Onion ipmPIPE: A Coordinated Effort to Improve the Management of Onion Thrips and Iris yellow spot virus for the U.S. Onion Industry

2014 ◽  
Vol 15 (4) ◽  
pp. 172-183 ◽  
Author(s):  
Howard F. Schwartz ◽  
Diane Alston ◽  
Jeff Alwang ◽  
Michael Bartolo ◽  
Tamla Blunt ◽  
...  
Keyword(s):  
United States ◽  
Pest Management ◽  
The United States ◽  
Iris Yellow Spot Virus ◽  
Plant Diseases ◽  
Yellow Spot ◽  
Onion Thrips ◽  
Spot Virus ◽  
Transmitted Virus ◽  
The U.S

Onion (Allium cepa) is an economically important vegetable crop in the United States, generating nearly $900 million annually in farm receipts. Pests such as onion thrips (Thrips tabaci) and a thrips-transmitted virus disease, Iris yellow spot (IYS), caused by Iris yellow spot virus (IYSV), have emerged in recent years as high priority, invasive, or potential threats to sustainable onion production throughout the United States and the world. The long-term goal of a recent United States Department of Agriculture (USDA)-National Institute of Food and Agriculture (NIFA)-Specialty Crop Research Initiative (SCRI) funded project was to optimize sound pest management decision making in onion through the development and deployment of a sustainable online information management platform called the Onion ipmPIPE (Onion integrated pest management Pest Information Platform for Extension and Education). Project participants in seven states generated an average of 500 reports annually on the occurrence of 20 priority insect pests and plant diseases, and enhanced the timeliness and effectiveness of IPM strategies implemented by the growers and industry locally and regionally in response to these reports. Thrips populations are generally greatest at all locations during July and August of each year, which compounds plant responses to environmental stresses such as temperature and limited or lower quality (e.g., saline) irrigation water. The increase in numbers of thrips (majority being T. tabaci) also aggravates problems with the onion thrips-transmitted virus IYSV (mentioned above) and IYS, which generally increases in incidence and severity during this same period. A comprehensive website (http//:www.alliumnet.com/IPMPipe.html) and educational materials (bulletin, diagnostic cards, videos) were developed in response to the insect and disease threats, and have been shared with onion stakeholders throughout the United States and elsewhere. The project is also developing risk assessment models, a smartphone app, onion growing-degree-day review for efficacy of the current model based on 5.5°C from planting, and enhanced pathogen diagnostic tools for future testing and validation by onion stakeholders. Visiting the Onion ipmPIPE website was estimated by respondents to increase onion yields by 280 kg/hectare and reduce pesticide costs by $910/hectare on average. The Onion ipmPIPE platform is scale neutral, and supports a range of organic and conventional growers producing onions on small plots to large-scale commercial fields. Increased participation of stakeholders, including consumers, in a national educational project such as Onion ipmPIPE will better serve current and future interests in sustainability and profitability of critical food crops for the U.S. marketplace. Accepted 25 September 2014. Published 12 November 2014.

scholarly journals First Report of Iris yellow spot virus on Onion in New York

Plant Disease ◽  
2007 ◽  
Vol 91 (3) ◽  
pp. 327-327 ◽  
Author(s):  
C. A. Hoepting ◽  
H. F. Schwartz ◽  
H. R. Pappu
Keyword(s):  
United States ◽  
New York ◽  
Iris Yellow Spot Virus ◽  
Yellow Spot ◽  
N Gene ◽  
Nucleotide Sequence Analysis ◽  
Rt Pcr ◽  
Onion Thrips ◽  
Spot Virus ◽  
First Report

