Occurrence of Transgenic Feral Alfalfa (Medicago sativa subsp. sativa L.) in Alfalfa Seed Production Areas in the United States

To the best of our knowledge, this is the first report of GRSV infecting tomatillo and eggplant, and it is the first report of GRSV infecting pepper in the United States. This first identification of GRSV-infected crop plants in commercial fields in Palm Beach and Manatee Counties demonstrates the continuing geographic spread of the virus into additional vegetable production areas of Florida. This information indicates that a wide range of solanaceous plants is likely to be infected by this emerging viral pathogen in Florida and beyond. Accepted for publication 27 June 2011. Published 25 July 2011.

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Verticillium Wilt in Spinach Seed Production

Plant Disease ◽

10.1094/pd-89-0004 ◽

2005 ◽

Vol 89 (1) ◽

pp. 4-11 ◽

Cited By ~ 58

Author(s):

Lindsey J. du Toit ◽

Mike L. Derie ◽

Pablo Hernandez-Perez

Keyword(s):

United States ◽

Pacific Northwest ◽

Seed Production ◽

Verticillium Wilt ◽

Spinacia Oleracea ◽

Seed Transmission ◽

The United States ◽

Male And Female ◽

Systemic Movement ◽

The Pacific

There are no previous reports of Verticillium wilt in fresh and processing spinach (Spinacia oleracea) crops in the United States. In 2002, a hybrid spinach seed crop in the Pacific Northwest developed late-season wilt symptoms. Assays of the harvested seed and stock seed of the male and female parents revealed 59.5, 44.0, and 1.5%, respectively, were infected with Verticillium dahliae. Assays of 13 stock or commercial seed lots grown in 2002 and 62 commercial lots harvested in 2003 in Denmark, Holland, New Zealand, and the United States revealed the prevalence of Verticillium spp. in commercial spinach seed. Sixty-eight lots (89%) were infected with Verticillium spp. at incidences ranging from 0.3 to 84.8%. Five spinach seed isolates of V. dahliae were pathogenic on each of three spinach cultivars by root-dip inoculation. V. dahliae was detected on 26.4% of the seed from 7 of 11 inoculated plants but on none of the seed from 6 control plants, demonstrating systemic movement of V. dahliae. Seed-to-seed transmission was also demonstrated by planting naturally infected seed lots. This is the first report of Verticillium wilt of spinach in the primary region of spinach seed production in the United States.

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Characterization of Leaf Spot Pathogens from Several Spinach Production Areas in the United States

Plant Disease ◽

10.1094/pdis-11-19-2450-re ◽

2020 ◽

Vol 104 (7) ◽

pp. 1994-2004

Author(s):

Bo Liu ◽

Larry Stein ◽

Kimberly Cochran ◽

Lindsey J. du Toit ◽

Chunda Feng ◽

...

Keyword(s):

United States ◽

South Carolina ◽

Leaf Spot ◽

The United States ◽

Leaf Damage ◽

Leaf Spots ◽

Pathogenicity Tests ◽

Agar Media ◽

Production Areas

Leaf spot diseases have become a major concern in spinach production in the United States. Determining the causal agents of leaf spots on spinach, their prevalence and pathogenicity, and fungicide efficacy against these pathogens is vital for effective disease management. Spinach leaves with leaf spots were collected from Texas, California, Arizona, and South Carolina from 2016 to 2018, incubated in a moist chamber, and plated on potato dextrose and tryptic soy agar media. Fungal and bacterial colonies recovered were identified based on morphology and sequence analysis of the internal transcribed spacer rDNA and 16S rRNA, respectively. Two predominant genera were isolated: (i) Colletotrichum spp., which were identified to species based on sequences of both introns of the glutamate synthetase (GS-I) and glyceraldehyde-3-phosphate dehydrogenase (gapdh-I) genes; and (ii) Stemphylium spp., identified to species based on sequences of the gapdh and calmodulin (cmdA) genes. Anthracnose (Colletotrichum spinaciae) and Stemphylium leaf spot (Stemphylium vesicarium and S. beticola) were the predominant diseases. Additional fungi recovered at very limited frequencies that were also pathogenic to spinach included Colletotrichum coccodes, C. truncatum, Cercospora beticola, and Myrothecium verrucaria. All of the bacterial isolates were not pathogenic on spinach. Pathogenicity tests showed that C. spinaciae, S. vesicarium, and S. beticola caused significant leaf damage. The fungicides Bravo WeatherStik (chlorothalonil), Dithane F-45 (mancozeb), Cabrio (pyraclostrobin), and Merivon (fluxapyroxad and pyraclostrobin) were highly effective at reducing leaf spot severity caused by an isolate of each of C. spinaciae and S. vesicarium, when inoculated individually and in combination.

