bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural features and formation conditions of mud diapirs in the Andaman Sea Basin
Authors: HE WENGANG , ZHOU JIANXUN
Published: March 2018

Data from offshore oil and gas explorations have revealed that mud diapirs occur widely not only at continental margins but also in foreland basins and may have played an important role in the entrapment of oil and gas. Although the structural features and formation mechanism of salt diapirs have been extensively investigated, mud diapirs are still not fully understood, largely due to the difficulty of identifying them from seismic data. In this paper, the structural features and main controlling factors of mud diapirs in the Andaman Sea Basin are investigated based on seismic profiles combined with drilling data and regional tectonic settings. The results show that there are five types of mud diapir in the Andaman Sea Basin: turtleback mud diapir, mud dome, piercing mud diapir, mud volcano and gas chimney-like mud diapir. Turtleback mud diapirs mainly occur in the southern segment of the accretionary wedge of the Andaman Sea Basin, which is far from the Bengal Fan and characterized by low deposition rate and strong compression tectonic setting. Piercing mud diapirs exist mainly in the central segment of the accretionary wedge, which is close to provenances of sediments and characterized by rapid sedimentation rates, large mudstone thickness and transpressional tectonic setting. Mud domes and mud volcanoes mainly occur in the northern segment of the accretionary wedge, which is characterized by rapid sedimentation rates, large mudstone thickness and sedimentary wedge growth tectonic setting. The gas chimney-like mud diapirs only occur in the northern segment of the back-arc depression close to the Sagaing strike-slip fault belt, which is characterized by high deposition rate, large mudstone thickness and high geothermal gradient. These features suggest that thick mudstone deposit, rapid sedimentation rates, large geothermal gradient, strong tectonic stress and gravitational spreading and sliding may have prompted the formation of mud diapirs in the Andaman Sea Basin.
PATIENT AND PUBLIC INVOLVEMENT IN EARLY AWARENESS AND ALERT ACTIVITIES: AN EXAMPLE FROM THE UNITED KINGDOM
Authors: Simpson Sue , Cook Alison , Miles Kathryn
Published: March 2018

Objectives: The aim of this study is to report on the experiences, benefits, and challenges of patient and public involvement and engagement (PPIE) from a publicly funded early awareness and alert (EAA) system in the United Kingdom.

Methods: Using email, telephone, a Web site portal, Twitter and focus groups, patients and the public were involved and engaged in the recognized stages of an EAA system: identification, filtration, prioritization, early assessment, and dissemination.

Results: Approaches for PPIE were successfully integrated into all aspects of the National Institute for Health Research Horizon Scanning Research and Intelligence Centre's EAA system. Input into identification activities was not as beneficial as involvement in prioritization and early assessment. Patients gave useful insight into the Centre's Web site and engaging patients using Twitter has enabled the Centre to disseminate outputs to a wider audience.

Conclusions: EAA systems should consider involving and engaging with patients and the public in identification, prioritization, and assessment of emerging health technologies where practicable. Further research is required to examine the value and impact of PPIE in EAA activities and in the early development of health technologies.
Seasonality of vocal activity of a bird community in an Afrotropical lowland rain forest
Authors: Vokurková Jana , Motombi Francis N. , Ferenc Michal , Hořák David , Sedláček Ondřej
Published: March 2018

Recent observations from the tropics indicate seasonal peaks in breeding and vocal activity of some bird species. However, information about seasonality in vocal activity at the community level is still lacking in the tropics. We examined seasonal variation in the diurnal vocal activity of lowland rain forest birds on Mount Cameroon, using weekly automatic sound recording throughout the whole year and related it to rainfall and temperature. We show that the bird community in lowland rain forest vocalized year-round, but species richness as well as the vocal activity of the community varied greatly during the year. This variation coincided with the seasonality of rainfall. The highest number of species (31.5 on average) sang at the beginning of the driest period, followed by a gradual decrease in singing with increasing rainfall (minimum 14.5 species). This indicates that intensive rainfall indirectly limits the vocal activity of the tropical rain-forest bird community. Temporal turnover of vocalizing species as well as within-day variation in vocal activity was highest during the transition period between dry and rainy seasons. We suggest that this could reflect differing timing in the breeding activity of particular feeding guilds to follow seasonal peaks of their diets.
Effect of Corn (Zea mays) Genotypes Which Vary in Maturity Length onStriga hermonthicaParasitism
Authors: Ransom Joel K. , Odhiambo George D.
Published: March 2018

Corn (maize) genotypes which varied in days to maturity were evaluated for level ofStriga hermonthicaparasitism in western Kenya during three seasons. Fifteen genotypes, with a wide range in days to maturity, were grown in fields heavily infested withS. hermonthica.Early and late-seasonStriganumbers and corn grain yield were used to evaluateStrigaparasitism. There was considerable variation in the timing and amount ofStrigaattachment among seasons. Days to silking and late-seasonStriganumbers were correlated (P ≤ 0.05) in all experiments although only weakly in one of the experiments. Grain yield was negatively correlated with days to silking in two of three experiments as were yield and early seasonStriganumbers. Although earlier-flowering genotypes consistently supported lessStriga, they did not always yield more than the later-maturing genotypes due to confounding effects of yield potential and adaptation. There was considerable variation inStrigaparasitism among genotypes within maturity groups, and the relative response of genotypes varied between seasons. These data suggest that in some seasons early maturing genotypes have potential to reduceStrigaattack in heavily infested areas and yield more than later-maturing genotypes.
Effect of Postplant Tillage and Crop Density on Broadleaf Weed Control in Dry Pea (Pisum sativum) and Lentil (Lens culinaris)
Authors: Boerboom Chris M. , Young Frank L.
Published: March 2018

