Temperature Factors Limiting the Spread of Cogongrass (Imperata cylindrica) and Torpedograss (Panicum repens)

Weed Science ◽  
1988 ◽  
Vol 36 (1) ◽  
pp. 49-55 ◽  
Author(s):  
John W. Wilcut ◽  
Bryan Truelove ◽  
Donald E. Davis ◽  
John C. Williams
Keyword(s):  
United States ◽  
Southeastern United States ◽  
Field Studies ◽  
The United States ◽  
Imperata Cylindrica ◽  
Coastal Plains ◽  
Night Temperature ◽  
Temperature Regimes ◽  
Panicum Repens ◽  
Common Bermudagrass

Greenhouse, growth chamber, and field studies were conducted to determine effects of temperature on the potential of cogongrass (Imperata cylindricaL. Beauv. # IMPCY) and torpedograss (Panicum repensL. # PANRE) to spread beyond present distribution in the Lower Coastal Plains of Southeastern United States. Johnsongrass [Sorghum halepense(L.) Pers. # SORHA] was included in the study for comparative purposes. Growth of each species was greater with day/night temperature regimes of 30/25 C than with 27/22 or 24/18 C. Apical six-node-long rhizome fragments of all three species were killed by a 24-h exposure to −4.5 C. Johnsongrass produced at least three to five times more dry matter than either cogongrass or torpedograss. Order of interspecific competitiveness under 30/25, 27/22, and 24/18 C day/night temperature regimes was johnsongrass > torpedograss > cogongrass. After 2 yr, johnsongrass and torpedograss competition reduced common bermudagrass [Cyndon dactylon(L.) Pers. # CYNDA] yield by 99 and 37%, respectively, while cogongrass competition did not affect common bermudagrass yield. It is concluded that cogongrass and torpedograss are unlikely to spread into more temperate regions of the United States. However, both species are apt to become even more widespread and troublesome in the Lower Coastal Plains of Southeastern United States.

Cogongrass,Imperata cylindrica, in the United States

1993 ◽  
Vol 7 (4) ◽  
pp. 1005-1009 ◽  
Author(s):  
Charles T. Bryson ◽  
Richard Carter
Keyword(s):  
United States ◽  
Environmental Conditions ◽  
Southeastern United States ◽  
The United States ◽  
Imperata Cylindrica ◽  
Physical Injury ◽  
Light Water ◽  
Eastern Hemisphere ◽  
Introduced Range ◽  
Variable Species

Cogongrass [Imperata cylindrica(L.) Beauv. # IMPCY] is an aggressive, pernicious, rhizomatous perennial in the Poaceae (Graminae). It is native to tropical and subtropical areas of the eastern hemisphere. Introductions of cogongrass into the southeastern United States have been tracked to several separate sources, both accidental and intentional, in southern Alabama, southern Mississippi, and Florida. It was found to be unacceptable for use as a forage and in erosion control. Cogongrass is a highly variable species and has adapted to a variety of environmental conditions in its native and introduced range. Today cogongrass infests 200 million ha in Asia, several thousand ha in the Southeastern United States, and over 500 million ha worldwide. It has been reported to be a weed problem in many annual and perennial crops. In addition to competing for light, water and nutrients, cogongrass interference is caused by alleopathy and physical injury when rhizome apices penetrate crop roots, bulbs, and tubers. Holm et al. designated cogongrass as the world's seventh worst weed.

Hunting the eagle killer: A cyanobacterial neurotoxin causes vacuolar myelinopathy

Science ◽  
2021 ◽  
Vol 371 (6536) ◽  
pp. eaax9050
Author(s):  
Steffen Breinlinger ◽  
Tabitha J. Phillips ◽  
Brigette N. Haram ◽  
Jan Mareš ◽  
José A. Martínez Yerena ◽  
...  
Keyword(s):  
United States ◽  
Aquatic Vegetation ◽  
Southeastern United States ◽  
Hydrilla Verticillata ◽  
Toxin Production ◽  
The United States ◽  
Biosynthetic Gene Cluster ◽  
Biosynthetic Gene ◽  
Bald Eagles ◽  
Cyanobacterial Species