Iris yellow spot virus (IYSV [family Bunyaviridae, genus Tospovirus]), a potentially devastating disease of onion vectored by onion thrips (Thrips tabaci Lindeman), has been reported from most states in the western United States where significant onion production occurs, with the most recent report from Texas (1). In June 2006, volunteer onion (Allium cepa) plants in Orleans County, New York (Elba muckland) were found to have symptoms indicative of IYSV infection. The scapes (seed stalks) of the volunteer onions found at the edge of a cull pile from a 2005 onion crop exhibited diamond-shaped lesions, each with a distinct green center and a double yellow border. Approximately 25 of 100 plants of red and yellow onion cultivars exhibited characteristic IYSV lesions. The cull pile was composed primarily of locally grown onions, although a few of the bulbs were grown from imported bare-root transplants imported from Arizona. Symptomatic plants tested positive for IYSV using IYSV-specific antiserum from Agdia Inc. (Elkhart, IN) in a double-antibody sandwich-ELISA. The presence of IYSV was verified by reverse transcription (RT)-PCR using primers derived from the small RNA of IYSV (S-RNA). The primers flanked the IYSV nucleocapsid (N) gene (5′-TAA AAC AAA CAT TCA AAC AA-3′ and 5′-CTC TTA AAC ACA TTT AAC AAG CAC-3′ (3). RT-PCR assays produced a PCR amplicon of expected size (approximately 1.2 kb) and the product was cloned and sequenced. Nucleotide sequence analysis confirmed the identity of the amplicon as that of the IYSV S-RNA. Sequence comparisons showed 95 to 98% identity with known IYSV N gene sequences available in GenBank. The virus is poorly transmitted to onion by mechanical inoculation and we did not have access to a noninfested colony of the onion thrips vector to transfer the virus from these samples to noninfected onions. No asymptomatic plants were tested. Among the onion-growing states in the eastern United States, IYSV has previously only been reported from Georgia (2). To our knowledge, this is the first report of IYSV in New York and the greater northeastern United States. The finding of this disease in New York confirms further spread of the virus within North America and the need for research to develop more effective management options to reduce the impact of IYSV on onion crops. References: (1) M. Miller et al. Plant Dis. 90:1359, 2006. (2) S. W. Mullis et al. Plant Dis. 90:377, 2006. (3) H. R. Pappu et al. Arch. Virol. 151:1015, 2006.

scholarly journals First Report of Iris yellow spot virus in Commercial Leek (Allium porrum) in the United States

Plant Disease ◽  
2007 ◽  
Vol 91 (1) ◽  
pp. 113-113 ◽  
Author(s):  
H. F. Schwartz ◽  
K. Otto ◽  
H. R. Pappu
Keyword(s):  
United States ◽  
The United States ◽  
Iris Yellow Spot Virus ◽  
Yellow Spot ◽  
N Gene ◽  
Allium Porrum ◽  
Rt Pcr ◽  
Spot Virus ◽  
Disease Symptoms ◽  
First Report

Iris yellow spot virus (IYSV; family Bunyaviridae, genus Tospovirus) has a wide host range, with onion (Allium cepa L.) being one of the most economically important hosts. IYSV has been widely reported from this species throughout most onion-production regions of the United States and many areas of the world in recent years. A relative of onion, leek (Allium porrum L.), has been reported to be a host of IYSV in countries such as the Netherlands, Reunion Island, and Australia (1,4). A related tospovirus, Tomato spotted wilt virus (TSWV), was recently reported causing necrotic lesions and extended bleaching of leaf tips of leek in Georgia (2). In September of 2006, disease symptoms suspected to be caused by IYSV were observed on central and outer leaves of plants in a 2.6-ha section of commercial leeks being grown from seed (cvs. Tadorna and King Richard). The leek plants were adjacent to a 3.1-ha section of seeded onion (cv. Exacta) that had been harvested 2 weeks earlier. Twenty-five to thirty percent of unharvested onion plants next to the leek section also exhibited IYSV-type disease symptoms generally on the central leaves. Both Allium spp. were seeded 5 months earlier and grown under certified organic, pivot-irrigated conditions in Larimer County in northern Colorado. Disease symptoms on leek and onion leaves appeared as dry, white-to-straw-colored, spindle- or diamond-shaped lesions that ranged in size from 5 to 10 × 25 to 50 mm or larger depending on lesion age. Lesion centers, especially on leek, often had green centers with concentric rings of alternating green and straw-colored tissue. Green tissue near necrotic lesions of a single symptomatic leaf from 10 plants each of leek and onion was sampled and analyzed using a double-antibody sandwich (DAS)-ELISA (Agdia, Inc., Elkhart, IN). Five of ten leek and nine of ten onion samples were positive for IYSV. Using reverse transcription (RT)-PCR and primers specific to the small RNA of IYSV (5′-TAA AAC AAA CAT TCA AAC AA-3′ and 5′-CTC TTA AAC ACA TTT AAC AAG CAC-3′), the complete nucleocapsid (N) gene was amplified from symptomatic leek plants and then sequenced (3). Comparisons with IYSV N gene sequences available in the GenBank confirmed the identity of the virus as IYSV. Leek samples were negative for TSWV when tested by RT-PCR with TSWV-specific primers. In addition, three specimens of the presumed thrips vector recovered from five IYSV-infected leek plants were identified as Thrips tabaci (L. A. Mahaffey and W. S. Cranshaw, personal communication). Earlier in the season, T. tabaci was observed in the nearby planting of onion that also exhibited IYSV in September. To our knowledge, this is the first report of natural infection of commercial leek with IYSV in the United States. The incidence of plants (25 to 30%) with foliar lesions on multiple leaves and stunting of 5% of infected plants in both leek cultivars suggests that IYSV could seriously reduce leek stem development and marketability. References: (1) I. Cortes et al. Phytopathology 88:1276, 1998. (2) C. Nischwitz et al. Plant Dis. 90:525, 2006. (3) H. R. Pappu et al. Arch. Virol. 151:1015, 2006. (4) T. N. Smith et al. Plant Dis. 90:729, 2006.

