 1.0 kg ai/ha glyphosate and 4.5 kg ai/ha sulfosate, respectively, while control was less than 55% with other herbicides.
Imidazolinone Herbicide Effects on Following Rotational Crops in Southern Alberta
Authors: Moyer James R. , Esau Rudy
Published: March 2018

The effect of imazethapyr and imazamethabenz on following crops was tested in southern Alberta, on Dark Brown and Brown Chernozemic soils, to assess the potential restrictions placed on cropping sequences by the use of these herbicides. Imazamethabenz reduced the yield of sugarbeet seeded one year after application. After imazethapyr application there is risk of yield loss with flax, corn, meadow bromegrass, mustard, sunflower, timothy, and wheat seeded one year later; canola seeded up to two years later; and sugarbeet and potato seeded up to three years later. Legume crops and intermediate wheatgrass may be seeded the year after application with little risk of yield loss. The required recropping intervals limit the use of imazethapyr for weed control in pea, alfalfa, or dry bean in cropping sequences that include sugarbeet, canola, or potato.
Water Use Efficiency as a Method for Predicting Water Use by Weeds
Authors: Norris Robert F.
Published: March 2018

Water use by weeds is one type of loss that contributes to the cost of weeds to agriculture. Water use efficiency provides a mechanism by which water use by weeds can be estimated. Uncontrolled weed growth could result in estimated irrigation costs exceeding $50.00/ha. Weeds like barnyardgrass at threshold densities in irrigated crops like sugarbeet or tomato are estimated to increase production costs by about $20.00/ha depending on water cost.
Experimental Parameters Used to Study Pesticide Degradation in Soil
Authors: Blumhorst Michael R.
Published: March 2018

Characterization of pesticide degradation in soil is an important component in determining the environmental impact of agriculturally-applied pesticides. Several techniques currently are being used to generate these data, but small-scale laboratory studies remain one of the most effective, cost-efficient mechanisms of evaluating pesticide behavior in soil. With small-scale studies, many different environmental factors can be incorporated into the experimental design, and with the use of14C-labeled material, these studies (often referred to as soil degradation or soil metabolism studies) provide information on test substance persistence, degradation, volatilization, and mineralization. Care must be exercised, however, in selecting the experimental parameters to be used because of the potential adverse or artificial effects on the soil system.
Microbiological Aspects of Environmental Fate Studies of Pesticides
Authors: Skipper Horace D. , Wollum Arthur G. , Turco Ronald F. , Wolf Duane C.
Published: March 2018

Surface and subsurface soils are complex biological, chemical, and physical environments and to understand the fate of pesticides in the soil environment is a formidable task. To determine the environmental fate of pesticides requires a diverse array of techniques and procedures. Microbiological approaches range from applied to basic, laboratory to field, qualitative to quantitative, and from low to high technology. In the arena of biodegradation, teams of scientists are needed to develop predictive models for the behavior of pesticides in the soil environment. From our perspectives, we have documented the existing status of the microbiology of environmental fate studies with pesticides. Verification of data from laboratory studies to the field environment is needed. On the other hand, efforts to design better field studies to assess microbial processes are essential to advance our understanding of environmental fate studies with pesticides.
Preemergence Weed Control in Conventional-Till Corn (Zea mays) with RPA 201772
Authors: Young Bryan G. , Hart Stephen E. , Simmons F. William
Published: March 2018

Field studies were conducted at Dekalb, Urbana, and Brownstown, IL, in 1996 and 1997 to evaluate corn (Zea mays) injury and weed control from preemergence applications of RPA 201772 alone and tank-mixed with metolachlor, atrazine, or both. No significant corn injury from RPA 201772 was observed at any time for all experiments. Giant foxtail (Setaria faberi) control at 60 days after treatment (DAT) was variable and ranged from 47 to 93% for RPA 201772 applied alone at 105 g ai/ ha. Giant foxtail control of at least 90% was observed by applying metolachlor at 1,120 g ai/ha with 105 g/ha RPA 201772. The addition of atrazine at either 1,120 or 1,680 g ai/ha improved control of giant foxtail compared with RPA 201772 applied alone at 105 g/ha in two of the six studies. RPA 201772 applied at 105 g/ha controlled at least 88% of velvetleaf (Abutilon theophrasti), Pennsylvania smartweed (Polygonum pensylvanicum), and smooth pigweed (Amaranthus hybridus). RPA 201772 controlled 88% or less of common waterhemp (Amaranthus rudis), common ragweed (Ambrosia artemisiifolia), and common cocklebur (Xanthium strumarium). Control of these three species was 92% or greater with RPA 201772 plus atrazine. Control of common lambsquarters (Chenopodium album) was at least 96% with RPA 201772 applied alone at any rate in four of the six studies. However, common lambsquarters control was 68 and 77% for RPA 201772 applied alone at 105 g/ha at Urbana and Brownstown in 1997, respectively, where high common lambsquarters densities were prevalent. Under these conditions, the addition of atrazine to RPA 201772 at 105 g/ha improved control of common lambsquarters. RPA 201772 has excellent potential to provide consistent control of velvetleaf compared with atrazine. In contrast, these studies indicate RPA 201772 may provide inconsistent control of certain weed species in different environments. In order to achieve consistent control of a broad spectrum of weed species, RPA 201772 must be combined with other herbicides.
Weed Management with Reduced Rates of Glyphosate in No-Till, Narrow-Row, Glyphosate-Resistant Soybean (Glycine max)
Authors: Wait Jimmy D. , Johnson William G. , Massey Raymond E.
Published: March 2018

