bluuebunny/crossref_metadata_2025 huggingface dataset:
Creeping Bentgrass (Agrostis palustris) Quality As Influenced by Multiple Low-Rate Applications of Fenoxaprop
Authors: Carroll M. J. , Mahoney M. J. , Dernoeden P. H.
Published: March 2018

Multiple applications of fenoxaprop (0.027, 0.036, and 0.045 kg ai ha–1) were field-applied on either 2-, 3-, or 4-wk intervals to ‘Penncross' creeping bentgrass maintained at putting green height in Easton, MD and Silver Spring, MD during 1989 and 1990. At both locations, yearly averaged creeping bentgrass quality ratings decreased with increasing fenoxaprop rate. Creeping bentgrass discoloration and thinning were minimal at 0.027 kg ha–1fenoxaprop and did not reduce season-long turf quality below acceptable levels at either site in 1989 or 1990. Substantial discoloration and thinning was observed at 0.045 kg ha–1fenoxaprop and acceptable season-long quality was limited to Easton in 1990. Significant spray frequency treatment effects were noticed at both sites in 1989 but not 1990. Increasing the spray interval from 2- to 4-wk improved creeping bentgrass quality from unacceptable to acceptable in two of the final four evaluation dates at Easton and five of the final six dates at Silver Spring.
Postemergence Hemp Sesbania (Sesbania exaltata) Control in Soybean (Glycine max)
Authors: Vidrine P. Roy , Reynolds Daniel B. , Griffin James L.
Published: March 2018

Field studies were conducted at three locations in Louisiana over two years to evaluate mid-season, foliar-applied acifluorfen, fomesafen, and lactofen for hemp sesbania control in soybean. Acifluorfen and fomesafen were applied POST at 30, 40, 50, 60, 70, 140, and 280 g ai ha–1and lactofen was applied at 60, 80, 110, and 220 g ai ha–1. The data fit a quadratic model and log transformations were made to determine differences between treatments. Hemp sesbania control was highly correlated with herbicide rate for each herbicide. Averaged over rates of application, acifluorfen and fomesafen provided equivalent control of hemp sesbania, which was greater than that achieved with lactofen. The minimum effective rate of acifluorfen or fomesafen for 80 and 100% control of 50- to 60-cm hemp sesbania was 50 and 140 g ha–1, respectively. The minimum effective lactofen rate to provide at least 80% control was 220 g har–1.
Phytotoxicity of Chlorimuron and Tank Mixtures on Peanut (Arachis hypogaea)
Authors: Johnson W. Carroll , Mullinix Benjamin G. , Brown Steven M.
Published: March 2018

Studies were conducted in 1989 and 1990 to determine the phytotoxicity of chlorimuron and tank mixtures on ‘Florunner’ peanut. Chlorimuron plus a petroleum oil adjuvant or 2,4-DB was more phytotoxic (P = 0.05) than chlorimuron plus a nonionic surfactant, based on stunting and chlorosis. Chlorimuron mixed with chlorothalonil, chlorothalonil plus sulfur, or esfenvalerate were no more phytotoxic than the standard. Adding sulfur or nonionic surfactant to chlorimuron plus chlorothalonil did not affect phytoxicity. Sequential applications of chlorimuron and 2,4-DB did not completely negate the phytotoxicity of the tank mixture. Despite differences in phytotoxicity, yields were not reduced.
Integration of Cereal Cover Crops in Ridge-tillage Corn (Zea mays) Production
Authors: Eadie Allan G. , Swanton Clarence J. , Shaw James E. , Anderson Glen W.
Published: March 2018

Field experiments evaluating 11 cereal cover crops were established at two locations in Ontario over a two-year period. Cover crops were interseeded into a ridge-tillage corn crop and evaluated in terms of biomass production and winter annual, biennial, and perennial weed species suppression. Seedling establishment and aboveground biomass production of cover crops were variable between locations and years. At both locations over two years, ‘Danko’ winter rye, ‘OAC Halton’ winter barley and ‘Rodeo’ spring barley were the most consistent cover crops in biomass production. However, cover crop residues had no significant effect on weed biomass or density due to a high degree of spatial variability present in the weed populations. Corn grain yields were not reduced by the presence of inter-seeded cover crops when compared with the bare ground control treatment.
Sericea Lespedeza (Lespedeza cuneata) Control with Selected Postemergence Herbicides
Authors: Altom John V. , Stritzke Jimmy F. , Weeks David L.
Published: March 2018

Field experiments were conducted in the summers of 1988 and 1989 to evaluate sericea lespedeza control with POST herbicides. Triclopyr, picloram, 2,4-D, metsulfuron, dicamba, and selected herbicide mixtures were evaluated in 1988 and 1989. Clopyralid was evaluated in 1988 and fluroxypyr in 1989. Triclopyr at 0.56 and 1.12 kg ha–1controlled sericea lespedeza both years. Fluroxypyr at 0.56 kg ha–1also controlled sericea lespedeza. Control with picloram and metsulfuron was variable. Other treatments evaluated did not control sericea lespedeza.
An Industry Perspective on Herbicide-Tolerant Crops
Authors: Giaquinta Robert T.
Published: March 2018

Technology is now available to create herbicide-tolerant crops. This technology, when combined with environmentally and toxicologically sound herbicides and when used wisely in an integrated weed management program, can contribute positively to crop production. However, it is unlikely that herbicide-tolerant crops will revolutionize weed management. Instead, they will complement existing weed management practices and provide additional options to growers. Adoption and success of herbicide-tolerant crops will be dependent on several technical, environmental, business, economic, and societal issues. Industries that are developing herbicide-tolerant crops need to openly communicate and discuss both the value that their technology brings to agriculture and society and the strategies for ensuring its responsible use.
Combining Computer Simulation with Physical Simulation: An Attempt to Validate Turf Runoff Models
Authors: Lin James C. , Graney Robert L.
Published: March 2018

