scholarly journals Overwintering of Sclerotium rolfsii and S. rolfsii var. delphinii in Different Latitudes of the United States

Plant Disease ◽  
2008 ◽  
Vol 92 (5) ◽  
pp. 719-724 ◽  
Author(s):  
Z. Xu ◽  
M. L. Gleason ◽  
D. S. Mueller ◽  
P. D. Esker ◽  
C. A. Bradley ◽  
...  
Keyword(s):  
United States ◽  
North Carolina ◽  
North Dakota ◽  
Southeastern United States ◽  
Sclerotium Rolfsii ◽  
Climate Extremes ◽  
Bare Soil ◽  
The United States ◽  
Southern United States ◽  
Northern United States

Previously known only from the southern United States, hosta petiole rot recently appeared in the northern United States. Sclerotium rolfsii var. delphinii is believed to be the predominant petiole rot pathogen in the northern United States, whereas S. rolfsii is most prevalent in the southern United States. In order to test the hypothesis that different tolerance to climate extremes affects the geographic distribution of these fungi, the survival of S. rolfsii and S. rolfsii var. delphinii in the northern and southeastern United States was investigated. At each of four locations, nylon screen bags containing sclerotia were placed on the surface of bare soil and at 20-cm depth. Sclerotia were recovered six times from November 2005 to July 2006 in North Dakota and Iowa, and from December 2005 to August 2006 in North Carolina and Georgia. Survival was estimated by quantifying percentage of sclerotium survival on carrot agar. Sclerotia of S. rolfsii var. delphinii survived until at least late July in all four states. In contrast, no S. rolfsii sclerotia survived until June in North Dakota or Iowa, whereas 18.5% survived until August in North Carolina and 10.3% survived in Georgia. The results suggest that inability to tolerate low temperature extremes limits the northern range of S. rolfsii.

scholarly journals Grafting Tomato to Manage Bacterial Wilt Caused by Ralstonia solanacearum in the Southeastern United States

Plant Disease ◽  
2012 ◽  
Vol 96 (7) ◽  
pp. 973-978 ◽  
Author(s):  
C. L. Rivard ◽  
S. O'Connell ◽  
M. M. Peet ◽  
R. M. Welker ◽  
F. J. Louws
Keyword(s):  
United States ◽  
North Carolina ◽  
Bacterial Wilt ◽  
Ralstonia Solanacearum ◽  
Southeastern United States ◽  
The United States ◽  
Tomato Production ◽  
Progress Curve ◽  
Grafting Onto ◽  
Wilt Incidence

Bacterial wilt, caused by Ralstonia solanacearum, can result in severe losses to tomato (Solanum lycopersicum) growers in the southeastern United States, and grafting with resistant rootstocks may be an effective strategy for managing this disease. However, R. solanacearum populations maintain considerable diversity, and little information is known regarding the efficacy of commercially available rootstocks to reduce bacterial wilt incidence and subsequent crop loss in the United States. In this study, tomato plants grafted onto ‘Dai Honmei’ and ‘RST-04-105-T’ rootstocks had significantly lower area under the disease progress curve (AUDPC) values compared with nongrafted plants (P < 0.05). Across three locations in North Carolina, final bacterial wilt incidence for non- and self-grafted plants was 82 ± 14 to 100%. In contrast, bacterial wilt incidence for the grafted plants was 0 to 65 ± 21%. Final bacterial wilt incidence of plants grafted with Dai Honmei rootstock was 0 and 13 ± 3% at two locations in western North Carolina but 50 ± 3% at a third site in eastern North Carolina. Similarly, grafting onto RST-04-105-T rootstock significantly reduced AUDPC values at two of the three locations (P < 0.05) compared with that of the nongrafted plants, but performed poorly at the third site. Total fruit yields were significantly increased by grafting onto resistant rootstocks at all three sites (P < 0.05). Regression analyses indicated that yield was significantly negatively correlated with bacterial wilt AUDPC values (R2 was 0.4048 to 0.8034), and the use of resistant rootstocks enabled economically viable tomato production in soils naturally infested with R. solanacearum.

scholarly journals First Report of Stem and Root Rot of Stevia Caused by Sclerotium rolfsii in North Carolina

Plant Disease ◽  
2014 ◽  
Vol 98 (7) ◽  
pp. 1005-1005 ◽  
Author(s):  
A. Koehler ◽  
H. Shew
Keyword(s):  
United States ◽  
North Carolina ◽  
Root Rot ◽  
Mycelial Growth ◽  
Sclerotium Rolfsii ◽  
Pathogenic Fungi ◽  
The United States ◽  
Penicillin G ◽  
Stem Tissue ◽  
First Report

