scholarly journals Alternative Hosts in the Families Poaceae and Cyperaceae for Xanthomonas vasicola pv. vasculorum, Causal Agent of Bacterial Leaf Streak of Corn

2020 ◽  
Vol 110 (6) ◽  
pp. 1147-1152 ◽  
Author(s):  
T. Hartman ◽  
B. Tharnish ◽  
J. Harbour ◽  
G. Y. Yuen ◽  
T. A. Jackson-Ziems
Keyword(s):  
United States ◽  
Festuca Arundinacea ◽  
Field Experiments ◽  
The United States ◽  
Phleum Pratense ◽  
Schizachyrium Scoparium ◽  
Big Bluestem ◽  
Bacterial Leaf Streak ◽  
Alternative Hosts ◽  
Palm Species

The bacterial pathogen Xanthomonas vasicola pv. vasculorum was first reported in the United States causing bacterial leaf streak on Nebraska corn (Zea mays) in 2016. The bacterium is also known to cause disease in sugarcane, grain sorghum, broom bamboo, and various palm species. The objective of this study was to identify alternative hosts for X. vasicola pv. vasculorum among plants commonly found in corn growing areas of the United States. In repeated greenhouse experiments, 53 species of plants found in the United States that had not been tested previously for susceptibility to X. vasicola pv. vasculorum were inoculated with the pathogen and monitored for symptom development. Eleven species in the family Poaceae exhibited symptoms: oat (Avena sativa), rice (Oryza sativa), orchardgrass (Dactylis glomerata), indiangrass (Sorghastrum nutans), big bluestem (Andropogon gerardii), little bluestem (Schizachyrium scoparium), timothy (Phleum pratense), sand bluestem (Andropogon hallii), green foxtail (Setaria viridis), bristly foxtail (Setaria verticillata), and johnsongrass (Sorghum halepense). Yellow nutsedge (Cyperus esculentus) in the Cyperaceae also was a symptomatic host. In addition, endophytic colonization by X. vasicola pv. vasculorum was found in three asymptomatic alternative hosts: downy brome (Bromus tectorum), tall fescue (Festuca arundinacea), and western wheatgrass (Pascopyum smithii). Experiments were also conducted in the field to determine the potential for alternative hosts to become infected by natural inoculum. Symptoms developed only in big bluestem and bristly foxtail in field experiments. These results suggest that infection of alternative hosts by X. vasicola pv. vasculorum can occur, but infection rates might be limited by environmental conditions.

scholarly journals Interaction of dicamba, fluthiacet-methyl, and glyphosate for control of velvetleaf (Abutilon theopharsti) in dicamba/glyphosate-resistant soybean

2021 ◽  
pp. 1-21
Author(s):  
Jose H. S. de Sanctis ◽  
Amit J. Jhala
Keyword(s):  
United States ◽  
Field Experiments ◽  
The United States ◽  
Application Rate ◽  
Herbicide Application ◽  
Soybean Yield ◽  
Agronomic Crops ◽  
Split Plot ◽  
Main Plot ◽  
Biomass Reduction

Abstract Velvetleaf is an economically important weed in agronomic crops in Nebraska and the United States. Dicamba applied alone usually does not provide complete velvetleaf control, particularly when velvetleaf is greater than 15 cm tall. The objectives of this experiment were to evaluate the interaction of dicamba, fluthiacet-methyl, and glyphosate applied alone or in a mixture in two- or three-way combinations for velvetleaf control in dicamba/glyphosate-resistant (DGR) soybean and to evaluate whether velvetleaf height (≤ 12 cm or ≤ 20 cm) at the time of herbicide application influences herbicide efficacy, velvetleaf density, biomass, and soybean yield. Field experiments were conducted near Clay Center, Nebraska in 2019 and 2020. The experiment was arranged in a split-plot with velvetleaf height (≤ 12 cm or ≤ 20 cm) as the main plot treatment and herbicides as sub-plot treatment. Fluthiacet provided ≥ 94% velvetleaf control 28 d after treatment (DAT) and ≥ 96% biomass reduction regardless of application rate or velvetleaf height. Velvetleaf control was 31% to 74% at 28 DAT when dicamba or glyphosate was applied alone to velvetleaf ≤ 20 cm tall compared with 47% to 100% control applied to ≤ 12 cm tall plants. Dicamba applied alone to ≤ 20 cm tall velvetleaf provided < 75% control and < 87% biomass reduction 28 DAT compared with ≥ 90% control with dicamba at 560 g ae ha−1 + fluthiacet at 7.2 g ai ha−1 or glyphosate at 1,260 g ae ha−1. Dicmaba at 280 g ae ha−1 + glyphosate at 630 g ae ha−1 applied to ≤ 20 cm tall velvetleaf resulted in 86% control 28 DAT compared with the expected 99% control. The interaction of dicamba + fluthiacet + glyphosate was additive for velvetleaf control and biomass reduction regardless of application rate and velvetleaf height.