Predicting the off-target movement of agrochemicals applied to turf is an essential component for assessing risk to aquatic environments. For surface transport, a fully validated model does not exist. Such a model is required to make cost effective risk assessments and regulatory evaluations. To address this deficiency, a turf model validation program is outlined in this paper. The effect of turf characteristics on the fate and movement of pesticides is presented followed by the discussion of the selection for a proper turf runoff model. The design and implementation of small plot runoff studies and their usefulness in model validation are discussed. The procedures of model calibration and model verification are explained for model validation purpose.
Computer Models for Fate Assessment During the Registration Process: Data Needs
Authors: Behl Elizabeth
Published: March 2018

Computer models designed to simulate the fate and transport of pesticide residues in surface runoff and water that recharges shallow aquifers are used at several stages in the regulation of pesticides. Models can be a powerful tool to identify environments in which pesticides are more mobile and are more likely to impact ground-water quality. Models can also be used to highlight pesticides that can contaminate surface or ground water at an early stage of the registration process. At present, models are utilized primarily as comparative tools to identify which compounds should be examined on a priority basis. Results may be used to calibrate numerical models and estimate the long term impact on the environment from the use of a particular product or its alternatives. To date, field monitoring studies have been required for over 40 chemicals by the Office of Pesticide Programs (OPP) to evaluate the leaching potential of pesticides under realistic usage conditions. As the capabilities of models improve and linkages are developed between databases and the models, computer simulation models will play an increasingly important role in the Environmental Protection Agency's (EPA's) efforts to manage pesticide use to prevent adverse effects on the environment.
Screening Procedure for Soils and Pesticides for Potential Water Quality Impacts
Authors: Goss Don W.
Published: March 2018

A screening procedure has been developed to evaluate the relative loss of pesticides from soils, to assist the Soil Conservation Service in implementing water quality for conservation planning. This screening procedure is a first-tier evaluation of the impact of using a particular pesticide on a specified soil. The screening procedure was developed from evaluating pesticide loss from over 40 thousand runs of the GLEAMS (Groundwater Loading Efects of Agricultural Management Systems) model. The model input data were a combination of soils and pesticides with a wide range of properties. The estimated pesticide losses were categorized into losses by leaching, losses adsorbed on sediment in runoff, and losses in the solution phase of runoff. Algorithms using soil properties were developed to rate soils into four loss potential classes for leaching and three loss potential classes for the two categories of runoff. Also, algorithms using pesticide properties were developed to rate pesticides into four loss potential classes for leaching and three loss potential classes for runoff. The soil and pesticide groupings are combined in a matrix to give an overall loss potential rating. Statistics of the overall loss potential indicate the low loss potential class is pure, that is, it does not contain occurrences that have medium or high losses. The medium loss potential classes does not contain occurrences of high loss, but does contain many occurrences of low loss. The high loss potential class contains incidences of medium and low loss.
Cotton (Gossypium hirsutum) Response to Clomazone and Insecticide Combinations
Authors: York Alan C. , Jordan David L.
Published: March 2018

An experiment was conducted at four locations during 1990 and 1991 to determine the response of cotton to 1.12 kg ai ha-1 of clomazone applied PPI in combination with in-furrow application of 0.50 kg ai ha-1 of aldicarb plus 0.14, 0.28, and 0.56 kg ai ha-1 of either disulfoton or phorate. Early-season cotton injury ranged from 15 to 63% with clomazone plus aldicarb. Stands were reduced 31 and 61% at two locations, and yield was reduced 50% at one location. Applied in combination with aldicarb, all three rates of disulfoton and 0.28 and 0.56 kg ha-1 of phorate protected cotton from clomazone injury. Phorate at 0.14 kg ha-1 partially protected cotton from clomazone injury.
Common Cocklebur (Xanthium strumarium) Control with Reduced Rates of Soil and Foliar-Applied Imazaquin
Authors: Griffin James L. , Reynolds Daniel B. , Vidrine P. Roy , Saxton Arnold M.
Published: March 2018

Field studies were conducted to evaluate common cocklebur control in soybean with imazaquin applied preplant incorporated (PPI), preemergence (PRE), and postemergence (POST) at rates ranging from 24 to 140 g ai ha-1. With logistic regression analysis, predictions of common cocklebur control with imazaquin at 140 g ha-1ranged from 92 to 95% (PPI), 87 and 92% (PRE), and 88 to 98% (POST) when rainfall was received for activation of PRE treatments and when weeds were not moisture stressed at time of POST application. When imazaquin was reduced to 70 g ha-1under the same conditions, weed control was no higher than 88% PPI and 78% PRE. For all locations and years, common cocklebur control ranged from 79 to 91% for imazaquin POST at 24 g ha-1. Soybean yield was positively correlated with common cocklebur control (r = 0.66, P < 0.05).
Woolly Morningglory (Ipomoea hirsutula) as a Weed-Taxonomic Clarification
Authors: Elmore C. Dennis , Schroeder Jill
Published: March 2018

Collections of woolly morningglory from New Mexico were determined to be tall morningglory (Ipomoea purpurea) or, in some cases, ivyleaf morningglory (I. hederacea) by misapplication. Woolly morningglory is a variant of tall morningglory with lobed leaves known asI. purpureavar.diversifoliaby some sources, although modern taxonomists consider this variant to be undeserving of variety rank.
Influence of Preemergence and Postemergence Herbicides on Rooting of Turfgrasses
Authors: Landschoot Peter J. , Watschke Thomas L. , Hoyland Bryce F.
Published: March 2018