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Assessment of Epidemic Potential of Soybean Rust in the United States

Plant Disease ◽

10.1094/pd-89-0678 ◽

2005 ◽

Vol 89 (6) ◽

pp. 678-682 ◽

Cited By ~ 29

Author(s):

S. Pivonia ◽

X. B. Yang ◽

Z. Pan

Keyword(s):

United States ◽

The United States ◽

Soybean Rust ◽

Phakopsora Pachyrhizi ◽

Long Distance Dispersal ◽

Long Distance ◽

Climate Conditions ◽

Soybean Production ◽

Critical Components ◽

Production Areas

This article assesses the epidemic potential of soybean rust (Phakopsora pachyrhizi) in the United States. In the assessment, there are three critical components of uncertainty: (i) suitability of climate conditions in production areas for soybean rust epidemics; (ii) likelihood of establishment of the fungus in North America; and (iii) the seasonal dispersal potential of the pathogen from overwintering regions to major soybean production regions. Assessments on the first and second components suggest soybean rust epidemics are likely in the United States, and the certainty of the third component is yet to be determined. Comparison of epidemiological factors for soybean rust in soybean production regions between China and the United States shows a complicated picture with the United States having factors that both increase and decrease risk. Future investigation of risk components—incipience in the field and long-distance dispersal—is needed.

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EFFECTS OF ESTABLISHMENT METHOD AND A RAPESEED COMPANION CROP ON ALFALFA SEED YIELD

Canadian Journal of Plant Science ◽

10.4141/cjps87-037 ◽

1987 ◽

Vol 67 (1) ◽

pp. 263-266 ◽

Cited By ~ 1

Author(s):

J. WADDINGTON ◽

N. MALIK

Keyword(s):

Medicago Sativa ◽

Seed Production ◽

Seed Yield ◽

Brassica Campestris ◽

Establishment Method ◽

Alfalfa Seed ◽

Medicago Sativa L ◽

Companion Crop

In two experiments at Melfort using alfalfa (Medicago sativa L. ’Beaver’) seeded at a rate of 2 kg ha−1 with and without a Polish rapeseed (Brassica campestris L. ’Candle’) companion crop seeded at 5.5 kg ha−1, rapeseed yields in the establishment year were maximum when alfalfa and rapeseed were mixed and planted in 15-cm rows. Alfalfa showed no consistent seed yield differences between broadcast seeding, seeding in 15- or 61-cm rows, or seeding with or without the companion crop.Key words: Alfalfa, rapeseed, Brassica campestris, seed production

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Evaluation of GA4+7 plus 6-Benzyladenine as a Frost-rescue Treatment for Apple

HortTechnology ◽

10.21273/horttech.24.2.171 ◽

2014 ◽

Vol 24 (2) ◽

pp. 171-176 ◽

Cited By ~ 1

Author(s):

Steven McArtney ◽

Duane Greene ◽

Terence Robinson ◽

James Wargo

Keyword(s):

United States ◽

Minimum Temperature ◽

Fruit Set ◽

The United States ◽

Parthenocarpic Fruit ◽

Market Prices ◽

Fruit Number ◽

Rescue Treatment ◽

Production Areas ◽

Stimulation Of

Freeze events during bloom can be a relatively frequent occurrence in many apple (Malus ×domestica) production areas in the United States that significantly reduce orchard productivity and profitability. This study investigated the potential for a proprietary mixture of gibberellin A4 + A7 and 6-benzyladenine (GA4+7 plus 6-BA) to increase fruit set and cropping of apple following freeze events at three locations across the United States during bloom in 2012. GA4+7 plus 6-BA increased fruit set in two of five experiments, and increased fruit number and yield per tree in three of five experiments. GA4+7 plus 6-BA increased fruit set and yield of ‘Taylor Spur Rome’ following freezes on two consecutive days during bloom when the minimum temperature reached 23.9 and 28.4 °F. Fruit set was increased due to a stimulation of parthenocarpic fruit growth. Using locally obtained market prices, GA4+7 plus 6-BA treatments increased the crop value of ‘Taylor Spur Rome’, ‘Ginger Gold’, and ‘Jonagold’ by $3842, $977, and $6218 per acre, respectively. Although GA4+7 plus 6-BA application(s) after a freeze increased fruit set and cropping in some instances, tree yields were well below the average yields previously obtained in the test orchards.