Increased crop densities and postplant tillage were evaluated as nonchemical methods to supplement metribuzin for improved broadleaf weed control in dry pea and lentil. The effects of 50, 100, and 150% of recommended 220 kg/ha pea and 67 kg/ha lentil seeding rates and two dates of rotary hoeing and harrowing on pea, lentil, and broadleaf weeds were studied with and without metribuzin for two years. Under favorable growing conditions, crop competition gave 72 and 99% weed control in pea and 33 and 70% weed control in lentil with the 50 and 150% seeding rates. Under less favorable conditions, control was 21 to 39% with the low and high pea and lentil seeding rates. At recommended seeding rates, metribuzin gave greater than 90% control in either crop or year. Postplant tillage 12 to 27 d after planting slightly reduced crop densities in three tillage treatments in one year, but not the second. Postplant tillage did not affect crop yield or improve weed control. In all studies, pea was similar to or more competitive than lentil in suppressing broadleaf weeds. Because neither non-chemical practice significantly improves weed control, changes are not recommended for weed management in pea and lentil.
Effects of Band Widths on Atrazine, Metribuzin, and Metolachlor Runoff
Authors: Gaynor John D. , Van Wesenbeeck Ian J.
Published: March 2018

The potential reduction in surface runoff loss of band-applied herbicides was studied in a rainfall simulation. Concentration and loss of atrazine, metribuzin, and metolachlor applied in a band 25, 50, or 75 cm wide on 1-m2 plots graded to < 0.5% slope were compared with that from a broadcast preemergence application. Herbicide concentration in runoff decreased with time after initiation of runoff and as application band width decreased. Band width reduced herbicide concentration in runoff to a greater extent than time after initiation of runoff. The 50-cm band treatment reduced atrazine and metribuzin loss 69 and 71%, respectively, from the broadcast treatment. Forty-nine percent less metolachlor was lost from the 50-cm band than from the broadcast treatment. Herbicide concentration or loss in surface runoff did not differ between the 50- and 25-cm band width treatments. Herbicide lost in runoff ranged from 4 to 7% of application with the smaller loss associated with narrower band widths. The greater reduction in atrazine and metribuzin loss in surface runoff than that associated with the reduction in input alone may be attributed to leaching or adsorption of herbicide by soil in the nonsprayed strip as runoff flowed from the treated to the nontreated areas. Band application of herbicides may provide an effective, consistent means to reduce herbicide loss in surface runoff.
Effect of Paclobutrazol and Flurprimidol on Suppression ofPoa annuaspp.reptansin Creeping Bentgrass (Agrostis stolonifera) Greens
Authors: Johnson B. Jack , Murphy Tim R.
Published: March 2018

Plant growth regulators paclobutrazol and flurprimidol were evaluated for suppression ofPoa annuaspp.reptans, a perennial biotype of annual bluegrass, in a creeping bentgrass green. Paclobutrazol at 0.6 kg ai/ha applied on Mar. 15, followed by 0.3 kg/ha on Apr. 29, 0.6 kg/ha on Oct. 1, and 0.3 kg/ha on Nov. 12 for each of 2 yr suppressedP. annuaspp.reptans28% approximately 4 mo after the final treatment. When paclobutrazol was applied at 0.3 kg/ha in each of four applications during the same period, suppression was similar to that with the higher rate 1 and 2 mo after final treatment but declined to 7% by 4 mo. Suppression ofP. annuaspp.reptansfrom flurprimidol applied four times during each of 2 yr was 22 to 27% 1 mo after final treatment but no suppression was noted 2 mo after the final treatment. Maximum creeping bentgrass injury was less than 20% when either paclobutrazol or flurprimidol was applied in the spring. However, creeping bentgrass injury was approximately 30% in the fall when either chemical was applied in the spring and repeated in October at 0.6 kg/ha.
Optimal Glyphosate Application Time for Control of Foxtail Barley (Hordeum jubatum)
Authors: Conn Jeffery S. , Deck Richard E.
Published: March 2018

Optimal time of application of the isopropylamine salt of glyphosate for long-term control of foxtail barley was studied near Delta Junction, AK in 1992 and 1993. Applications of either 0.6 or 1.1 kg/ha of glyphosate with 2.2 kg/ha of ammonium sulfate and 0.5% (v/v) nonionic surfactant were made to different foxtail barley plots at approximately 2-wk intervals from May to September. Control was rated in July of the year following application. The 0.6 kg/ha rate produced ≤ 60% control on all application dates. At 1.1 kg/ha, foxtail barley control was best from applications made between early August and mid-September. May and mid-June applications provided up to 80% control in 1993 but ≤ 50% control in 1992. For both rates, applications made from late June through July, during foxtail barley flowering and seed fill, consistently provided little control (< 50%).
Effect of Soybean (Glycine max)Cultivar, Tillage, and Rye (Secale cereale)Mulch on Sicklepod (Senna obtusifolia)
Authors: Shilling Donn G. , Brecke Barry J. , Hiebsch Clifton , MacDonald Gregory
Published: March 2018