scholarly journals Field Evaluations of Leaf Spot Resistance and Yield in Peanut Genotypes in the United States and Bolivia

Plant Disease ◽  
2011 ◽  
Vol 95 (3) ◽  
pp. 263-268 ◽  
Author(s):  
S. K. Gremillion ◽  
A. K. Culbreath ◽  
D. W. Gorbet ◽  
B. G. Mullinix ◽  
R. N. Pittman ◽  
...  
Keyword(s):  
United States ◽  
Disease Resistance ◽  
Leaf Spot ◽  
Field Experiments ◽  
Disease Incidence ◽  
The United States ◽  
Yield Potential ◽  
Cercospora Arachidicola ◽  
Breeding Lines ◽  
Progress Curve

Field experiments were conducted in 2002 to 2006 to characterize yield potential and disease resistance in the Bolivian landrace peanut (Arachis hypogaea) cv. Bayo Grande, and breeding lines developed from crosses of Bayo Grande and U.S. cv. Florida MDR-98. Diseases of interest included early leaf spot, caused by the fungus Cercospora arachidicola, and late leaf spot, caused by the fungus Cercosporidium personatum. Bayo Grande, MDR-98, and three breeding lines, along with U.S. cvs. C-99R and Georgia Green, were included in split-plot field experiments in six locations across the United States and Bolivia. Whole-plot treatments consisted of two tebuconazole applications and a nontreated control. Genotypes were the subplot treatments. Area under the disease progress curve (AUDPC) for percent defoliation due to leaf spot was lower for Bayo Grande and all breeding lines than for Georgia Green at all U.S. locations across years. AUDPC for disease incidence from one U.S. location indicated similar results. Severity of leaf spot epidemics and relative effects of the genotypes were less consistent in the Bolivian experiments. In Bolivia, there were no indications of greater levels of disease resistance in any of the breeding lines than in Bayo Grande. In the United States, yields of Bayo Grande and the breeding lines were greater than those of the other genotypes in 1 of 2 years. In Bolivia, low disease intensity resulted in the highest yields in Georgia Green, while high disease intensity resulted in comparable yields among the breeding lines, MDR-98, and C-99R. Leaf spot suppression by tebuconazole was greater in Bolivia than in the United States. This result indicates a possible higher level of fungicide resistance in the U.S. population of leaf spot pathogens. Overall, data from this study suggest that Bayo Grande and the breeding lines may be desirable germplasm for U.S. and Bolivian breeding programs or production.

scholarly journals Consumer Preferences for Oyster Attributes: Field Experiments on Brand, Locality, and Growing Method

2017 ◽  
Vol 46 (2) ◽  
pp. 315-337 ◽  
Author(s):  
Maik Kecinski ◽  
Kent D. Messer ◽  
Lauren Knapp ◽  
Yosef Shirazi
Keyword(s):  
United States ◽  
Field Experiments ◽  
Consumer Preferences ◽  
Revealed Preference ◽  
The United States ◽  
Dichotomous Choice ◽  
Production Methods ◽  
The Past ◽  
Oyster Aquaculture ◽  
First Time

Oyster aquaculture has experienced tremendous growth in the United States over the past decade, but little is known about consumer preferences for oysters. This study analyzed preferences for oysters with varied combinations of brands, production locations, and production methods (aquaculture vs. wild-caught) using dichotomous choice, revealed preference economic field experiments. Results suggest significant and distinct differences in behavior between first-time and regular oyster consumers. While infrequent oyster consumers were drawn to oysters labeled as wild-caught, experienced oyster consumers preferred oysters raised via aquaculture. These findings will be valuable for growers and policymakers who invest in aquaculture to improve surrounding ecosystems.