PRE and POST herbicides were evaluated for their effects on root growth of Kentucky bluegrass and tall fescue turf. All PRE treatments, bensulide at 14.0 kg ai ha−1, DCPA at 11.8 kg ha−1, dithiopyr at 0.4 kg ha−1, pendimethalin at 1.7 kg ha−1, and prodiamine at 0.6 kg ha−1, inhibited root growth when cores, 10 cm in diam and 2.5 cm deep, of herbicide-treated Kentucky bluegrass were placed into pots of perlite. Only prodiamine inhibited tall fescue rooting. None of the PRE treatments reduced rooting of grasses when 10-cm diam and 16-cm deep cores were sampled from the field. No differences in rooting were observed among any of the POST treatments on either species.
Inhibition of Downy Brome (Bromus tectorum) Root Growth by a Phytotoxin fromPseudomonas fluorescensStrain D7
Authors: Tranel Patrick J. , Gealy David R. , Kennedy Ann C.
Published: March 2018

Field applications of the rhizobacterium,Pseudomonas fluorescensstrain D7 (D7), have selectively suppressed downy brome in winter wheat test plots. A phytotoxin produced by D7 inhibits downy brome root growth. An assay system was developed for future investigations of the mechanism of action of this and other phytotoxins that inhibit root growth. A crude preparation of the phytotoxin, cell-free supernatant (CFS), had little activity on downy brome root elongation in a sand-petri plate system. CFS was very active in a hydroponic system, in which a 6% (v/v) concentration inhibited root elongation within 1.5 h. Inhibition of root elongation was reversible in this system. Root elongation of downy brome seedlings resumed within 3 h after removal from a 9-h incubation in 8% CFS. CFS from genetic variants of D7 did not substantially inhibit root growth and a semi-crystallized precipitation product from D7 CFS inhibited root growth similarly to D7 CFS, indicating that the phytotoxin present in the CFS was responsible for growth inhibition.
Interactions of Fenoxaprop-ethyl with Fenchlorazole-ethyl in Annual Grasses
Authors: Stephenson Gerald R. , Tal Abraham , Vincent Norman A. , Hall J. Christopher
Published: March 2018

In growth room studies, POST applications of fenoxaprop-ethyl at 50 g ai ha−1 at the four- to five-leaf stage of development were non-toxic to barnyardgrass, large crabgrass, and yellow foxtail. POST applications of fenchlorazole-ethyl at 12.5 or 25.0 g ai ha−1 were also nontoxic to these same three species. However, when the two chemicals were applied in combination at the above rates they were toxic to all three species, indicating a synergistic interaction in all three species. In additional studies, a sensitive biotype of wild oat was severely injured by fenoxaprop-ethyl at 50 g ai ha−1 and a resistant biotype of wild oat was only slightly injured by fenoxaprop-ethyl at rates as high as 800 g ai ha−1. However, no significant interactions were observed between fenoxaprop-ethyl and fenchlorazole-ethyl in either of these wild oat biotypes.
Kikuyugrass (Pennisetum clandestinum) Management in Turf
Authors: Cudney David W. , Downer James A. , Gibeault Victor A. , Henry J. Michael , Reints John S.
Published: March 2018

Kikuyugrass is an invasive, perennial weed of turf-grass in California. Currently, complete renovation of infested turf is the most practical means of control. A less disruptive method was needed to reduce the competitive ability of kikuyugrass while allowing the regrowth of desirable turf species. Treatment with MSMA, triclopyr, and quinclorac did not control kikuyugrass as single applications, but when applied at 4- to 5-wk intervals over a 5-mo period, kikuyugrass was reduced. Sequential applications of two-way combinations of these herbicides in 1991 resulted in reductions of kikuyugrass from 80% to less than 1% of the sward.
Chicory
Authors: Mitich Larry W.
Published: March 2018

Chicory (Cichorium intybus L. # CICIN), succory, blueweed, coffee-weed, blue sailors, bunk, or blue daisy, is familiar to many of us as an erect weed along roadsides or in fields, displaying small, startlingly bright blue flowers. Others of us may only have tasted its roots—roasted and ground into a bittersweet coffee substitute or additive: an essential component of the New Orleans brew served blacker than a hundred midnights in a cypress swamp. Along with its close relative endive (Cichorium endivia L.), chicory also has an important place in the salads of Europe and, increasingly, the United States. Both chicory and endive were indispensable in ancient and medieval herbal pharmacies and are still used medicinally today.
Imazaquin, Chlorimuron, and Fomesafen May Injure Rotational Vegetables and Sunflower (Helianthus annuus)
Authors: Johnson David H. , Talbert Ronald E.
Published: March 2018

Carryover potential of imazaquin (0.14 kg ai ha−1), chlorimuron plus metribuzin (0.06 + 0.36 kg ha−1), and fomesafen (0.28 kg ha−1) to snap bean, watermelon, cucumber, mustard, and sunflower was evaluated in Arkansas in 1987 to 1989. Crops were direct-seeded into treated plots at various times after application. Imazaquin and chlorimuron plus metribuzin injured sunflower, watermelon, cucumber, and mustard when planted 16 wk following application in one of two years. Fomesafen injured all crops initially but did not injure snap bean, sunflower, watermelon, and cucumber planted 16 wk after application. In experiments in which herbicides were applied to soybean, fall-planted spinach and mustard were injured in one of two years.
Oxyfluorfen Under Clear Polyethylene Film Controlled Weeds in Transplanted Cucurbits
Authors: Bellinder Robin R. , Binning Larry K. , Yourstone Kenneth S. , Bonanno A. Richard , Gorski Stanley F. , Majek Bradley A. , Neary Phillip E. , Baron Jerry J. , Holmdal Jay , Wallace Russell W.
Published: March 2018