Field studies were conducted to determine the effect of soybean cultivar, tillage, and rye mulch on sicklepod growth. Early-season sicklepod height was not affected by tillage or mulch. Sicklepod was tallest when grown with ‘Centennial’ or ‘Biloxi,’ the tallest cultivars, and shortest when grown with a dwarf isoline of ‘Tracy M,’ the shortest cultivar. Soybean competition reduced early-season weed density by 30 to 50%, depending on the cultivar. Centennial and dwarf Tracy M caused a 30% reduction in early-season sicklepod biomass while ‘Sharkey’ and Biloxi reduced sicklepod growth by 40%. By late-season, sicklepod biomass reduction ranged from 18% (Tracy M) to 55% (Biloxi) and was directly related to soybean cultivar height. Mulch or no-tillage independently reduced sicklepod biomass.
Effects of Grain Sorghum (Sorghum bicolor)Herbicides on Charcoal Rot Fungus
Authors: Russin John S. , Carter Carol H. , Griffin James L.
Published: March 2018

Laboratory and greenhouse studies examined effects of atrazine, alachlor, and metolachlor on growth and colonization of grain sorghum roots byMacrophomina phaseolina, causal fungus for charcoal rot disease. In laboratory studies, all three herbicides reduced fungal colony diameter and increased production of microsclerotia. Alachlor and metolachlor reduced germination of fungal microsclerotia. Atrazine did not affect microsclerotia germination, but lessened the effects of alachlor and metolachlor on germination when applied in combination. In greenhouse studies, atrazine reduced numbers ofM. phaseolinamicrosclerotia recovered from soil after 8 wk, and this resulted in reduced colonization of roots by this fungus at harvest. Colonization of grain sorghum roots byM. phaseolinawas not affected by alachlor or metolachlor. Grain sorghum growth was reduced by atrazine at all intervals and by alachlor and metolachlor at harvest, despite use of seed safened with cyometrinil.
Standard Operating Procedures (SOPs) for Research in Weed Science
Authors: Donald William W. , Schwartz Paul H.
Published: March 2018

Standard operating procedures (SOPs) were developed for repetitive field research tasks to help ensure that instructions were complete and to provide consistency and continuity in the senior author's field research program. SOPs are explicit step-by-step instructions for carrying out experimental tasks that are components of experimental plans. SOPs are not the same as protocols for unique, new experimental plans. However, protocols may incorporate sequences of SOPs, if desired. SOPs are most useful for new workers and when research tasks need to be repeated infrequently in time (e.g., once every 6 mo or less per year). SOPs may help researchers enhance data accuracy, precision, and reproducibility as part of their own statistical quality control procedures. The authors' field-tested SOPs are available on diskette for critical review, modification, and use by interested weed scientists.
Control of Persian Darnel (Lolium persicum) and Other Grasses with Clethodim
Authors: Hunter James H.
Published: March 2018

The response of Persian darnel, green foxtail, wild oat, and volunteer cereals to clethodim applied at two growth stages, and the effect of these treatments on flax yield and quality were determined in a series of field experiments in which each weed species was evaluated separately. Clethodim applied at 45 g/ha provided excellent control of Persian darnel, green foxtail, wild oat, and volunteer wheat and barley. Sethoxydim applied at 150 g/ha provided excellent control of Persian darnel, green foxtail, wild oat, and volunteer barley. Rax was tolerant at five times the recommended rate of application and was unaffected by plant growth stage at time of application. When applied at an early (2- to 3-leaf) stage, control of Persian darnel, green foxtail, wild oat, and volunteer wheat and barley was excellent at 20 g/ha. Except for Persian darnel, weed control as determined by reduction in plant dry weight, was negatively affected by growth stage at time of application. Although visible control and reduction in plant dry weight were somewhat less when clethodim was applied at the 4-to 5-leaf stage, control of each weed species was acceptable. When weight of water in plant tissue (fresh weight – dry weight) was used as a measure of living plant tissue, wild oat and volunteer barley control were unaffected by growth stage at time of application.
Detection of Yellow Hawkweed (Hieracium pratense) with High Resolution Multispectral Digital Imagery
Authors: Carson Hubert W. , Lass Lawrence W. , Callihan Robert H.
Published: March 2018

Yellow hawkweed infests permanent upland pastures and forest meadows in northern Idaho. Conventional surveys to determine infestations of this weed are not practical. A charge coupled device with spectral filters mounted in an airplane was used to obtain digital images (1 m resolution) of flowering yellow hawkweed. Supervised classification of the digital images predicted more area infested by yellow hawkweed than did unsupervised classification. Where yellow hawkweed was the dominant ground cover species, infestations were detectable with high accuracy from digital images. Moderate yellow hawkweed infestation detection was unreliable, and areas having less than 20% yellow hawkweed cover were not detected.
Tomato (Lycopersicon esculentum) Cultivar and Weed Sensitivity to DPX-E9636
Authors: Bewick Thomas A. , Smith Kenneth , Stall William M. , Olson Steven M.
Published: March 2018

Sensitivity of 49 tomato cultivars and four weeds to DPX-E9636 was determined in greenhouse experiments. Cultivar tolerance varied from completely tolerant to intolerant. The most efficacious application method in greenhouse experiments was early POST for the weeds tested (yellow nutsedge, prostrate eclipta, and paraquat-resistant and -sensitive American black nightshade). Paraquat-resistant American black nightshade was 123 times more sensitive to DPX-E9636 than the paraquat-sensitive biotype. Under field conditions and at 0, 36, or 72 g ai/ha applied one week after transplanting, tomato cultivars showed no response to DPX-E9636 in visual vigor ratings 3 wk treatment, or in shoot fresh or dry weight 4 wk after treatment.
Cross-Resistance of a Large Crabgrass (Digitaria sanguinalis) Accession to Aryloxyphenoxypropionate and Cyclohexanedione Herbicides
Authors: Wierholt Ronald J. , Stoltenberg David E.
Published: March 2018