Management of glyphosate-resistant Palmer amaranth (Amaranthus palmeri) in 2,4-D–, glufosinate-, and glyphosate-resistant soybean

2020 ◽  
pp. 1-8
Author(s):  
Chandrima Shyam ◽  
Parminder S. Chahal ◽  
Amit J. Jhala ◽  
Mithila Jugulam
Keyword(s):  
United States ◽  
Field Experiments ◽  
The United States ◽  
Palmer Amaranth ◽  
Amaranthus Palmeri ◽  
Soybean Yield ◽  
Chlorimuron Ethyl ◽  
Density And Biomass ◽  
Herbicide Programs ◽  
Biomass Reduction

Abstract Glyphosate-resistant (GR) Palmer amaranth is a problematic, annual broadleaf weed in soybean production fields in Nebraska and many other states in the United States. Soybean resistant to 2,4-D, glyphosate, and glufosinate (Enlist E3TM) has been developed and was first grown commercially in 2019. The objectives of this research were to evaluate the effect of herbicide programs applied PRE, PRE followed by (fb) late-POST (LPOST), and early-POST (EPOST) fb LPOST on GR Palmer amaranth control, density, and biomass reduction, soybean injury, and yield. Field experiments were conducted near Carleton, NE, in 2018, and 2019 in a grower’s field infested with GR Palmer amaranth in 2,4-D–, glyphosate-, and glufosinate-resistant soybean. Sulfentrazone + cloransulam-methyl, imazethapyr + saflufenacil + pyroxasulfone, and chlorimuron ethyl + flumioxazin + metribuzin applied PRE provided 84% to 97% control of GR Palmer amaranth compared with the nontreated control 14 d after PRE. Averaged across herbicide programs, PRE fb 2,4-D and/or glufosinate, and sequential application of 2,4-D or glufosinate applied EPOST fb LPOST resulted in 92% and 88% control of GR Palmer amaranth, respectively, compared with 62% control with PRE-only programs 14 d after LPOST. Reductions in Palmer amaranth biomass followed the same trend; however, Palmer amaranth density was reduced 98% in EPOST fb LPOST programs compared with 91% reduction in PRE fb LPOST and 76% reduction in PRE-only programs. PRE fb LPOST and EPOST fb LPOST programs resulted in an average soybean yield of 4,478 and 4,706 kg ha−1, respectively, compared with 3,043 kg ha−1 in PRE-only programs. Herbicide programs evaluated in this study resulted in no soybean injury. The results of this research illustrate that herbicide programs are available for the management of GR Palmer amaranth in 2,4-D–, glyphosate-, and glufosinate-resistant soybean.

Dry Pea (Pisum sativumL.) Response to Low Rates of Selected Foliar- and Soil-Applied Sulfonylurea and Growth Regulator Herbicides

1999 ◽  
Vol 13 (4) ◽  
pp. 753-758 ◽  
Author(s):  
Kassim Al-Khatib ◽  
Ajit Tamhane
Keyword(s):  
United States ◽  
Pisum Sativum ◽  
Growth Regulator ◽  
Field Experiments ◽  
The United States ◽  
Large Reduction ◽  
Soil Application ◽  
Effect On Yield ◽  
Plant Injury ◽  
Significant Injury

Field experiments on dry pea (Pisum sativum) were conducted at five locations across the United States in 1995 and 1996 to investigate the effects of low rates of chlorsulfuron, thifensulfuron, and dicamba applied postemergence and of chlorsulfuron, metsulfuron, and clopyralid applied preplant incorporated in the soil on pea plants. Although chlorsulfuron, thifensulfuron, and dicamba caused significant injury symptoms on pea plants, they had little effect on yield. The lowest rates of foliar applications that caused observable symptoms were 0.035, 0.086, and 1.56 g ai/ha for chlorsulfuron, thifensulfuron, and dicamba, respectively, whereas chlorsulfuron, thifensulfuron, and dicamba rates that reduced pea yield by 25% were 0.18, 1.36, and 25 g/ha, respectively. Clopyralid caused more injury symptoms than metsulfuron or chlorsulfuron with soil application. However, the lowest rates of chlorsulfuron, metsulfuron, and clopyralid that caused observable symptoms were lower than the rates that reduced yield. This study showed that pea plants can sustain some level of plant injury without a large reduction in yield.