Oxyfluorfen (0.28, 0.42, 0.56, and 0.84 kg ai ha−1) under clear polyethylene film was evaluated for weed control, crop injury, and effects on yields in transplanted muskmelon, cucumber, and summer squash. Numerous narrowleaf and broadleaf weeds were effectively suppressed by 0.42 ha−1of oxyfluorfen. Crop injury, occurring soon after transplanting, was reported in New York and North Carolina. Injury was usually transient, and injured crops frequently grew more vigorously than those grown on untreated black polyethylene mulch. Muskmelons were consistently the most tolerant of the three crops. At high rates, yields of squash and cucumber in 1988 were reduced in New York and North Carolina, respectively. In greenhouse studies, positioning the cotyledons under the polyethylene film caused greater injury in all three crops than when cotyledons remained above the plastic.
Nicosulfuron, Primisulfuron, Imazethapyr, and DPX-PE350 Injury to Succeeding Crops
Authors: Johnson David H. , Jordan David L. , Johnson William G. , Talbert Ronald E. , Frans Robert E.
Published: March 2018

Nicosulfuron (50 and 100 g ai ha−1), primisulfuron (40 and 80 g ai ha−1), imazethapyr (70 and 140 g aiha-1), and DPX-PE350 (100 and 200 g aiha-1) injury to corn, cotton, grain sorghum, rice, and soybean was evaluated at Fayetteville, AR, during 1989-90 and 1990-91. The crops were planted 0, 1, 2, 4, 8, 14 or 16, and 52 wk after herbicide application. Visible injury to all crops declined as the time interval increased. No visible injury was observed to any crop planted at least 14 wk after nicosulfuron or primisulfuron application, or 52 wk after DPX-PE350 application. Imazethapyr injured all crops except soybean at the 52-wk interval in 1990 but not in 1989.
Use of Activated Carbon to Reduce Phytotoxicity of Imazaquin to Tobacco (Nicotiana tabacum)
Authors: Yelverton Fred H. , Worsham A. Douglas , Peedin Gerald F.
Published: March 2018

In 1987-89, field experiments were conducted to evaluate rates of activated carbon in transplant water to reduce injury to tobacco from imazaquin. Rates of activated carbon were 0, 2.2, 4.5, and 9 kg ha−1in 1987 and 0, 9, 18, and 36 kg ha−1in 1988-89. Imazaquin rates were 0, 0.3, and 0.6 kg ha−1applied over-the-top immediately after transplanting. Results indicated that 9 kg ha−1of activated carbon was the minimum amount to reduce injury from imazaquin. No additional protection was achieved with rates above 9 kg ha−1, whereas lower rates appeared to offer less protection based on visible stunting ratings.
Control of Downy Brome (Bromus tectorum) and Volunteer Wheat (Triticum aestivum) in Fallow with Tillage and Pronamide
Authors: Ogg Alex G.
Published: March 2018

Field studies were conducted in 1986-87 and 1988-89 to compare chiseling, disking, and skewtreading to no-till and to compare 0.3 and 0.4 kg ai ha−1pronamide applied before or after fall tillages for weed control in fallow. Chiseling or disking in October 1986 when weeds were emerged reduced the dry weight of volunteer wheat about 90% the following spring; however, only disking reduced the dry weight of downy brome 90%. Disking or skewtreading in October 1988 before weeds germinated reduced the dry weight of volunteer wheat about 95% 6 mo later, but none of the three tillages reduced the dry weight of downy brome. Pronamide applied at 0.3 and 0.4 kg ha−1to emerged downy brome and volunteer wheat with either chiseling or disking before or after herbicide application reduced the dry weight of both species 90% or more 6 mo later compared with tillage alone. If weeds did not emerge until early November, then only pronamide at 0.4 kg ha−1applied in no-till or after fall tillage controlled both species at least 90%.
Tropical Soda Apple (Solanum viarum) Control
Authors: Mullahey J. Jeffrey , Cornell John A. , Colvin Danny L.
Published: March 2018

Hexazinone (1.12 kg ai/ha), triclopyr (1.12 kg ai/ha), metsulfuron (0.008 kg ai/ha), dichlorprop + 2,4-D, glyphosate (2.8%), and triclopyr (2%) + diesel oil (98%), applied as a broadcast or spot (individual plant) treatment, were evaluated over two years in south Florida for tropical soda apple (TSA) control and their effects on grass ground cover. For broadcast treatments, triclopyr (98%) and hexazinone (93%), had significantly (P < 0.05) higher percent control of marked TSA plants 90 d after herbicide application. However, triclopyr (99%) had significantly higher grass ground cover than hexazinone (78%). Hexazinone severely damaged Pangola digitgrass, but had no effect on bahiagrass. For spot treatments, dichlorprop + 2,4-D (100%) had the highest percent total control of TSA and least effect on grass ground cover (96%) 90 d after herbicide application, followed by glyphosate (96% control) and triclopyr + diesel oil (95% control). Based on acceptable (>90%) TSA control and grass ground cover, triclopyr broadcast or dichlorprop + 2,4-D spot provided the greatest control. With either application method, repeated herbicide applications will be necessary to eliminate TSA because of rapid seedling emergence following control of existing plants.
Effect of Preplant Tillage, Post-Plant Cultivation, and Herbicides on Weed Density in Corn (Zea mays)
Authors: Wilson Robert G.
Published: March 2018

A four-year experiment was conducted near Scottsbluff, NE to evaluate the effect of different methods of preplant tillage, post-plant cultivation, and herbicides on weed density and grain yield. Ridge-till enhanced the development of kochia and reduced the density of wild proso millet and common lambsquarters. Tandem disking increased longspine sandbur and redroot pigweed density whereas moldboard plowing increased common sunflower density. Cultivation reduced weed density 86% but weeds that remained after cultivation reduced corn grain yield by 40% as compared with a hand-weeded control. Weed control treatments that integrated cultivation and herbicides controlled a broader spectrum of weed species than cultivation or herbicide treatments alone.
Soybean (Glycine max) Tolerance to Simulated Drift of Nicosulfuron and Primisulfuron
Authors: Bailey John A. , Kapusta George
Published: March 2018