A large crabgrass population (PW2) that demonstrated resistance to fluazifop-P and sethoxydim was identified in Wisconsin during 1992. Dose-response experiments were conducted in the greenhouse to determine the level of resistance of a PW2 large crabgrass accession to aryloxyphenoxypropionate (APP), cyclohexanedione (CHD), and other herbicide chemistries relative to a large crabgrass accession (A310) which was susceptible to APP and CHD herbicides. Based on shoot dry biomass reduction, the PW2 accession was 337- and 59-fold resistant to sethoxydim and fluazifop-P, respectively, relative to the A310 accession. Resistance of the PW2 accession to fenoxaprop, haloxyfop, quizalofop, and diclofop ranged from 18- to 29-fold. The PW2 accession was only 7-fold resistant to clethodim. Both large crabgrass accessions were susceptible to imazethapyr and linuron. These results suggest that APP and CHD herbicides will be ineffective for the management of the PW2 accession. An integrated approach including cultural, mechanical, and alternative chemical methods, should be implemented for the management of the PW2 accession and to prevent additional resistance problems.
HOE 075032 for Wild Mustard (Sinapis arvensis) Control in Canola (Brassica rapa)
Authors: Kirkland Kenneth J.
Published: March 2018

The tolerance of canola and wild mustard to postemergence HOE 075032 was investigated in greenhouse and field studies. In the greenhouse, the tolerance of canola to HOE 075032 applied at the 2 Ho 3-leaf stage was approximately twice the tolerance of wild mustard. In the field, HOE 075032 applied at 5 and 10 g ai/ha at the 2 to 3-leaf stage reduced wild mustard plant density and fresh weight by over 95%. Wild mustard contamination in canola seed was reduced from 45 to less than 1%. Application of HOE 075032 at 5 g/ha significantly increased canola yield and fresh weight in each year. Canola yield increases of 25, 139, and 86% were observed for the 5 g/ha treatment in 1991, 1992, and 1993, respectively. HOE 075032 could provide a postemergent alternative to the existing herbicide for wild mustard control in canola.
Sweet Potato (Ipomoea batatas) Clones Differ in Response to Ethyl-Metribuzin
Authors: Motsenbocker Carl E. , Monaco Thomas J.
Published: March 2018

Six commercial sweet potato clones were evaluated in field and greenhouse studies for the ethylthio analog of metribuzin (ethyl-metribuzin) tolerance. ‘Southern Delite’ was most tolerant in field studies and ‘Cordner’ the most tolerant in the greenhouse. ‘White Delite’ was the most susceptible clone in the field and greenhouse. Considering the rates used in this study, all the sweet potato clones generally were tolerant to ethyl-metribuzin. When averaged over all clones, sweet potato injury increased as the ethyl-metribuzin rate increased from 1.6 to 3.2 kg/ha but injury decreased as the season progressed and was minimal in late season. Ethyl-metribuzin did not reduce marketable yields at Clayton, NC. At Clinton, NC, ethiozin PRE, POST, or PRE followed by POST at 3.2 kg/ha or PRE at 1.6 kg/ha reduced yield.
Soybean (Glycine max) Response to AC 263,222 and Chlorimuron as Influenced by Soil Moisture
Authors: Newsom Larry J. , Shaw David R.
Published: March 2018

Field experiments conducted in 1992 and 1993 evaluated differential response of 20 soybean cultivars to POST application of AC 263,222 or chlorimuron, as influenced by soil moisture. Natural rainfall was supplemented with overhead sprinkler irrigation to achieve three moisture regimes: excessive (12.5 cm/wk), optimum (5 cm/wk), and low (non-irrigated). Chlorimuron and AC 263,222 injured soybean. Excessive moisture did not increase soybean injury with chlorimuron for any of the cultivars tested compared to optimum moisture; however, 17 of 20 cultivars were injured more by AC 263,222 in combination with excessive moisture than optimum moisture. AC 263,222 reduced the height of five cultivars. Photosynthetic rate of several cultivars was reduced by both AC 263,222 and chlorimuron. Neither herbicide affected the number of nodes per main stem or seed weight; however, pod numbers were reduced for several cultivars with both herbicides. In the low moisture regime, AC 263,222 delayed the maturity of 18 of 20 cultivars with ‘Hutcheson’ maturity delayed 7.1 d. Excessive moisture when combined with AC 263,222 reduced yields for 12 cultivars, compared to five cultivars with chlorimuron. Under optimum moisture conditions, AC 263,222 reduced the yield of 10 cultivars, whereas chlorimuron reduced the yield of 9 cultivars. Low moisture stress only resulted in a yield reduction with 3 cultivars treated with AC 263,222.
Growth Characteristics of Selected Dinitroaniline-Resistant and -Susceptible Goosegrass (Eleusine indica) Population
Authors: Harris James R. , Gossett Billy J. , Toler Joe E.
Published: March 2018

Growth and development of selected dinitroaniline-resistant (DR) and -susceptible (DS) goosegrass populations were compared in field studies in replacement series, in association with cotton, and under noncompetitive conditions. The DR ‘Florence’ (FR) and DS ‘Orangeburg’ (OS) populations were similar in competitiveness as indicated by relative yields (RY) and relative crowding coefficients (RCC) for vegetative and reproductive biomass production in a replacement series. Relative growth of the FR and DS ‘Anderson’ (AS) populations in replacement series was similar when vegetative biomass was considered, but reproductive biomass of the AS population declined as proportion of FR population increased. RCC values also indicated that the FR population interfered with reproductive development of the AS population. In field studies, the FR population produced greater vegetative biomass than either DS population, while similar reproductive biomass occurred for the FR and OS populations. Inflorescence dry weights were greater for the FR than the AS population under noncompetitive conditions and in cotton, but were greater for the AS population in replacement series studies. The competitiveness of DR and DS goosegrass biotypes appears to be more related to growth characteristics of individual populations than to response to dinitroaniline herbicides.
The Effect of Nicosulfuron Tank-Mixes and Time of Application on Sunrunner Peanut (Arachis hypogaea)
Authors: Littlefield Terry A. , Colvin Daniel L. , Brecke Barry J. , McCarty Lambert B.
Published: March 2018