Vacuolar myelinopathy is a fatal neurological disease that was initially discovered during a mysterious mass mortality of bald eagles in Arkansas in the United States. The cause of this wildlife disease has eluded scientists for decades while its occurrence has continued to spread throughout freshwater reservoirs in the southeastern United States. Recent studies have demonstrated that vacuolar myelinopathy is induced by consumption of the epiphytic cyanobacterial species Aetokthonos hydrillicola growing on aquatic vegetation, primarily the invasive Hydrilla verticillata. Here, we describe the identification, biosynthetic gene cluster, and biological activity of aetokthonotoxin, a pentabrominated biindole alkaloid that is produced by the cyanobacterium A. hydrillicola. We identify this cyanobacterial neurotoxin as the causal agent of vacuolar myelinopathy and discuss environmental factors—especially bromide availability—that promote toxin production.

scholarly journals Fungicide Rotation Programs for Managing Phytophthora Fruit Rot of Watermelon in Southeastern United States

2017 ◽  
Vol 18 (1) ◽  
pp. 28-34 ◽  
Author(s):  
Chandrasekar (Shaker) S. Kousik ◽  
Pingsheng Ji ◽  
Daniel S. Egel ◽  
Lina M. Quesada-Ocampo
Keyword(s):  
United States ◽  
South Carolina ◽  
Phytophthora Capsici ◽  
Southeastern United States ◽  
Heavy Rain ◽  
Integrated Approach ◽  
The United States ◽  
Fruit Rot ◽  
Management Options ◽  
Before And After

About 50% of the watermelons in the United States are produced in the southeastern states, where optimal conditions for development of Phytophthora fruit rot prevail. Phytophthora fruit rot significantly limits watermelon production by causing serious yield losses before and after fruit harvest. Efficacy of fungicide rotation programs and Melcast-scheduled sprays for managing Phytophthora fruit rot was determined by conducting experiments in Phytophthora capsici-infested fields at three locations in southeastern United States (North Carolina, South Carolina, and Georgia). The mini seedless cultivar Wonder and seeded cultivar Mickey Lee (pollenizer) were used. Five weekly applications of fungicides were made at all locations. Significant fruit rot (53 to 91%, mean 68%) was observed in the nontreated control plots in all three years (2013 to 2015) and across locations. All fungicide rotation programs significantly reduced Phytophthora fruit rot compared with nontreated controls. Overall, the rotation of Zampro alternated with Orondis was highly effective across three locations and two years. Rotations of Actigard followed by Ranman+Ridomil Gold, Presidio, V-10208, and Orondis, or rotation of Revus alternated with Presidio were similarly effective. Use of Melcast, a melon disease-forecasting tool, may occasionally enable savings of one spray application without significantly impacting control. Although many fungicides are available for use in rotations, under very heavy rain and pathogen pressure, the fungicides alone may not offer adequate protection; therefore, an integrated approach should be used with other management options including well-drained fields.

scholarly journals Efficacy of a novel topical combination of esafoxolaner, eprinomectin and praziquantel against fleas in cats, under field conditions

Parasite ◽  
2021 ◽  
Vol 28 ◽  
pp. 22 ◽  
Author(s):  
Eric Tielemans ◽  
Tomoko Otsuki ◽  
Tara Cheesman ◽  
Fiona Selmes ◽  
Anthony Pfefferkorn ◽  
...  
Keyword(s):  
United States ◽  
Field Studies ◽  
The United States ◽  
Positive Control ◽  
Control Group ◽  
The Novel ◽  
Domestic Cats ◽  
Label Dose ◽  
Treatment Tolerance ◽  
Significant Health

Esafoxolaner is a purified afoxolaner enantiomer with insecticidal and acaricidal properties. It is combined with eprinomectin and praziquantel, nematodicidal and cestodicidal compounds, in a novel topical endectoparasiticide formulation for cats. This novel formulation was tested in four field studies, in the United States, Europe, Japan and Australia. In all studies, naturally flea-infested domestic cats were treated with the novel formulation at the label dose and conditions of use. The main objective, identical in the four studies, was to assess efficacy on fleas, based on comparison of mean number of fleas found on infested cats before and one month after treatment. Tolerance to the product was also evaluated in the four studies. Otherwise, the studies had some differences in their design and secondary objectives, for example testing for a reduction in flea infestation-related cutaneous signs, testing of one treatment or of three monthly treatments, and use of a positive control group. In the four studies, a total of 307 cats were treated with the novel formulation. The reduction of fleas one month after treatment was 97.7%, 98.8%, 100% and 99.7% in the United States, Europe, Japan and Australia, respectively. There were no significant health abnormalities attributed to treatment in any of the studies.