Soybean response to simulated drift of the corn herbicides nicosulfuron and primisulfuron applied POST at 10 to 50% (3.5 to 17.4 and 4.0 to 20.2 g ai ha−1, respectively) of the total rates at the V3 and R1 growth stages was evaluated in field studies in 1991 and 1992. Primisulfuron reduced soybean height and increased leaf chlorosis, cupping, and necrosis more than nicosulfuron with both applications at all five rates. The symptoms of injury caused by both herbicides often increased linearly with increasing rate. At 50% of label rate, primisulfuron reduced height 75% and decreased yield 58%. Nicosulfuron reduced soybean height as much as 27%, but did not reduce seed yield either year. Height reduction, leaf chlorosis, cupping, and necrosis were correlated with yield loss caused by primisulfuron.
Survey Results on Environmental Issues and Weed Science Research Priorities within the Corn Belt
Authors: Stoller Edward W. , Wax Loyd M. , Alm David M.
Published: March 2018

A survey determined the views of individuals in seven groups comprising the weed science community in the corn belt (primarily in Illinois) for importance of 8 environmental and 14 crop production issues and 16 weed species in setting weed science research priorities for the next 3 to 5 yr. The survey also considered if funding of research to solve these environmental and production issues should be from the private or public sector. Velvetleaf, foxtail species, and common lambsquarters were considered the top three weed species by all respondents, and each of these weeds was among the five most important weeds within each of the seven survey groups. Improving ground and surface water quality were the foremost environmental issues for all respondents, but soybean growers listed herbicide carryover as their top environmental concern. Reducing herbicide residues in food and developing sustainable practices were given low preference by all groups. Sustainable growers rated reducing herbicide carryover and minimizing applicator exposure as their lowest priorities. Among all respondents, the top three production issues were improved weed control in conservation tillage, more economical weed control, and improved integrated control strategies. Studying the biology/life cycles of weeds was the third highest production priority of University and U.S. Department of Agriculture (USDA) weed scientists, but was the last choice when averaged over the aggregate survey group. Developing strategies for resistant weeds and herbicide-resistant crops were chemical dealers top two priorities. Industry representatives gave the former subject their highest rating and the latter their lowest rating. Crop consultants seemed to want decision aids, as they chose assessing weed loss/thresholds and developing weed control/economic models among their top three production issues. Both corn and soybean growers desired more economical weed control as a first choice, while sustainable growers wanted improved cultural control strategies. Corn and soybean growers ranked developing new herbicides among their top three choices, but this issue was the lowest choice of the sustainable growers. University, USDA, and industrial weed scientists suggested that their own organizations conduct the research on their highest priorities issues.
Effects of Paraquat and Alachlor on Peanut (Arachis hypogaea) Growth, Maturity, and Yield
Authors: Johnson W. Carroll , Chamberlin Joseph R. , Brenneman Timothy B. , Todd James W. , Mullinix Benjamin G. , Cardina John
Published: March 2018

Studies were conducted in 1988, 1989, and 1992 in Plains, GA to measure effects of paraquat and alachlor on ‘Florunner’ peanut. Peanut treated with paraquat (0.14 kg ai/ha) plus alachlor (3.4 kg ai/ha) applied at vegetative emergence (VE), or paraquat plus alachlor VE followed by paraquat 28 days after emergence (DAE) were compared with a nontreated control. Both herbicide treatments reduced peanut foliage biomass at 65 DAE in 1989 and 1992. Herbicide treatments did not affect foliage biomass 90 DAE in 1988 and 122 DAE in 1989, but paraquat plus alachlor followed by paraquat reduced foliage biomass at 122 DAE in 1992. Pod biomass, measured at 90 and 65 DAE in 1988 and 1992, respectively, was reduced by herbicides. However, pod biomass did not differ among treatments 122 DAE in 1989 and 1992. Percent reflectance from the peanut canopy measured no effects from herbicides in 1988. However, in 1989 and 1992 herbicides applied sequentially reduced peanut canopy development. Peanut treated with a single herbicide and sequentially took longer to mature. Once optimum maturity was reached, peanut yields were not reduced.
Seaweed Extract and Alginates as Adjuvants with Sethoxydim
Authors: Taylor John S. , Harker K. Neil , Robertson J. Mason
Published: March 2018

Experiments were conducted in the greenhouse and the field to determine if a seaweed extract and its component alginates could enhance the activity of sethoxydim on barley (five- to six-leaf stage). In greenhouse trials, sethoxydim with 0.5% oil concentrate was applied at 0.05, 0.1, and 0.15 kg ai/ha; in field trials, sethoxydim with 0.5% oil concentrate was applied at 0.1, 0.2, and 0.3 kg/ha. In both sets of trials the seaweed extract was applied at a rate of 1 and 2 L/ha, and the alginates were applied at 250 and 500 g/ha. When either the seaweed extract, or the calcium ammonium salt of alginic acid was used as an adjuvant a significant increase in sethoxydim activity was usually observed. At the highest rates of these adjuvants, sethoxydim (0.2 kg/ha) activity increased from 59% control (1321 g/m2fresh weight) with only oil concentrate, to 87% control (224 g/m2fresh weight) with seaweed extract, or 89% control (184 g/m2fresh weight) with the calcium ammonium salt of alginic acid. Sodium salts of alginic acid, both low and medium viscosity, were much less effective.
Effects of DPX PE350 on Cotton (Gossypium Hirsutum) Growth, Yield, and Fiber Quality
Authors: Keeling J. Wayne , Henniger C. Gary , Abernathy John R.
Published: March 2018