Field experiments conducted in Marianna, Trenton, and Archer, FL in 1990 and 1991 investigated the effect of time of application of nicosulfuron and nicosulfuron mixtures on ‘Sunrunner’ peanut. Nicosulfuron was applied alone at 36 g ai/ha and in mixture with acifluorfen, bentazon, chlorimuron, chlorothalonil, fluazifop-P, imazethapyr, lactofen, or pyridate at 5, 7, or 9 weeks after planting (WAP). Applying nicosulfuron with chlorimuron, pyridate, or imazethapyr increased visible peanut injury and reduced yields more than nicosulfuron alone. Conversely, nicosulfuron applied with acifluorfen or lactofen was less injurious than nicosulfuron applied alone. Bentazon, chlorothalonil, and fluazifop-P generally did not influence phytotoxicity from nicosulfuron. Peanut tolerance to nicosulfuron increased with age.
Design, Construction, and Operation of an Agricultural Pesticide Facility
Authors: Burnside Orvin C. , Wass Brian C. , Rees Kent A. , Warnke Thomas W.
Published: March 2018

This paper describes the planning, designing, constructing, and initial operating phases of a state-of-the-art agricultural pesticide facility (APF). The APF on the University of Minnesota, St. Paul Campus is located within a major metropolitan area, causing environmental and human safety to be priority considerations. The building site was located adjacent to a greenhouse complex and field plots to provide access for all users of pesticides on the St. Paul Campus for storing, measuring, packaging for off campus use, applying, and disposing of pesticides. This central facility eliminated the need for about 25 generally inadequate locations on campus where pesticides were previously stored and handled. Changing state and federal pesticide regulations and in-house operating requirements may require future modification and retrofitting of the APF. However, the APF is a valuable research and education addition to the St. Paul Campus, and it has provided greater safety for personnel, students, visitors, the community, and the environment.
Constraints in the Development of Bioherbicides
Authors: Auld Bruce A. , Morin Louise
Published: March 2018

Bioherbicides are biological control agents applied in similar ways to chemical herbicides to control weeds. The active ingredient in a bioherbicide is a living microorganism and it is applied in inundative doses of propagules. Most commonly the microorganism used is a fungus and its propagules are spores or fragments of mycelium; in this case the bioherbicide is also referred to as a mycoherbicide.

Commercial bioherbicides first appeared on the market in the USA in the early 1980s with the release of the product DeVine® in 1981 and in the next year, the release of the product Collego®. In spite of considerable public research effort and many promising candidate organisms, only one other bioherbicide product, BioMal®, has been registered (in Canada) since then. Furthermore none of these products are currently commercially available for a variety of reasons that will be discussed below.
Methods of Measuring the Impact of the XA17 Gene on Imazethapyr Injury in Corn (Zea mays)
Authors: Currie Randall S. , Regehr David L.
Published: March 2018

Imazethapyr dose response curves were developed under laboratory and field conditions with the imazethapyr-resistant and -susceptible corn hybrids Pioneer 3180IR, IR denoting a hybrid homozygous for the XA17 gene conferring resistance to imazethapyr, and normal Pioneer 3180, respectively, and their F1progeny to establish methods of measuring the presence of the XA17 gene and quantifying its impact. At two field locations, absorption of photosynthetically active radiation was a sensitive index of corn injury caused by imazethapyr. Imazethapyr, at 35 g/ha (one half the labeled rate), reduced absorption of photosynthetically active radiation in Pioneer 3180 by 8.3% at 1 wk after treatment. Plant height also was a sensitive index of injury. The minimum rate at which imazethapyr injury was detected in the Pioneer 3180IR/Pioneer 3180 F1hybrid differed with location. Pioneer 3180IR was not injured by 280 g/ha of imazethapyr. The Pioneer 3180IR/3180 F1hybrid was injured slightly by imazethapyr at 140 g/ha, but recovered within 5 wk after treatment, and grain yield was not reduced by 280 g/ha of imazethapyr. A seedling assay reliably detected differences between progeny of Pioneer 3180IR and Pioneer 3180IR/3180 F1.
Nicosulfuron and Primisulfuron Eradicate Rhizome Johnsongrass (Sorghum halepense) in Corn (Zea mays) in Three Years
Authors: Tweedy Michael J. , Kapusta George
Published: March 2018

Field studies were conducted at Carbondale, IL from 1992 to 1994 to evaluate rhizome johnsongrass control in field corn with nicosulfuron and primisulfuron applied POST without or with EPTC applied PPL EPTC applied PPI at 4480 and 6720 g ai/ha plus dichlormid controlled johnsongrass 38 and 60% in 1992 and 29 and 41% in 1993, respectively, and 0% in 1994. EPTC did not decrease johnsongrass rhizome weight, length, or number of nodes in any year. Nicosulfuron at 35 g/ha and primisulfuron at 40 g/ha applied to 38-cm tall plants controlled 94 to 100% and 85 to 100%, respectively, from 1992 to 1994. Plots treated for three consecutive seasons with nicosulfuron or primisulfuron did not have any rhizomes. Corn yield was more than double in nicosulfuron and primisulfuron plots compared with control plots.
Effect of Tillage Level and Herbicides on Weed Control and Yield of Asparagus (Asparagus officinalis) in the Pacific Northwest
Authors: Boydston Rick A.
Published: March 2018