scholarly journals First Report of Natural Infection of Garlic with Iris yellow spot virus in the United States

Plant Disease ◽  
2009 ◽  
Vol 93 (8) ◽  
pp. 839-839 ◽  
Author(s):  
S. Bag ◽  
P. Rogers ◽  
R. Watson ◽  
H. R. Pappu
Keyword(s):  
United States ◽  
Natural Infection ◽  
Sandwich Elisa ◽  
The United States ◽  
Iris Yellow Spot Virus ◽  
Yellow Spot ◽  
N Gene ◽  
Spot Virus ◽  
Sequence Comparisons ◽  
First Report

Iris yellow spot virus (IYSV; family Bunyaviridae, genus Tospovirus) is an important constraint to onion bulb and seed production in several onion-growing regions of the United States (1,3). While garlic (Allium sativum) was reported to be infected with IYSV in Réunion Island (4), there have been no confirmed reports of natural infection of garlic in the United States. Garlic plants showing near-diamond-shaped lesions were found in August of 2008 in Marion County, Oregon. The 0.4046-ha (1-acre) field plot consisted of various true-seeded garlic varieties and was adjacent to three onion fields that showed IYSV symptoms. Symptoms were observed on 5% of the garlic plants with most of the symptomatic plants displaying small and diffuse straw-colored spots. Seven of these symptomatic plants were selected for testing. Of these, two showed characteristic diamond-shaped, elongated, straw-colored lesions on garlic scapes. However, the lesions were more diffuse with less-defined edges compared with the characteristic diamond-shaped lesions that are often associated with IYSV infection (1). All symptomatic plants were positive for IYSV by double-antibody sandwich-ELISA with a commercially available kit (Agdia Inc., Elkhart, IN). To verify IYSV infection, total nucleic acid extracts from the symptomatic parts of the leaves were prepared and tested for the presence of IYSV by reverse transcription (RT)-PCR with primers 5′-TAAAACAAACATTCAAACAA-3′ and 5′-CTCTTAAACACATTTAACAAGCAC-3′, which flank the nucleocapsid (N) gene coded by the small RNA of IYSV (2). An approximate 1.1-kb amplicon was obtained from all symptomatic plants and cloned and sequenced. Nucleotide sequence comparisons using BLAST showed that a consensus of three clones derived from the amplicon from garlic (No. FJ514257) was 85 to 99% identical with IYSV sequences available in GenBank (Nos. AF001387, AB180918, and AB286063), confirming the identity of IYSV. To our knowledge, this is the first report of natural infection of IYSV infection of garlic in the United States. Additional surveys and testing are needed to obtain a better understanding of IYSV incidence in garlic to evaluate its impact on garlic production. References: (1) D. Gent et al. Plant Dis. 90:1468, 2006. (2) H. R. Pappu et al. Arch. Virol. 151:1015, 2006. (3) H. R. Pappu et al. Virus Res. 141:219, 2009. (4) I. Robène-Soustrade et al. Plant Pathol. 55:288, 2006.