DPX PE350, an experimental herbicide, has shown excellent potential for controlling a wide range of problem broadleaf weeds in cotton. PPI, PRE, and POST applications of DPX PE350 at 0.1 and 0.2 kg ai/ha were evaluated under weedfree conditions in 1991 and 1992 for effects on ‘Paymaster HS26’ cotton growth, yield, and fiber quality. In 1991, DPX PE350 applied PPI, PRE, or POST did not affect cotton population, height, yield, or fiber quality. In 1992, DPX PE350 applied PPI at 0.1 or 0.2 kg/ha or PRE at 0.2 kg/ha injured the cotton and reduced yield and micronaire value.
In-Furrow Terbufos Reduces Field and Sweet Corn (Zea mays) Tolerance to Nicosulfuron
Authors: Morton Cathy A. , Harvey R. Gordon , Kells James J. , Landis Douglas A. , Lueschen William E. , Fritz Vincent A.
Published: March 2018

Field experiments were conducted in Michigan, Minnesota, and Wisconsin in 1990 to explore interactions between nicosulfuron applied POST and terbufos insecticide at 0.06 or 0.11 g ai/m of row applied in-furrow on ‘Pioneer 3751’ field corn and ‘Jubilee’ sweet corn. Nicosulfuron at 0, 70, and 140 g ai/ha plus nonionic surfactant and 28% nitrogen fertilizer was applied to both corn types. Field corn response to nicosulfuron and terbufos was similar at all locations, whereas sweet corn injury varied with location. Nicosulfuron injured field corn more when applied at the four-leaf than the three-leaf stage. Injury to both corn types increased as nicosulfuron rate increased or when applied following terbufos. Nicosulfuron at 140 g/ha without terbufos did not reduce yield of either corn type; however, corn previously treated in-furrow with terbufos reduced yield.
Crop Response to Fallow Applications of Atrazine and Clomazone
Authors: Lyon Drew J. , Anderson Randy L.
Published: March 2018

The response of oat, foxtail millet, proso millet, and sunflower to atrazine and clomazone applied the previous fall was investigated two years in field studies near Akron, CO and Sidney, NE. Foxtail millet biomass, and proso millet and sunflower grain yields were not reduced when these crops were seeded into soil that had been treated the previous fall with atrazine and/or clomazone at rates of 0.6 or 1.1 kg ai/ha. Forage yield of oat was reduced 11 to 18% by some treatments, but this effect was not consistent over years or sites. Treatments containing 1.1 kg/ha of atrazine provided 1 to 5 wk of residual weed control in foxtail millet, proso millet, and sunflower. The study indicated that producers have flexibility in crop selection when using atrazine and clomazone in reduced- and no-till production systems.
Effect of Soil Moisture on Atrazine and Cyanazine Persistence and Injury to Subsequent Cereal Crops in Southern Alberta
Authors: Moyer Jim R. , Blackshaw Robert E.
Published: March 2018

One year after application under irrigated conditions, atrazine at 1.2 kg/ha injured oat but there was no effect after two years. On dryland, wheat and barley were injured for up to two years after atrazine was applied at 1.5 kg/ha. Atrazine concentrations in the soil were related to accumulated rainfall in an exponential equation. The equation predicted that, under the most severe drought conditions ever recorded for southern Alberta, injury to cereal crops could occur for at least three years after atrazine application at 1.2 to 1.5 kg/ha. Cyanazine did not injure subsequent crops under either irrigated or dryland conditions.
Interaction of Metribuzin and Phorate on ‘Atlantic’ and ‘Norchip’ Potato (Solanum tuberosum) Cultivars
Authors: Hatterman-Valenti Harlene , Lawson Vince F. , Owen Micheal D. K.
Published: March 2018

The effects of metribuzin herbicide and phorate insecticide were studied on summer harvest chipping-potatoes at Muscatine, IA, from 1989 to 1991. Phorate at 1.5 kg/ha increased total and ‘A’-size tuber yield and tuber specific gravity. Metribuzin applied at 0.56 kg/ha postemergence decreased total and ‘A’-size tuber yield. Metribuzin applied at 0.56 kg/ha preemergence and 0.28 kg/ha postemergence did not reduce Atlantic cultivar yield. Metribuzin did not affect ‘B’-size tuber yield or specific gravity. Phorate in combination with metribuzin did not increase plant injury or reduce tuber yield.
Chemical and Mechanical Control of Dogfennel (Eupatorium capillifolium)
Authors: Macdonald Gregory E. , Brecke Barry J. , Colvin Daniel L. , Shilling Donn G.
Published: March 2018

In field studies effective dogfennel control was obtained with glyphosate, dicamba + 2,4-D, triclopyr + 2,4-D, and fluroxypyr at rates of 1.68, 0.44 + 1.25, 0.56 + 1.12, and 0.28 kg ai/ha, respectively, applied after dogfennel was 75 cm tall. Mowing alone reduced dogfennel regrowth by 81% and when combined with dicamba + 2,4-D or triclopyr + 2,4-D regrowth was reduced over 94%. Triclopyr, dichlorprop, and sulfometuron also controlled dogfennel greater than 90% but metsulfuron did not.
Puccinia punctiformisAffects Growth and Reproduction of Canada Thistle (Cirsium arvense)
Authors: Thomas Rosemary F. , Tworkoski Thomas J. , French Richard C. , Leather Gerald R.
Published: March 2018

In growth chamber research, infection byPuccinia punctiformis, a rust fungus, reduced flowering and vegetative reproduction in Canada thistle. Disease symptoms were greatest when Canada thistle roots were stored at 5, 10, or 15 C following inoculation. Exposure of roots to different temperatures before inoculation did not affect disease. All Canada thistle clones tested, regardless of gender became diseased although there were differences in susceptibility toP. punctiformis.
Unrefined Corn Oil Improves the Mycoherbicidal Activity ofColletotrichum truncatumfor Hemp Sesbania (Sesbania exaltata) Control
Authors: Boyette C. Douglas
Published: March 2018