Studies were conducted to determine the effects of tillage level on weed control and yield of asparagus grown on a sandy loam soil under sprinkler irrigation. Without herbicides, horseweed and kochia populations increased in no-till asparagus production over a 3-yr period, compared to asparagus that was rototilled either once in the spring or once in the spring and again at layby. Without herbicides, hairy nightshade populations increased most when asparagus was rototilled both in the spring and at layby. Volunteer asparagus was controlled best when herbicides and tillage were combined in the spring and again at layby. Common groundsel was controlled without herbicides by rototilling both in the spring and at layby. Diuron at 1.4 kg ai/ha plus prodiamine at 1.4 kg/ha or metribuzin at 0.9 kg/ha plus norflurazon at 2 kg/ha controlled all weeds under all three tillage levels when split-applied in the spring and at layby. Tillage level had no effect on total asparagus spear number or weight if tillage was performed in mid March before asparagus emergence.
Comparisons Between Resistance Management Strategies for Insects and Weeds
Authors: Gould Fred
Published: March 2018

Problems with insecticide resistance have long plagued the field of economic entomology. Genetic, biochemical, and ecological information on insects has been used to develop strategies to slow the rate of insecticide resistance evolution. Documented cases of herbicide resistance have increased dramatically over the past 10 yr. This paper compares some aspects of insect and weed biology that can be used in determining whether or not resistance management strategies developed for insects are likely to be useful in combating herbicide resistance. Differences between insects and weeds in terms of genetic architecture, mating systems, and population structure lead to differences in the expected efficacy of some resistance management strategies. Because of the localized population structure of some weeds, it may be easier to get farmers to participate in herbicide resistance management programs and avoid a “tragedy of the commons.” A review of the herbicide resistance literature reveals a number of areas of basic research on ecology and genetics of weeds that could help in designing more appropriate resistance management programs.
Fungicide Resistance—Lessons for Herbicide Resistance Management?
Authors: Peever Tobin L. , Milgroom Michael G.
Published: March 2018

Resistance to agricultural fungicides has increaséd dramatically in the past twenty years, following the introduction of systemic fungicides. Disease control failures associated with fungicide resistance have occurred with many classes of fungicides and in many genera of plant-pathogenic fungi. In some cases, resistance evolved extremely rapidly making the chemicals ineffective for disease control only a few years after they were introduced.

The rapid development of resistance to systemic fungicides has led to efforts to develop strategies to avoid or delay the evolution of fungicide resistance in plant pathogen populations. Despite a widespread interest in managing fungicide resistance, very few experimental studies have been performed to elucidate the important factors controlling resistance development. Most fungicide resistance studies have consisted of anecdotal field observations which have rarely been followed up with experimentation. In order to understand what factors affect the evolution of resistance, and to use this information to design effective resistance management strategies, more experimental studies are required.
Control of Legume Cover Crops in No-Till Corn (Zea mays) and Cotton (Gossypium hirsutum)
Authors: White Randall H. , Worsham A. Douglas
Published: March 2018

Eight herbicide treatments per crop were evaluated for hairy vetch and crimson clover cover-crop control in no-till corn and cotton at two locations in North Carolina. Paraquat alone or combined with dicamba, 2,4-D, or cyanazine, and cyanazine alone, controlled clover the best in both crops. All herbicide treatments, except glyphosate alone, controlled at least 89% of hairy vetch in corn. However, only 2,4-D and cyanazine alone or combined with glyphosate controlled greater than 89% of hairy vetch in cotton. Except for poor control of hairy vetch and crimson clover by glyphosate alone, reduced legume control did not consistently decrease corn or cotton yield. Weed control was reduced in crimson clover treated with glyphosate alone, but control was similar among the remaining herbicide treatments. Effectiveness of legume control did not influence the N concentration of corn or cotton. Corn stand, height, and yield were greater in hairy vetch than in crimson clover. Seed cotton yield did not differ between vetch and clover.
Effects of (NH4)2SO4and BCH 81508 S on Efficacy of Sethoxydim
Authors: York Alan C. , Jordan David L. , Wilcut John W.
Published: March 2018

Field experiments were conducted to determine effects of adding 2.8 kg/ha (NH4)2SO4and/or substituting BCH 81508 S for crop oil with sethoxydim applied to large crabgrass, corn, johnsongrass, and common bermudagrass. Adding (NH4)2SO4did not affect control of johnsongrass or common bermudagrass but did increase control of large crabgrass and corn by 6 and 15%, respectively. Cora control was enhanced more by (NH4)2SO4at lower sethoxydim rates. Substituting BCH 81508 S for crop oil increased seedling johnsongrass, large crabgrass, common bermudagrass, rhizome johnsongrass, and corn control by 7, 9, 9, 10, and 15%, respectively. A sethoxydim rate by spray adjuvant interaction was observed with seedling johnsongrass, common bermudagrass, and corn where response to BCH 81508 S decreased as sethoxydim rates increased. The effects of substituting BCH 81508 S for crop oil and adding (NH4)2SO4were independent.
Herbicide Systems for Johnsongrass (Sorghum halepense) Control in Soybeans (Glycine max)
Authors: Winton-Daniels Kim , Frans Robert , McClelland Marilyn
Published: March 2018