Field studies were conducted at two locations in 1997 and 1998 to evaluate crop injury, weed control, yield, and net economic returns of single and sequential postemergence applications of labeled and reduced rates of glyphosate to no-till, glyphosate-resistant soybean planted in narrow rows. Sequential applications provided at least 91% control of giant foxtail, while single applications provided at least 86% control with labeled rates and 68–93% control with reduced rates. Common waterhemp control was slightly higher with sequential vs. single treatments and with labeled rates vs. reduced rates. Velvetleaf control was greater than 96% with all treatments. Common cocklebur control was 90% or higher with all treatments except a single application of glyphosate at 210 g/ha. Lower control of giant foxtail and common waterhemp with single-application, reduced-rate treatments in two of the four trials resulted in lower yields. Overall, sequential applications, regardless of rate, provided greater weed control, yield, and net income and lower coefficients of variation (C.V.s) of net income than reduced-rate single applications. Single-application treatments showed a trend of decreased weed control, yield, and net income and higher C.V.s of net income with reduced rates of glyphosate.
Basis for Antagonism in Mixtures of Bromoxynil Plus Quizalofop-P Applied to Yellow Foxtail (Setaria glauca)
Authors: Culpepper A. Stanley , York Alan C. , Jordan David L. , Corbin Frederick T. , Sheldon Yvonna S.
Published: March 2018

Antagonism of quizalofop-P efficacy on annual grasses by bromoxynil has been noted in both the field and greenhouse. Laboratory experiments were conducted on yellow foxtail (Setaria glauca) to determine the effect of mixing bromoxynil with the ethyl ester of quizalofop-P on absorption, translocation, and metabolism of14C-quizalofop-P Applying bromoxynil in mixture with quizalofop-P reduced14C-label absorption from 63 to 51%, 73 to 52%, 77 to 68%, and 90 to 80% at 4, 8, 24, and 96 h after treatment, respectively. Translocation of14C-label from the treated leaf into the shoot above or shoot below was unaffected by bromoxynil. However, translocation into the roots was reduced from 0.9 to 0.4% and 1.0 to 0.5% at 4 and 8 h after treatment, respectively, but differences were not noted at 0.5, 1, 24, and 96 h after treatment. Bromoxynil increased deesterification of quizalofop-P-ethyl into quizalofop-P acid from 45 to 60% in the shoot above the treated leaf. However, bromoxynil did not affect metabolism of quizalofop-P in the treated leaf or shoot below the treated leaf. These results suggest that antagonism of quizalofop-P activity by bromoxynil is primarily due to decreased absorption of quizalofop-P, whereas effects on translocation and metabolism were minor.
Evaluation of Several Herbicides for Burcucumber (Sicyos angulatus) Control in Corn (Zea mays)
Authors: Messersmith David T. , Curran William S. , Hartwig Nathan L. , Orzolek Michael D. , Roth Gregory W.
Published: March 2018