Weed control and crop tolerance of micro-encapsulated acetochlor applied sequentially in glyphosate-resistant soybean

2015 ◽  
Vol 95 (5) ◽  
pp. 973-981 ◽  
Author(s):  
Amit J. Jhala ◽  
Mayank S. Malik ◽  
John B. Willis
Keyword(s):  
United States ◽  
Weed Control ◽  
Field Experiments ◽  
The United States ◽  
Soybean Yield ◽  
Application Timing ◽  
Common Waterhemp ◽  
Weed Density ◽  
Crop Tolerance ◽  
Green Foxtail

Jhala, A. J., Malik, M. S. and Willis, J. B. 2015. Weed control and crop tolerance of micro-encapsulated acetochlor applied sequentially in glyphosate-resistant soybean. Can. J. Plant Sci. 95: 973–981. Acetochlor, an acetamide herbicide, has been used for many years for weed control in several crops, including soybean. Micro-encapsulated acetochlor has been recently registered for preplant (PP), pre-emergence (PRE), and post-emergence (POST) application in soybean in the United States. Information is not available regarding the sequential application of acetochlor for weed control and soybean tolerance. The objectives of this research were to determine the effect of application timing of micro-encapsulated acetochlor applied in tank-mixture with glyphosate in single or sequential applications for weed control in glyphosate-resistant soybean, and to determine its impact on soybean injury and yields. Field experiments were conducted at Clay Center, Nebraska, in 2012 and 2013, and at Waverly, Nebraska, in 2013. Acetochlor tank-mixed with glyphosate applied alone PP, PRE, or tank-mixed with flumioxazin, fomesafen, or sulfentrazone plus chlorimuron provided 99% control of common waterhemp, green foxtail, and velvetleaf at 15 d after planting (DAP); however, control declined to ≤40% at 100 DAP. Acetochlor tank-mixed with glyphosate applied PRE followed by early POST (V2 to V3 stage of soybean) or late POST (V4 to V5 stage) resulted in ≥90% control of common waterhemp and green foxtail, reduced weed density to ≤2 plants m−2 and biomass to ≤12 g m−2, and resulted in soybean yields >3775 kg ha−1. The sequential applications of glyphosate plus acetochlor applied PP followed by early POST or late POST resulted in equivalent weed control to the best herbicide combinations included in this study and soybean yield equivalent to the weed free control. Injury to soybean was <10% in each of the treatments evaluated. Micro-encapsulated acetochlor can be a good option for soybean growers for controlling grasses and small-seeded broadleaf weeds if applied in a PRE followed by POST herbicide program in tank-mixture with herbicides of other modes of action.

Drawing Your Senator from a Jar:Term Length and Legislative Behavior

2015 ◽  
Vol 4 (2) ◽  
pp. 293-316 ◽  
Author(s):  
Rocío Titiunik
Keyword(s):  
United States ◽  
Field Experiments ◽  
The United States ◽  
Legislative Behavior ◽  
State Senators ◽  
Rare Opportunity

This paper studies the effects of term duration on legislative behavior using field experiments that occur in the Arkansas, Illinois, and Texas Senates in the United States. After mandatory changes in senate district boundaries, state senators are randomly assigned to serve either two-year or four-year terms, providing a rare opportunity to study legislative behavior experimentally. Despite important differences across states, when considered together, the results show that senators serving two years abstain more often, introduce fewer bills, and do not seem to be more responsive to their constituents than senators serving four years. In addition, senators serving shorter terms raise and spend significantly more money, although in those states where funds can be raised continuously during the legislative term, the differences arise only when the election is imminent.

scholarly journals Application of Airborne Passive Microwave Observations for Monitoring Inland Flooding Caused by Tropical Cyclones

2009 ◽  
Vol 26 (10) ◽  
pp. 2051-2070
Author(s):  
Courtney D. Buckley ◽  
Robbie E. Hood ◽  
Frank J. LaFontaine
Keyword(s):  
United States ◽  
Surface Water ◽  
Tropical Cyclone ◽  
Tropical Cyclones ◽  
Field Experiments ◽  
Vegetation Indices ◽  
The United States ◽  
Unmanned Aircraft ◽  
Passive Microwave ◽  
Inland Flooding