scholarly journals Cold Hardiness and Vernal Budbreak of Rhamnus caroliniana and the Invasive Rhamnus cathartica

2006 ◽  
Vol 131 (3) ◽  
pp. 345-351 ◽  
Author(s):  
J. Ryan Stewart ◽  
William R. Graves ◽  
Reid D. Landes
Keyword(s):  
United States ◽  
Water Stress ◽  
Cold Hardiness ◽  
Southeastern United States ◽  
The United States ◽  
Rhamnus Cathartica ◽  
Small Tree ◽  
Natural Distribution ◽  
Ecological Problems ◽  
Managed Landscapes

Carolina buckthorn [Rhamnus caroliniana Walt. or Frangula caroliniana (Walt.) Gray] is an attractive and water-stress-resistant shrub or small tree distributed extensively in the southeastern United States that merits use in managed landscapes. Due to substantial climatic differences within its distribution (30-year normal midwinter minima range from 13 to -8 °C), selection among provenances based on differences in cold hardiness is warranted. Before selections are marketed, the potential of carolina buckthorn to be invasive also merits investigation. Ecological problems resulting from the introduction of Rhamnus L. species in the United States, most notably the dominance of R. cathartica L. (common buckthorn) over neighboring taxa, are due in part to early budbreak. Consequently, we investigated depth of cold hardiness and vernal budbreak of carolina buckthorn and common buckthorn. Stem samples of carolina buckthorn and common buckthorn collected in midwinter survived temperatures as low as -21 and -24 °C, respectively. Although the cold hardiness of carolina buckthorns from Missouri was greater than that of carolina buckthorns from Ohio and Texas on 2 Apr. 2003, there were no differences in cold hardiness of stems from Missouri and Texas on all three assessment dates in the second experiment. All plants survived at both field locations except for the carolina buckthorns from southern Texas planted in Iowa, which showed 0% and 17% survival in 2003 and 2004, respectively. Budbreak of both species with and without mulch in Ames, Iowa, was recorded from 9 Apr. to 10 May 2002. Mean budbreak of common buckthorn was 5.7 days earlier than budbreak of carolina buckthorn, and buds of mulched carolina buckthorns broke 4.2 days earlier than did buds of unmulched carolina buckthorns. We conclude that the cold hardiness of carolina buckthorn is sufficient to permit the species to be planted outside of its natural distribution. Populations of carolina buckthorn in Ohio and Missouri should be the focus of efforts to select genotypes for use in regions with harsh winters. Phenology of its budbreak suggests carolina buckthorn will not be as invasive as common buckthorn, but evaluation of additional determinants of invasiveness is warranted.

Ethylene: A Witchweed Seed Germination Stimulant

Weed Science ◽  
1975 ◽  
Vol 23 (5) ◽  
pp. 433-436 ◽  
Author(s):  
Robert E. Eplee
Keyword(s):  
United States ◽  
Seed Germination ◽  
Clay Soil ◽  
Soil Surface ◽  
Field Studies ◽  
The United States ◽  
Major Contributor ◽  
Single Treatment ◽  
Striga Asiatica ◽  
Heavy Clay

Ethylene gas (C2H4) was found to stimulate the germination of witchweed [Striga asiatica(L.) O. Kuntze] seeds. Ethylene diffuses greater than 120 cm horizontally from point of injection and more than 90 cm below the soil surface. Rates of 0.42 kg/ha induced germination of witchweed seeds in sandy soil; but 1.1 kg/ha is required on a heavy clay soil. Witchweed seeds respond to ethylene after a period of preconditioning that is necessary to break dormancy. Under field conditions in the Carolinas, maximum response of seeds to ethylene occurs between late April and late July. Field studies indicate a 90% reduction in viable witchweed seeds occurs where a single treatment with ethylene has been applied. The use of ethylene appears now to be a major contributor toward the eventual eradication of witchweed from the United States.

scholarly journals Cry Wolf Effect? Evaluating the Impact of False Alarms on Public Responses to Tornado Alerts in the Southeastern United States

2019 ◽  
Vol 11 (3) ◽  
pp. 549-563 ◽  
Author(s):  
JungKyu Rhys Lim ◽  
Brooke Fisher Liu ◽  
Michael Egnoto
Keyword(s):  
United States ◽  
False Alarm ◽  
Protective Action ◽  
Southeastern United States ◽  
The United States ◽  
False Alarms ◽  
Protective Behavior ◽  
Tornado Warnings ◽  
Research Findings ◽  
The Impact