A postemergence (POST) timing study was conducted on established populations of burcucumber (Sicyos angulatus) in corn (Zea mays), and a second study examined the residual activity of several herbicides for burcucumber control under greenhouse conditions. In the field study, flumiclorac, halosulfuron, primisulfuron, CGA 152005, and CGA 152005 + primisulfuron (45, 71, 40, 40, and 20 + 20 g ai/ha, respectively) were applied at two POST timings. CGA 152005, primisulfuron, and the combination provided greater than 85% control of burcucumber 14 wk after planting (WAP). Flumiclorac and halosulfuron provided 60% control or less by 8 WAP. Timing of the POST applications did not influence burcucumber control by 11 WAP with any herbicide. In the greenhouse, germinated burcucumber seeds were placed in soil treated with atrazine, chlorimuron, primisulfuron, or CGA 152005 at normal field use rates. All treatments provided similar residual control early; however by 4 wk after treatment (WAT), control from atrazine was less than 10% compared to 69% for chlorimuron and about 50% for primisulfuron and CGA 152005. This research suggests that CGA 152005 and primisulfuron can both be effective for managing burcucumber in corn, whereas flumiclorac and halosulfuron proved ineffective.
Thiazopyr Stimulates Hairy Beggarticks (Bidens pilosa) Germination
Authors: Chandran Rakesh S. , Singh Megh , Salihu Sydha
Published: March 2018

Observations in a citrus grove indicated that hairy beggarticks numbers were higher in plots receiving thiazopyr alone or thiazopyr with oxyfluorfen than in nontreated plots. At 120 days after treatment (DAT), approximately 90% more hairy beggarticks plants had emerged in plots receiving thiazopyr at 0.56 kg ai/ha than in nontreated plots. A tank mix of thiazopyr plus oxyfluorfen, each at 0.56 kg/ha, resulted in a 55% increase in hairy beggarticks number at 120 DAT. Greenhouse studies using seeds collected from sites with or without herbicide history produced similar results. Oxyfluorfen at 0.28 kg/ha stimulated seed germination but injured seedlings by 47% or more at 36 DAT when applied at higher rates. Thiazopyr applied at 0.56 kg/ha antagonized the preemergence activity of oxyfluorfen at 0.28 or 0.56 kg/ha. Thiazopyr at 1.12 kg/ha stimulated hairy beggarticks germination by 37% compared with nontreated containers.
Weed Control and Economics in Nontransgenic and Glyphosate-Resistant Soybean (Glycine max)
Authors: Webster Eric P. , Bryant Kelly J. , Earnest Larry D.
Published: March 2018

A study was conducted in 1996 and 1997 near Rohwer, AR, to evaluate weed control with standard herbicide programs in nontransgenic and glyphosate-resistant soybean (Glycine max) compared with glyphosate-based herbicide programs in glyphosate-resistant soybean. Total postemergence (POST) programs containing 0.84 kg ae/ha glyphosate 14 d after emergence (DAE) followed by 0.42 kg/ha at 42 DAE controlled pitted and entireleaf morningglory (Ipomoea lacunosaandI. hederaceavar.integriuscula) 80 to 83%. This control was lower than with any other weed control program in the study. All glyphosate containing herbicide programs controlled barnyardgrass (Echinochloa crus-galli) at least 94%. Soybean injury was 8% or less for all herbicide treatments except for ‘Hartz 5088 Roundup Ready’ treated with pendimethalin plus chlorimuron and metribuzin preplant incorporated (PPI) followed by glyphosate or acifluorfen plus bentazon 42 DAE. All weed control and soybean injury ratings were similar at 24 d after the 42 DAE application (DAA) when compared with the 10 DAA rating. Two weed control programs with ‘Northrup King S-59-60’ soybean using standard herbicide programs yielded 3,015 and 3,070 kg/ha, and net returns were $92.20/ha and $122.82/ha, respectively. Two production systems containing the Hartz 5088 Roundup Ready cultivar had positive net returns of $35.11/ha and $39.49/ha.
The Cost to the Farmer of Herbicide Resistance
Authors: Orson J. H.
Published: March 2018

A method of calculating the cost to farmers of herbicide resistance in weeds is described along with examples to demonstrate the inherent difficulties and benefits. The main problem is defining cropping systems/practices and herbicide strategies that prevent the development of resistance. The benefits include focusing advisory and research efforts and helping to persuade farmers to adopt practices that prevent the development of resistance.
Nonchemical Options for Delaying Weed Resistance to Herbicides in Midwest Cropping Systems
Authors: Boerboom Chris M.
Published: March 2018

Herbicide-resistant weeds are becoming a major problem in the Midwest, and strategies must be adopted to delay further selection. Strategies of rotating and tank-mixing herbicides with different modes of actions should be effective, but adoption may be limited and certain limitations may exist. Therefore, integrating nonchemical practices that indirectly lower selection pressure or restrict the growth of resistant populations is desirable. Appropriate integration of mechanical weeding, crop rotation, increased crop competition, and decision aids may further delay the development of resistance. Understanding the effect of these practices on weed population dynamics is required to more accurately predict their contributions toward resistance management. This knowledge will aid in justifying the adoption of improved management systems.
Downy Brome,Bromus tectorumL.
Authors: Mitich Larry W.
Published: March 2018