In greenhouse experiments, unrefined corn oil was tested as an adjuvant with the mycoherbicidal fungus,Colletotrichum truncatum.A1:1 (V/V) fungus/corn oil tank mixture extended by at least 70 h the period of time in which the fungus remains infective between inoculation and the onset of dew. This formulation also reduced the dew period requirements for optimal weed pathogenesis and mortality from 12 h to 2 h, and reduced the required spray volume by 100-fold, from 500 L/ha to 5 L/ha. These results suggest that formulatingC. truncatumin unrefined corn oil greatly improves the bioherbicidal potential of this pathogen.
Integrated Weed Control Management in Soybeans (Glycine max) in Greece
Authors: Vizantinopoulos Spyros , Katranis Nikos
Published: March 2018

Field experiments were conducted in 1988, 1989, and 1990 in Greece to investigate the combination of cultural and chemical methods for weed control in soybean. The selectivity of herbicides or the combination of herbicides used was dependent on application rate. Imazaquin applied PRE was selective on soybean even at 0.18 kg/ha, whereas imazethapyr was safer on soybean than imazaquin at 0.22 kg/ha. Metribuzin at 0.37 kg/ha tank-mixed with alachlor, metolachlor, imazaquin, and SAN 582H were not phytotoxic at their recommended rates. All herbicides satisfactorily controlled the weeds in the experiments. The early-season period threshold level for a mixed population ofAmaranthusspp. occurred 3.0 to 3.5 wk after weed emergence. Density ofAmaranthusspp. of about 270 to 470 plants/m2caused soybean yield reduction equal to 11 to 35%, respectively. The treatments did not influence the oil content of the soybean seed but in one experiment the protein content was influenced slightly by some of the treatments. The results emphasize the importance of using chemical, cultural, and competition threshold levels of cultural practices for an integrated approach for weed control in soybean.
Propanil-Resistant Barnyardgrass (Echinochloa crus-galli) Control in Rice (Oryza sativa)
Authors: Baltazar Aurora M. , Smith Roy J.
Published: March 2018

Six experiments were conducted in three rice fields near Harrisburg, AR in Poinsett County in 1991 and 1992 to confirm barnyardgrass resistance to propanil and to compare herbicide treatments for control of propanil-resistant barnyardgrass. In all experiments, standard treatments of thiobencarb applied delayed PRE or tank mixtures of propanil + thiobencarb applied POST controlled propanil-resistant barnyardgrass. In five of six experiments, propanil failed to control barnyardgrass at 6 to 8 kg ai/ha (three times use rates) and in three experiments it provided inconsistent control at 11 kg/ha. Emulsifiable propanil at 11 kg/ha frequently controlled resistant barnyardgrass better than the dry flowable formulation. Treatments that consistently controlled propanil-resistant barnyardgrass included propanil tank-mixed with pendimethalin or quinclorac applied POST to two-leaf grass; quinclorac applied alone delayed PRE or POST or applied POST tank-mixed with thiobencarb, pendimethalin, or a formulated mixture of molinate and propanil; a formulated mixture of propanil and molinate applied POST in tank mixtures with thiobencarb or pendimethalin; and fenoxaprop or fenoxaprop-P alone applied POST to four-leaf grass prior to flood establishment. Herbicide treatments that failed to control resistant barnyardgrass included POST applications of a formulated mixture of propanil and molinate alone and propanil in tank mixtures with bromoxynil or triclopyr. These studies confirm that barnyardgrass from several farms in Arkansas have resistance to propanil and identified treatments that control propanil-resistant barnyardgrass.
Effects of Rain-Free Intervals and Herbicide Rate on Sicklepod (Cassia Obtusifolia) Control and Absorption with AC 263,222
Authors: Newsom Larry J. , Shaw David R.
Published: March 2018

Experiments were conducted to evaluate the effect of a 2.5-cm simulated rainfall 0.05, 0.25, 0.5,1, 3, 6, and 24 h after POST applications of AC 263,222 to sicklepod. Fresh weight reductions were directly related to increasing AC 263,222 rates and rain-free intervals. Fresh weight reductions with 9, 18, 36, 54, and 72 g ai/ha AC 263,222 were 32, 47, 55, 59, and 67%, respectively, with the rain-free treatment. A simulated rainfall 0.05 h after POST application lowered fresh weight reductions with 9, 18, 36, 54, and 72 g/ha AC 263,222 to 5, 7, 19, 23, and 28%, respectively, of the untreated control. As AC 263,222 rates increased, a simulated rainfall shortly after POST application was less detrimental. At 18 g/ha of AC 263,222, a 3-h rain-free interval was necessary for fresh weight reductions equivalent to the rain-free control. As the rate of AC 263,222 increased to 54 g/ha, the rain-free interval for fresh weight reductions equivalent to the rain-free control was reduced to 1 h. Radiolabeled studies indicated that at 3 h after application an equivalent amount of14C was accumulated in the plant as compared with the rain-free control. The correlation coefficients for fresh weight reductions and14C in the plant were r = 0.53, 0.75, 0.68, 0.74, and 0.70 at rates of 9, 18, 36, 54, and 72 g/ha AC 263,222, respectively.
Eradication of Noxious Visual Aids: Slides and Overheads That Work
Authors: Heap Ian M. , Burrill Larry C. , Dewey Steven A. , Macdonald Gregory E.
Published: March 2018