Abstract Inland flooding from tropical cyclones is a significant factor in storm-related deaths in the United States and other countries, with the majority of tropical cyclone fatalities recorded in the United States resulting from freshwater flooding. Information collected during National Aeronautics and Space Administration (NASA) tropical cyclone field experiments suggests that surface water and flooding can be detected and therefore monitored at a greater spatial resolution by using passive microwave airborne radiometers than by using satellite sensors. The 10.7-GHz frequency of the NASA Advanced Microwave Precipitation Radiometer (AMPR) has demonstrated high-resolution detection of anomalous surface water and flooding in numerous situations. In this study, an analysis of three cases is conducted utilizing satellite and airborne radiometer data. Data from the 1998 Third Convection and Moisture Experiment (CAMEX-3) are utilized to detect surface water during the landfalling Hurricane Georges in both the Dominican Republic and Louisiana. Another case studied was the landfalling Tropical Storm Gert in eastern Mexico during the Tropical Cloud Systems and Processes (TCSP) experiment in 2005. AMPR data are compared to topographic data and vegetation indices to evaluate the significance of the surface water signature visible in the 10.7-GHz information. The results illustrate the AMPR’s utility in monitoring surface water that current satellite-based passive microwave radiometers are unable to monitor because of their coarser resolutions. This suggests the benefit of a radiometer with observing frequencies less than 11 GHz deployed on a manned aircraft or unmanned aircraft system to provide early detection in real time of expanding surface water or flooding conditions.

Lignin and holocellulose relations during long-term decomposition of some forest litters. Long-term decomposition in a Scots pine forest. IV

1984 ◽  
Vol 62 (12) ◽  
pp. 2540-2550 ◽  
Author(s):  
Bjorn Berg ◽  
Gunnar Ekbohm ◽  
Charles McClaugherty
Keyword(s):  
United States ◽  
Scots Pine ◽  
Field Experiments ◽  
The United States ◽  
Pine Forest ◽  
Chemical Components ◽  
Asymptotic Value ◽  
Asymptotic Values ◽  
Scots Pine Forest

We investigated the relative changes in celluloses and lignin during decomposition of leaf and needle litters and wood in field experiments. The litter came from two different forest systems: one in the United States and one in Sweden. We found that the fraction of holocellulose in the total lignocellulose (Q) during decomposition approached an asymptotic value at which the disappearance of both the chemical components proceeded at the same rate. Different litter types approached different asymptotic values of Q. Possible implications of the finding are discussed.

Tolerance of Leafy Greens to Preemergence and Postemergence Herbicides

2005 ◽  
Vol 19 (3) ◽  
pp. 724-730 ◽  
Author(s):  
Jason K. Norsworthy ◽  
John P. Smith
Keyword(s):  
United States ◽  
Field Experiments ◽  
The United States ◽  
Leafy Greens ◽  
Hairy Nightshade ◽  
Direct Seeded ◽  
Turnip Greens ◽  
Common Purslane ◽  
Postemergence Herbicides ◽  
Large Crabgrass

Field experiments were conducted in 2003 and 2004 to determine the tolerance of direct-seeded leafy turnip greens, mustard greens, kale, and collard to selected preemergence and postemergence herbicides and to determine the efficacy of these herbicides against weeds that are common to the southeastern coastal plains of the United States. Pendimethalin applied preemergence controlled large crabgrass, goosegrass, carpetweed, and common purslane, but it injured turnip greens, mustard greens, kale, and collard. Dimethenamid at 0.31 and 0.63 kg ai/ha controlled large crabgrass and goosegrass but did not control hairy nightshade or common purslane at the lower rate. In 2003, dimethenamid at 0.63 kg/ha injured mustard greens, kale, and collard more than 40%. S-metolachlor applied preemergence at 0.45 kg ai/ha controlled large crabgrass, goosegrass, hairy nightshade, and common purslane while causing little or no injury to turnip greens, mustard greens, kale, and collard. Clopyralid at 0.10 kg ai/ha controlled common lambsquarters 76 to 95% and hairy nightshade 93% but did not control carpetweed, common purslane, large crabgrass, and goosegrass. Turnip greens, mustard greens, kale, and collard generally were tolerant of clopyralid, but mustard was injured 29% in 2003. Phenmedipham alone or in combination with desmedipham injured mustard greens 54 to 82% in 2003 and failed to control weeds. Of the herbicides evaluated, S-metolachlor provides the best potential to improve weed control in direct-seeded leafy greens in the southeastern United States.

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