The genusBromusin the Poaceae includes 100 species of annuals, biennials, and perennials. Several species are important as forage crops while others are grown as ornamentals. It is distributed in the temperate areas and in tropical mountainous regions (Hyam and Parkhurst 1995).Bromus tectorumL., downy brome, an introduced annual, occurs throughout most of the U.S., Canada, and northern Mexico (Sheley and Petroff 1999). It was introduced to North America from Europe before 1861. Downy brome has a dual role as a serious weed and as an important forage (Upadhyaya et al. 1986).
“Unhitching the Oxcart of Delhi”: a Mughal-Period Hindi account of Political Insurgency
Authors: BUSCH ALLISON
Published: March 2018

This article is part of a larger effort to broaden the source-base for understanding Mughal-period India by engaging with the Hindi literary archive. I analyze the vignettes of Aurangzeb and other Mughal figures that are available in Lāl Kavi's Chatraprakāś (Light of Chatrasal, c. 1710), a Brajbhasha (classical Hindi) historical poem commissioned by the Bundela ruler Chatrasal (1649–1731). Written shortly after Aurangzeb's death, the Chatraprakāś is in part a retrospective on Aurangzeb's reign. It is also a valuable source of regional history that gives voice to how the Mughal Empire was perceived from a local court that went in and out of political favour. In places, Lāl Kavi engages in trenchant political critique, expressing the court's strong disillusionment with the Mughal manṣabdārī system as well as more local grievances. While by no means the dominant tone of the work, there are occasional hints of the court's outrage at Mughal offenses against what Lal Kavi explicitly terms “Hindu dharma.” Parsing the Chatraprakāś as both poetry and history, I probe the text's complex perspectives on Mughal rule.
Can wild lentil genotypes help improve water use and transpiration efficiency in cultivated lentil?
Authors: Gorim Linda Yuya , Vandenberg Albert
Published: March 2018

Climate change forecasts point to increased frequency of droughts which may affect plant growth. For protein crops such as lentil, genetic improvement of both water use and drought tolerance is necessary. Wild lentil species are known to have evolved in drought prone areas and can be introgressed into cultivated lentil, making them candidates for the evaluation of high transpiration efficiency (TE) and drought tolerance. We assessed TE, water use and drought tolerance at the plant level for five wild lentil species and in cultivated lentil. Under fully watered and moderate drought conditions, wild lentil genotypes consumed significantly less water to fix similar or more dry matter compared with their cultivated counterparts. Under severe drought conditions, the wild lentil genotype L. ervoides IG 72815 had significantly higher TE compared with L. culinaris Eston. Lens ervoides L-01-827A, had significantly higher yield compared with all other species in the presence or absence of drought and showed significantly higher (α = 5%) TE under moderate drought. Drought susceptibility index was identified as a tool to identify drought-tolerant lentil genotypes grown under severe drought. The numerous small seeds of wild lentil made it difficult to estimate drought indices that are weight based and require formulae that incorporate seed numbers.
Preemergence and Postemergence Control of Perilla Mint (Perilla frutescens): Avoiding Toxicity to Livestock
Authors: Russell David P. , Byrd John D. , Zaccaro Maria Leticia M.
Published: March 2018

PRE and POST herbicide options were evaluated to control perilla mint, a potentially deadly plant for livestock. The germination requirements of seed from weedy populations were also investigated to better understand and predict emergence timing. POST applications of aminocyclopyrachlor blends, glyphosate, picloram+2,4-D, aminopyralid+2,4-D, and 2,4-D alone provided superior control of perilla mint when applied in the early reproductive growth stage. Picloram+2,4-D and aminocyclopyrachlor+chlorsulfuron also provided soil residual activity and the most effective PRE control followed by pendimethalin and aminopyralid+2,4-D. Seed from weedy populations tend to germinate in a range of night/day soil temperatures from 10–15 C to 25–30 C. Therefore, application and activation of the most effective PRE treatments should be made before these temperatures occur in areas where weedy perilla mint populations are found.
Some Caves Remove Methane from the Atmosphere, New Tests Reveal
Authors: Shields Laura
Published: March 2018