Weed scientists regularly attend conferences, symposiums, and workshops to communicate with colleagues about their current weed research programs. Communication of research can be hindered by poor visual aids. Computer programs, film recorders, and color printers have greatly increased the ease of visual aid production but have also increased the opportunity to prepare incomprehensible presentations. The size of the text, the amount of information presented, and the contrast between the text color and background color are the most important factors that affect the legibility of visual aids. Text, tables, and graphs should be short, simple, and legible. Computers and film recorders are not essential to produce good visual aids. The greatest assets in the production of visual aids are common sense, familiarity with the production equipment, sufficient preparation time, and critical assessment of the visual aids well in advance of the presentation date.
Response of Triallate-Resistant Wild Oat (Avena fatua) to Alternative Herbicides
Authors: Blackshaw Robert E. , O'Donovan John T. , Sharma M. Paul , Harker K. Neil , Maurice Denise
Published: March 2018

Wild oat populations resistant to triallate have been identified in Alberta. Dose response experiments were conducted in the greenhouse to determine if triallate-resistant wild oat was controlled by other selective wild oat herbicides. Triallate-resistant wild oat populations were effectively controlled by atrazine, ethalfluralin, fenoxaprop-P, flamprop, imazamethabenz, and tralkoxydim. EPTC and cycloate, which are chemically related to triallate, differed in their efficacy on triallate-resistant wild oats. EPTC at the 0.25x field use rate was more efficacious on triallate-resistant than triallate-susceptible wild oat. In contrast, cycloate at the 0.25 to 0.5x field use rate was less efficacious on triallate-resistant than susceptible wild oats. At higher rates, both EPTC and cycloate killed triallate-resistant wild oat populations. Growers have several herbicide choices to selectively control triallate-resistant wild oat in prairie field crops but should plan to rotate herbicides among different chemical families and adopt integrated weed management practices to reduce the risk of these wild oat populations developing resistance to other wild oat herbicides.
Yellow Nutsedge (Cyperus esculentus) Control in Peanut (Arachis hypogaea) as Influenced by Method of Metolachlor Application
Authors: Grichar W. James , Colburn A. Edwin , Baumann Paul A.
Published: March 2018

Field studies conducted from 1989 through 1991 evaluated methods of metolachlor application including POST followed by irrigation for yellow nutsedge control and peanut response. Metolachlor PPI stunted peanut in two of three years while metolachlor applied at emergence, 10, 20, or 30 days after peanut emergence (DAE) caused no peanut injury. Metolachlor 20 DAE provided > 95% yellow nutsedge control. Metolachlor soil-applied and again POST controlled yellow nutsedge at least 70%; however, some peanut stunting was noted. Bentazon plus metolachlor at 2.24 kg ai/ha controlled yellow nutsedge at least 92% when applied 30 DAE. Peanut yields were consistently the highest with metolachlor PRE at 1.40 kg ai/ha followed by a POST application of 1.40 kg ai/ha at 45 DAE.
Weed Control for the Preservation of Biological Diversity
Authors: Randall John M.
Published: March 2018

Invasions by non-native plants threaten the preservation of many plant and animal species and communities throughout North America. These pest species compete with and displace native plants and animals and may substantially alter ecosystem functions (e.g., fire occurrence and frequency, nutrient cycling). Awareness of these threats among wildland managers has greatly increased in the last decade. In a recent poll of National Park superintendents, 61% of 246 respondents indicated non-native plant invasions were moderate or major problems at their parks. Likewise, over 60% of Nature Conservancy stewards nationwide polled in 1992 indicated weeds were among their top 10 management problems, listing nearly 200 problem species. Over 12% indicated weeds were their worst problem. Weed control programs are now in place in wildlands across the continent, employing techniques ranging from manual removal, mechanical methods, prescribed fire, judicious use of herbicides, the release of biological control agents, and encouragement of native competitors. The most successful endeavors follow an adaptive management strategy in which plans based on the goals of the preserve are developed, weeds that interfere with those goals are identified and prioritized, and control measures are selected and implemented where appropriate. Emphasis is placed on preventing new weeds from becoming established and on early detection and elimination of incipient infestations. Managers must focus on the vegetation or community desired in place of the weeds and periodically re-evaluate whether their programs are moving them toward this objective. Control of weeds in wildlands poses unusual problems not ordinarily met in other systems which offer challenging research opportunities for weed scientists and ecologists.
Achieving Conservation Biology Objectives with Fire in the Pacific Northwest
Authors: Agee James K.
Published: March 2018

Fire has been a part of natural ecosystems for many millennia. The species of those ecosystems have evolved through a series of “coarse filters,” one of which is resistance or resilience to disturbance by fire. Plant adaptations to fire include the ability to sprout, seed bank adaptations in the soil or canopy, high dispersal ability for seeds, and thick bark. These adaptations are often to a particular fire regime, or combination of fire frequency, intensity, extent, and season. Fire can be used by managers to achieve species to ecosystem-level conservation biology objectives. Examples using prescribed fire include the grasslands of the Puget Trough of Washington State, maintenance of oak woodlands, and perpetuation of ponderosa pine/mixed-conifer forests.
Cultivation Enhances Weed Control in Soybean (Glycine max) with AC 263,222
Authors: Newsom Larry J. , Shaw David R.
Published: March 2018

Cultivations in conjunction with POST applications of AC 263,222 were evaluated for their effects on sicklepod and pitted morningglory control and soybean yield. Cultivation alone controlled sicklepod and pitted morningglory season-long no more than 30%. In most instances, one cultivation with herbicides improved sicklepod and pitted morningglory control compared with no cultivation, but two cultivations did not further improve control. Two applications of AC 263,222 at 9 or 13 g ai/ha per application with a single cultivation caused the most soybean injury and were no more efficacious than imazaquin applied PRE followed by 9 g/ha AC 263,222. Imazaquin applied PRE followed by AC 263,222 at 18 g/ha plus one or two cultivations were the only treatments that controlled sicklepod and pitted morningglory more than 90% season-long. Cultivation in combination with herbicides increased yields over that of herbicides used alone. Soybean yield was the highest following imazaquin applied PRE followed by AC 263,222 at 9 g/ha plus two cultivations.