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BETTERGRO BLACKEYE: A NEW PEST AND DISEASE RESISTANT HIGH YIELDING SOUTHERNPEA

HortScience ◽

10.21273/hortsci.27.11.1176g ◽

1992 ◽

Vol 27 (11) ◽

pp. 1176g-1176

Author(s):

R. L. Fery ◽

P. D. Dukes

Keyword(s):

United States ◽

Quality Evaluation ◽

Agricultural Research ◽

Insect Pest ◽

The United States ◽

United States Department ◽

Root Knot Nematode ◽

Department Of Agriculture ◽

Production Areas ◽

Agricultural Research Service

The Agricultural Research Service of the United States Department of Agriculture announced the release of `Bettergro Blackeye' southernpea on 24 July 1991. The new cultivar is well adapted for production throughout the southern United States where it can be expected to produce excellent yields of high quality, blackeye-type peas. `Bettergro Blackeye' outyielded the `Pinkeye Purple Hull-BVR' check in the 1986, 1987, 1988, and 1989 Regional Southernpea Cooperative Trials by 34.8, 14.3, 12.6, and 20.9%, respectively. Canned samples of fresh `Bettergro Blackeye' peas scored well in three years of quality evaluation tests. The new cultivar is resistant to the cowpea curculio, the major insect pest of the southernpea in southeastern production areas, and root knot, a severe root disease incited by several species of the root-knot nematode. `Bettergro Blackeye' plants have a greater tendency to produce a second crop than plants of most southernpea cultivars.

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Erratum: Characterization of Leaf Spot Pathogens from Several Spinach Production Areas in the United States

Plant Disease ◽

10.1094/pdis-11-19-2450.1-re ◽

2021 ◽

Vol 105 (3) ◽

pp. 719-719

Keyword(s):

United States ◽

Leaf Spot ◽

The United States ◽

Production Areas

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Diverse Responses of Lettuce Cultivars and Germplasm Lines to Infections of Three Isolates of Xanthomonas campestris pv. vitians

HortScience ◽

10.21273/hortsci.50.5.650 ◽

2015 ◽

Vol 50 (5) ◽

pp. 650-655 ◽

Cited By ~ 5

Author(s):

Yunwen Wang ◽

Huangjun Lu ◽

Richard N. Raid ◽

Gregg S. Nuessly ◽

Georgy Faroutine

Keyword(s):

United States ◽

Plant Resistance ◽

Host Plant Resistance ◽

Xanthomonas Campestris ◽

The United States ◽

Host Genotype ◽

Specific Host ◽

High Virulence ◽

Production Areas ◽

Leaf Lettuce

Bacterial leaf spot (BLS) disease, caused by Xanthomonas campestris pv. vitians (Xcv) has become an increasingly damaging disease in the lettuce production areas of the United States. To understand the nature of the outbreaks of this disease, the pathogenic variations for causing disease were evaluated on 29 lettuce cultivars and germplasm lines using three Xcv isolates recovered in different years from the Everglades Agriculture Area (EAA) of Florida. Significant differences were shown in both the BLS incidences and disease severities among the three Xcv isolates, and the rank from high virulence to less severity was L7 > JF196 > NF1. Our results suggest that the pathogenic variations of the isolates may have been associated with the epidemic outbreaks of BLS in EAA. Among the 29 lettuce genotypes, the host plant resistance was characterized by specific host genotype and Xcv isolate interactions. The leaf lettuce PI358001-1 was consistently in the high resistant category to all three Xcv isolates, and is a promising resistant source for development of resistant cultivars.

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Ceratobasidium Root Rot: A New Disease of Watermelon in Arizona

Plant Health Progress ◽

10.1094/php-2013-1125-01-br ◽

2013 ◽

Vol 14 (1) ◽

pp. 37

Author(s):

Claudia Nischwitz ◽

Periasamy Chitrampalam ◽

Mary Olsen

Keyword(s):

United States ◽

Root Rot ◽

Potential Problem ◽

The United States ◽

New Disease ◽

Production Areas

To our knowledge, Ceratobasidium species have never been previously reported as a pathogen of watermelon anywhere in the United States. Because of the recent reports in Italy and confirmed incidences in major watermelon production areas in Arizona, this disease should be recognized as a potential problem in watermelon. Accepted for publication 13 November 2013. Published 25 November 2013.

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