Fenoxaprop, fluazifop-P, haloxyfop, quizalofop, and sethoxydim applied postemergence reduced johnsongrass populations in soybeans over a 3-yr period. The selective postemergence herbicides were more effective as split applications than as single, high-rate applications for controlling heavy infestations of johnsongrass. Fluchloralin applied preplant incorporated decreased the number of postemergence applications required to maintain johnsongrass control above 80%, although control depended primarily upon the selective, postemergence herbicides. Glyphosate applied by ropewick reduced johnsongrass populations more when used in conjunction with fluchloralin than when used alone.
Agronomic Practices Influencing Triazine-Resistant Weed Distribution in Ontario
Authors: Stephenson Gerald R. , Dykstra Marilyn D. , McLaren R. Douglas , Hamill Allan S.
Published: March 2018

Triazine-resistant (TR) biotypes of weeds normally susceptible (S) to triazine herbicides first were documented in Ontario in 1974. By 1988, at least nine weed species had TR biotypes, and at least 50% of the corn-producing areas were infested. Corn has been grown the longest in the southwestern Ontario, but TR weeds are only a minor problem there. Predominant agronomic practices in the southwest include crop rotation, atrazine use on 60% of corn land, use of other postemergence herbicides, interrow cultivation, little silage corn, and little manure returned to the land. Corn, particularly grain corn, is new as a large hectareage crop in eastern Ontario. However, more than 75% of corn land in that area is infested with two or more TR weed species. Predominant agronomic practices in the east include continuous corn, nearly all fields are atrazine treated, use of postemergence herbicides is not common, cultivation is rare, 25% of the corn is for silage, and manure from corn silage is returned to all cultivated land. Adequate herbicide programs exist to control TR weeds in corn and other crops. However, the spread from field to field and from farm to farm is often rapid, particularly in eastern Ontario.
Interference of Three Annual Grasses with Grain Sorghum (Sorghum bicolor)
Authors: Smith Brenda S. , Murray Don S. , Green J. D. , Wanyahaya Wan M. , Weeks David L.
Published: March 2018

Barnyardgrass, large crabgrass, and Texas panicum were evaluated in field experiments over 3 yr to measure their duration of interference and density on grain sorghum yield. When grain yield data were converted to a percentage of the weed-free control, linear regression predicted a 3.6% yield loss for each week of weed interference regardless of year or grass species. Grain sorghum grown in a narrow (61-cm) row spacing was affected little by full-season interference; however, in wide (91-cm) rows, interference increased as grass density increased. Data from the wide-row spacing were described by linear regression following conversion of grain yield to percentages and weed density to log10. A separate nonlinear model also was derived which could predict the effect of weed density on grain sorghum yield.
Control of Roughstalk Bluegrass (Poa trivialis) with Fenoxaprop in Perennial Ryegrass (Lolium perenne) Grown for Seed
Authors: Mueller-Warrant George W.
Published: March 2018

Fenoxaprop applied between late winter and mid-spring selectively controlled roughstalk bluegrass in perennial ryegrass grown for seed in Oregon. Fenoxaprop applied after the arrival of warmer weather in late March had enhanced effectiveness against roughstalk bluegrass compared to earlier application. However, additional delay into April increased damage to perennial ryegrass. Optimum application date coincided with a 15- to 18-cm perennial ryegrass canopy height. Mixed stands of seedling and established roughstalk bluegrass were more consistently controlled by 0.28 kg ai/ha fenoxaprop than by lower rates.
Economic Returns from Cheat (Bromus secalinus) Control in Winter Wheat (Triticum aestivum)
Authors: Ferreira Kenneth L. , Peeper Thomas F. , Epplin Francis M.
Published: March 2018

Field experiments were conducted to determine the influence of winter wheat seeding date and forage removal on the efficacy of cheat control herbicides, forage and grain yields, and net returns to land, overhead, risk, and management for the various cheat control strategies. Economic analysis showed that net returns were higher when wheat was seeded during the traditional seeding period (October) than when either seeded early (September) for increased forage production or delayed (November) for cultural cheat control. Some herbicides were economically beneficial at two of three locations where the initial cheat population exceeded 170 plants/m2.
Invert Emulsions: Carrier and Water Source for the Mycoherbicide,Alternaria cassiae
Authors: Daigle D. J. , Connick W. J. , Quimby Paul C. , Evans Janice , Trask-Morrell Brenda , Fulgham F. E.
Published: March 2018

The weed sicklepod, a problem in the cultivation of soybean, cotton, and peanut, can be controlled by the mycoherbicide,Alternaria cassiae.However, the presence of water (dew) for an extended period is required by the fungal spores to germinate and infect the target weed. Preliminary tests with invert (water-in-oil) emulsions containing paraffin wax, paraffin oil, lecithin, and water indicated that about 10% (w/w) water, maintained over an 18-h period, was necessary under laboratory conditions for significant germination of the fungus. The ability to maintain that amount of water in the invert emulsion depended upon spray deposit size, adjuvants, and oil phase: water ratio. Paraffin wax was an effective adjuvant for reducing water evaporation and increasing sicklepod mortality in the greenhouse.
Dodder (Cuscutaspp.) Control with Dinitroaniline Herbicides in Alfalfa (Medicago sativa)
Authors: Dawson Jean H.
Published: March 2018