Isotopic signatures pinpoint the sinks and surprising sources of methane in widespread karst caves. Researchers suggest that this type of cave globally removes more methane than it produces.
MiR34 inhibition induces human heart progenitor proliferation
Authors: Iannolo Gioacchin , Sciuto Maria Rita , Raffa Giuseppe Maria , Pilato Michele , Conaldi Pier Giulio
Published: March 2018

MiR34 involvement in myocardial injury repair and ageing has been well documented in mouse model. Our aim was to establish whether the inhibition of miR34 expression through locked nucleic acid (LNA) could be used as a pharmacological intervention to enhance human heart repair. Cardiac progenitor cells were obtained by right atrial specimen collection during intraoperative procedures. Our analysis revealed a direct correlation between miR34 expression and patient age, and its silencing by LNA promoted the cardiac progenitor growth rate up to twofold ( ± 0.8). Our results confirmed the relevance of miR34a in human heart ageing, as previously demonstrated in mouse. Moreover, the decrease of miR34 expression in the cardiac progenitor cell population indicates its role in maintaining an undifferentiated status and consequently in a lower proliferation rate with the involvement of genes such as Notch-1, Numb, and p63.
Integrated genomics and functional validation identifies malignant cell specific dependencies in triple negative breast cancer
Authors: Patel Nirmesh , Weekes Daniel , Drosopoulos Konstantinos , Gazinska Patrycja , Noel Elodie , Rashid Mamun , Mirza Hasan , Quist Jelmar , Brasó-Maristany Fara , Mathew Sumi , Ferro Riccardo , Pereira Ana Mendes , Prince Cynthia , Noor Farzana , Francesch-Domenech Erika , Marlow Rebecca , de Rinaldis Emanuele , Grigoriadis Anita , Linardopoulos Spiros , Marra Pierfrancesco , Tutt Andrew N. J.
Published: March 2018

Triple negative breast cancers (TNBCs) lack recurrent targetable driver mutations but demonstrate frequent copy number aberrations (CNAs). Here, we describe an integrative genomic and RNAi-based approach that identifies and validates gene addictions in TNBCs. CNAs and gene expression alterations are integrated and genes scored for pre-specified target features revealing 130 candidate genes. We test functional dependence on each of these genes using RNAi in breast cancer and non-malignant cells, validating malignant cell selective dependence upon 37 of 130 genes. Further analysis reveals a cluster of 13 TNBC addiction genes frequently co-upregulated that includes genes regulating cell cycle checkpoints, DNA damage response, and malignant cell selective mitotic genes. We validate the mechanism of addiction to a potential drug target: the mitotic kinesin family member C1 (KIFC1/HSET), essential for successful bipolar division of centrosome-amplified malignant cells and develop a potential selection biomarker to identify patients with tumors exhibiting centrosome amplification.
Development of the social brain from age three to twelve years
Authors: Richardson Hilary , Lisandrelli Grace , Riobueno-Naylor Alexa , Saxe Rebecca
Published: March 2018

Human adults recruit distinct networks of brain regions to think about the bodies and minds of others. This study characterizes the development of these networks, and tests for relationships between neural development and behavioral changes in reasoning about others’ minds (‘theory of mind’, ToM). A large sample of children (n = 122, 3–12 years), and adults (n = 33), watched a short movie while undergoing fMRI. The movie highlights the characters’ bodily sensations (often pain) and mental states (beliefs, desires, emotions), and is a feasible experiment for young children. Here we report three main findings: (1) ToM and pain networks are functionally distinct by age 3 years, (2) functional specialization increases throughout childhood, and (3) functional maturity of each network is related to increasingly anti-correlated responses between the networks. Furthermore, the most studied milestone in ToM development, passing explicit false-belief tasks, does not correspond to discontinuities in the development of the social brain.
Ultrafast optically induced ferromagnetic/anti-ferromagnetic phase transition in GdTiO3 from first principles
Authors: Khalsa Guru , Benedek Nicole A.
Published: March 2018

Epitaxial strain and chemical substitution have been the workhorses of functional materials design. These static techniques have shown immense success in controlling properties in complex oxides through the tuning of subtle structural distortions. Recently, an approach based on the excitation of an infrared active phonon with intense midinfrared light has created an opportunity for dynamical control of structure through special nonlinear coupling to Raman phonons. We use first-principles techniques to show that this approach can dynamically induce a magnetic phase transition from the ferromagnetic ground state to a hidden antiferromagnetic phase in the rare earth titanate GdTiO3 for realistic experimental parameters. We show that a combination of a Jahn–Teller distortion, Gd displacement, and infrared phonon motion dominate this phase transition with little effect from the octahedral rotations, contrary to conventional wisdom.