Abstract On average, 75% of tornado warnings in the United States are false alarms. Although forecasters have been concerned that false alarms may generate a complacent public, only a few research studies have examined how the public responds to tornado false alarms. Through four surveys (N = 4162), this study examines how residents in the southeastern United States understand, process, and respond to tornado false alarms. The study then compares social science research findings on perceptions of false alarms to actual county false alarm ratios and the number of tornado warnings issued by counties. Contrary to prior research, findings indicate that concerns about false alarm ratios generating a complacent public may be overblown. Results show that southeastern U.S. residents estimate tornado warnings to be more accurate than they are. Participants’ perceived false alarm ratios are not correlated with actual county false alarm ratios. Counterintuitively, the higher individuals perceive false alarm ratios and tornado alert accuracy to be, the more likely they are to take protective behavior such as sheltering in place in response to tornado warnings. Actual country false alarm ratios and the number of tornado warnings issued did not predict taking protective action.

scholarly journals The Impact of Bt Corn on Aflatoxin-Related Insurance Claims in the United States

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jina Yu ◽  
David A. Hennessy ◽  
Felicia Wu
Keyword(s):  
United States ◽  
Inverse Correlation ◽  
Field Studies ◽  
The United States ◽  
Economic Benefits ◽  
Aflatoxin Contamination ◽  
Economic Losses ◽  
Bt Corn ◽  
Insurance Claims ◽  
The Impact

Abstract Previous field studies have reached no collective consensus on whether Bt corn, one of the most commonly planted transgenic crops worldwide, has significantly lower aflatoxin levels than non-Bt isolines. Aflatoxin, a mycotoxin contaminating corn and other commodities, causes liver cancer in humans and can pose severe economic losses to farmers. We found that from 2001–2016, a significant inverse correlation existed between Bt corn planting and aflatoxin-related insurance claims in the United States, when controlling for temperature and drought. Estimated benefits of aflatoxin reduction resulting from Bt corn planting are about $120 million to $167 million per year over 16 states on average. These results suggest that Bt corn use is an important strategy in reducing aflatoxin risk, with corresponding economic benefits. If the same principles hold true in other world regions, then Bt corn hybrids adapted to diverse agronomic regions may have a role in reducing aflatoxin in areas prone to high aflatoxin contamination, and where corn is a dietary staple.

scholarly journals Long-Term Timber Contracts in the Southeastern United States: Updating the Primer Valuation Framework

2020 ◽  
Vol 66 (6) ◽  
pp. 653-665
Author(s):  
Hector I Restrepo ◽  
Bin Mei ◽  
Bronson P Bullock
Keyword(s):  
United States ◽  
Interest Rates ◽  
Southeastern United States ◽  
Price Volatility ◽  
Forest Products ◽  
The United States ◽  
Raw Material ◽  
Conditional Volatility ◽  
Material Supply

Abstract Timberland ownership has drastically changed in the United States since the 1980s, driven by the divestitures of vertically integrated forest products companies. Having sold their timberland, forest products companies have exposed themselves more to the risk of raw material supply. To hedge against this risk, forest products companies usually use long-term timber contracts (LTTC). The objective of this article is to update the valuation framework for LTTCs proposed by Shaffer (1984) by including alternative option price models and refining the estimates of some key economic variables. In particular, conditional volatility from the generalized autoregressive conditional heteroscedasticity model and quasi-conditional volatility from rolling estimation windows, in addition to simple standard deviation, are used for the volatility estimates in the option pricing models. Contrary to the previous result by Shaffer (1984), our analysis suggests that LTTCs that were once profitable for forest products companies in the 1980s are no longer so under current market conditions. This is primarily because both timber price volatility and the risk-free interest rates have declined significantly. Thus, to be better off, forest products companies need to either lower the administration and management costs of those LTTCs or rely more on the open market for timber procurement. Study Implications: Forest products companies have traditionally relied on long-term timber contracts (LTTC) negotiated with forest landowners to mitigate the risk of raw material supply. The value of these LTTCs highly depends on the economic context. This research provides some insights into the valuation of LTTCs in the southeastern United States. Forest products companies can use this updated framework to aid their decisionmaking in timber procurement.

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