For effective full-season control of dodder in alfalfa produced for seed, herbicides applied to soil in late winter or early spring should remain active through June. Pendimethalin or prodiamine at 2.2 kg ai ha-1applied in mid March controlled 97 to 100% of dodder through May and 92 to 100% through June. At 3.4 kg ha-1, both controlled 96 to 100% of dodder through June each year, and control of 95 or 96% persisted through July in 1 of 3 yr. In the greenhouse, trifluralin was only about 1/8 as active against dodder as pendimethalin and prodiamine. In the field, trifluralin at 2.2 kg ai ha-1controlled dodder satisfactorily through May in 3 of 4 yr and through June in 1 of 4 yr. At 4.5 kg ha-1, trifluralin controlled 99% of dodder through May in each of 3 yr; control was satisfactory through June in 2 of 3 yr. Oryzalin was less effective than the other three dinitroaniline herbicides. A standard herbicide, chlorpropham at 6.7 kg ai ha-1, controlled 97 to 100% of dodder through May, but control usually did not persist through June. Another standard herbicide, DCPA at 11.2 kg ai ha-1, controlled 97 or 98% of dodder through June in 2 of 3 yr. Pendimethalin and prodiamine at 3.4 and 6.7 kg ai ha-1did not affect the yield or quality of seed produced by established alfalfa. Heavy sprinkler irrigation (15 cm of water) after application did not diminish dodder control from pendimethalin or prodiamine.
Growth and Development of Wild-Proso Millet (Panicum miliaceum) Biotypes
Authors: Eberlein Charlotte V. , Lurvey Edith L. , Miller Timothy L. , Michael Janis L.
Published: March 2018

Growth and development of three wild-proso millet biotypes (Cambridge, LeSueur, and Morris) and one cultivated proso millet (‘Crown’) were compared under noncompetitive conditions in field studies. LeSueur and Cambridge were taller than Crown and Morris at maturity. All wild types had greater leaf area and dry weight at maturity than Crown. Crown headed earlier than the wild types, and among the wild types, Cambridge was slowest to mature. Seed production was 1.4 to 2 times greater for wild than cultivated proso millet, and averaged 48 000, 69 000, 83 000, and 94 000 seeds/plant for Crown, Cambridge, LeSueur, and Morris, respectively. Mean seed weight was 4.0 and 3.8 mg/seed for LeSueur and Morris, respectively, and 5.8 and 5.9 mg/seed for Crown and Cambridge, respectively. LeSueur and Morris seed shattered readily, but Cambridge seed shattered relatively little. Seed dormancy was greater in LeSueur and Morris than in Cambridge. Based on reproductive potential, shattering, and dormancy characteristics, LeSueur and Morris appeared to have more weedy characteristics than Cambridge.
Cogongrass (Imperata cylindrical) Distribution on Florida Highway Rights-of-Way
Authors: Willard Tommy R. , Hall David W. , Shilling Donn G. , Lewis James A. , Currey Wayne L.
Published: March 2018

A survey of Florida highway rights-of-way was conducted during 1984–85 to determine the occurrence and severity of cogongrass infestation. Florida Department of Transportation district maintenance engineers surveyed 8,200 km of limited-access and other major highways (22% of highway system). Cogongrass was distributed widely from the north central region southward through the central Florida ridge north of Lake Okeechobee. Highest frequencies were in counties where cogongrass was used for forage and soil stabilization during the 1950s. The large, widely scattered cogongrass infestations probably were established during extensive roadway construction and routine maintenance which used rhizome-contaminated fill soil.
Control of Annual Goldeneye (Viguiera annua) on Rangeland
Authors: Williams M. Coburn
Published: March 2018

Foliar sprays of 2,4-D, dicamba, and triclopyr were applied to vegetative annual goldeneye at 0.56, 1.1, and 2.2 kg ai ha-1. Mortality was 47% and 64% after treatment with triclopyr and 2,4-D at 2.2 kg ha-1, respectively. Mortality was less than 30% at lower rates. Mortality was 54%, 93%, and 100% after treatment with dicamba at 0.56, 1.1, and 2.2 kg ha-1, respectively. Foliar cover of tobosagrass increased 119% and 92% on plots treated with dicamba at 1.1 and 2.2 kg ha-1, respectively. Herbicide treatment did not affect nitrate concentration (0.03% to 0.05%) in treated plants.
Weed Control in No-tillage and Conventional Corn (Zea mays) with ICIA-0051 and SC-0774
Authors: Wilson John S. , Foy Chester L.
Published: March 2018

Field studies were conducted over a four-year period to determine the weed control efficacy of ICIA-0051 and SC-0774 in no-tillage and conventional corn. Treatments consisted of both pre- and postemergence applications of ICIA-0051, alone and in combination with atrazine, and preemergence applications in combination with metolachlor. SC-0774 was applied preemergence, alone and in combination with atrazine. Results indicated good control of triazine-resistant (TR) smooth pigweed and other annual broadleaf weeds present with no adverse effects on crop vigor and yield with ICIA-0051. Generally, the addition of atrazine to ICIA-0051 improved weed control. SC-0774 provided good control of fall panicum, but generally poorer and less consistent control of giant ragweed, common ragweed, common lambsquarters, and ivyleaf and tall morningglory species.
Common Cocklebur (Xanthium strumarium) Interference in Snap Beans (Phaseolus vulgaris)
Authors: Neary Philip E. , Majek Bradley A.
Published: March 2018

The effect of common cocklebur interference on snap beans was investigated at Bridgeton, NJ, in 1987 and 1988. Snap bean yields were reduced by increasing weed densities. Yields were reduced 8 to 44% in 1987 and 2 to 55% in 1988 by full-season in-row weed densities ranging from 0.5 to 8/m2. One weed and 4 weeds/m2were the damage-threshold populations of common cocklebur with full-season interference in 1987 and 1988, respectively. The weed-free requirement, after planting, was to the unifoliolate stage of snap beans. Common cocklebur at 4 weeds/m2did not affect yield when snap beans were maintained weed free until the unifoliolate stage of snap beans. The critical duration of interference for common cocklebur emerging with snap beans was between the emergence and full-bloom stage of snap beans. Snap bean yield was not reduced with weed removal at full bloom.