Stevia (Stevia rebaundia) is an emerging crop in the United States. Once established, the crop is grown for 3 to 5 years and is typically harvested twice per growing season. Stevia leaves contain multiple glycosides that are used as a natural noncaloric sweetener that was approved by the USDA in 2008 as a sugar substitute. In commercial plantings of Stevia in North Carolina, wilting and death of plants in first- and second-year plantings were observed in 2012 and 2013. Diseased plants were observed in multiple counties in the state, with first symptoms observed in May of each year and continuing through the summer months. Prior to Stevia, these fields had been planted primarily in a corn-soybean rotation. Symptoms began as moderate to severe wilting of young shoots and chlorosis of leaves, rapidly followed by death of stems and rotting of roots. White mycelial growth was frequently observed at the base of stem tissue. Theses characteristic hyphae of Sclerotium rolfsii were often accompanied by the presence of abundant white to brown sclerotia. Isolations from infected root and stem tissue were made on potato dextrose agar amended with 50 μg/ml of streptomycin sulfate and penicillin G. Isolations from diseased tissue yielded characteristic white hyphae of S. rolfsii (1,3). Numerous sclerotia 0.5 to 2 mm in diameter developed following 4 to 7 days of mycelial growth. Sclerotia were initially white and melanized turning brown with age. To verify pathogenicity, 10-week-old Stevia seedlings were transplanted in 10-cm diameter pots containing sterile 1:1:1 sand, loam, media mix. Inoculum consisted of oat grains infested with one isolate obtained from the field plants. Oats were sterilized on three consecutive days and then inoculated with colonized agar plugs of S. rolfsii. Oats were incubated at room temperature to allow the fungus to thoroughly colonize the oats. Three infested oat grains were added to each test pot and plants were then observed over a 3-week period. Symptoms were observed within 5 days on most plants and included chlorotic leaves, bleached stems, wilting, and necrotic roots. White mycelium and abundant sclerotia were found at the base of plants. Uninoculated plants did not develop any symptoms. This is the first report of S. rolfsii on Stevia in the United States. Kamalakannan et al. (2) reported a root rot disease of Stevia in India and confirmed S. rolfsii as the causal agent. References: (1) R. Aycock. N.C. Agr. Exp. St. Tech. Bull. No. 174, 1966. (2) A. Kamalakannan et al. Plant Pathol. 56:350, 2007. (3) J. E. M. Mordue. Corticium rolfsii. CMI Descriptions of Pathogenic Fungi and Bacteria No. 410. CAB International, Wallingford, UK, 1974.

scholarly journals Italianness in the United States between migrants’ informal gardening practices and agricultural diplomacy (1880–1912)

Modern Italy ◽  
2021 ◽  
pp. 1-17
Author(s):  
Gilberto Mazzoli
Keyword(s):  
United States ◽  
Environmental History ◽  
Rural Areas ◽  
Food Production ◽  
East Coast ◽  
The United States ◽  
Southern United States ◽  
Mass Migration ◽  
Us Cities ◽  
Political Radicalism

During the Age of Mass Migration more than four million Italians reached the United States. The experience of Italians in US cities has been widely explored: however, the study of how migrants adjusted in relation to nature and food production is a relatively recent concern. Due to a mixture of racism and fear of political radicalism, Italians were deemed to be undesirable immigrants in East Coast cities and American authorities had long perceived Italian immigrants as unclean, unhealthy and carriers of diseases. As a flipside to this narrative, Italians were also believed to possess a ‘natural’ talent for agriculture, which encouraged Italian diplomats and politicians to propose the establishment of agricultural colonies in the southern United States. In rural areas Italians could profit from their agricultural skills and finally turn into ‘desirable immigrants’. The aim of this paper is to explore this ‘emigrant colonialism’ through the lens of environmental history, comparing the Italian and US diplomatic and public discourses on the potential and limits of Italians’ agricultural skills.

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 Effects from Early Planting of Late-Maturing Sunflowers on Damage from Primary Insect Pests in the United States

Helia ◽  
2016 ◽  
Vol 39 (64) ◽  
pp. 45-56 ◽  
Author(s):  
J. R. Prasifka ◽  
L. F. Marek ◽  
D. K. Lee ◽  
S. B. Thapa ◽  
V. Hahn ◽  
...  
Keyword(s):  
United States ◽  
North Dakota ◽  
Sunflower Seed ◽  
Insect Pests ◽  
The United States ◽  
Total Percentage ◽  
History Of ◽  
Smicronyx Fulvus ◽  
Sunflower Moth ◽  
Homoeosoma Electellum

AbstractDelayed planting is recommended to reduce damage from sunflower insect pests in the United States, including the sunflower moth, Homoeosoma electellum (Hulst) and banded sunflower moth, Cochylis hospes Walsingham. However, in some locations, planting earlier or growing later-maturing hybrids could improve yield or oil content of sunflowers which would partially offset any added costs from insect pests or their management. Because the abundance and distribution of some sunflower insects have changed since recommendations for delayed planting were developed, experimental plots were grown in 2012 and 2013 at sites in North Dakota, Nebraska, Iowa, and Illinois. Sunflowers were planted two to four weeks earlier than normal, including hybrids that flower two to three weeks later than elite commercial hybrids. The sum of seed damaged by sunflower moth, banded sunflower moth, and red sunflower seed weevil, Smicronyx fulvus LeConte, (i. e., total percentage) was influenced by location, but not the relative maturity of tested entries. However, when damage attributed solely to the red sunflower seed weevil was analyzed, more damaged seed were found for late-maturing entries in North Dakota and Nebraska. In addition to the trial data, current pest populations are lower than when delayed planting was first recommended and insecticide use during sunflower bloom is both common and effective. Together, these observations suggest factoring insect pests into planting time decisions may be unnecessary, except for areas with a history of problems with severe pests that cannot be managed using insecticides (e. g., sunflower midge, Contarinia schulzi Gagné).

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