scholarly journals Outbreak of Iris yellow spot virus in Onion Seed Crops in Central Oregon

Plant Disease ◽  
2005 ◽  
Vol 89 (1) ◽  
pp. 105-105 ◽  
Author(s):  
F. J. Crowe ◽  
H. R. Pappu
Keyword(s):  
United States ◽  
The United States ◽  
Iris Yellow Spot Virus ◽  
Yellow Spot ◽  
N Gene ◽  
Rt Pcr ◽  
Spot Virus ◽  
Seed Crop ◽  
Onion Seed ◽  
Seed Crops

Iris yellow spot virus (IYSV) of the genus Tospovirus, family Bunyaviridae is considered an emerging or reemerging pathogen affecting onions in the United States. The virus has been endemic to the Treasure Valley of southern Idaho for more than a decade (4). Reports of its further spread came from several states in the region, most recently from New Mexico and Washington (1,3). During the 2004 growing season, a few onion seed crops near Madras (Jefferson County) in central Oregon showed symptoms suggestive of IYSV infection, including characteristic diamond-shaped scape lesions (2). By July, scapes in one-half of a 4-ha field were 100% symptomatic and 95% lodged, leading to nearly total crop failure; in the other half, scapes were 30 to 40% symptomatic and 15% lodged, with symptoms and lodging increasing weekly at 8 weeks before harvest. The half of this crop with greater incidence was immediately adjacent to a field where very limited IYSV-like symptoms were noticed in a 2002–2003 onion seed crop that was harvested in mid-August 2003, after the highly symptomatic 2003–2004 onion seed crop was planted next to it in early July 2003. Both crops were planted from true seed. In another onion seed crop located 1,000 m away, IYSV-like symptoms were abundant around the field edges in July and through the field in August 2004, with approximately 5% lodging by mid-August. A small number of plants with IYSV-like symptoms were present in a few more distant fields, but not in most onion seed fields in central Oregon. Symptomatic plants were collected and tested in the laboratory for confirmation of IYSV infection. IYSV was confirmed using enzyme-linked immunosorbent assay (ELISA) with a commercially available antiserum (Agdia Inc., Elkhart, IN). Total nucleic acids were extracted, and using primers specific to the nucleocapsid (N) gene of IYSV (3), reverse transcription-polymerase chain reaction (RT-PCR) was done. RT-PCR gave DNA amplicons of the expected size. The DNA amplicons were cloned and sequenced. Nucleotide sequence comparisons with known IYSV N gene sequences confirmed virus identity. The rapid spread of IYSV in the Pacific Northwest and its severity of incidence often leading to 100% incidence is a cause for concern for onion growers and industry. Efforts to identify management practices to reduce its impact have to be undertaken on a regional basis because of its widespread occurrence across several states in the northwestern United States. References: (1) R. Creamer et al. Plant Dis. 88:1049, 2004 (2) L. J. du Toit et al. APSnet image of the week. On-line publication: http://apsnet.org/online/archive/ 2003/IW000030.asp , 2003. (3) L. J. du Toit et al. Plant Dis. 88:222, 2004. (4) J. M. Hall et al. Plant Dis. 77:952, 1993.

scholarly journals First Report of Iris yellow spot virus on Onion (Allium cepa) in Texas

Plant Disease ◽  
2006 ◽  
Vol 90 (10) ◽  
pp. 1359-1359 ◽  
Author(s):  
M. E. Miller ◽  
R. R. Saldana ◽  
M. C. Black ◽  
H. R. Pappu
Keyword(s):  
Disease Incidence ◽  
Iris Yellow Spot Virus ◽  
Yellow Spot ◽  
N Gene ◽  
Nucleotide Sequence Analysis ◽  
Rt Pcr ◽  
Onion Thrips ◽  
Spot Virus ◽  
Das Elisa ◽  
Bulb Yield

Iris yellow spot virus (IYSV; family Bunyaviridae, genus Tospovirus) has emerged as a potentially devastating and widespread virus of onion. IYSV was first reported in the United States from Idaho in 1993 and has since spread to many of the onion-producing areas (1). In South America, the most recent reports of the virus on onion were from Peru and Chile (2,4). In 2005, onion plants in Uvalde County, Texas exhibited necrotic lesions on leaves typical of IYSV and disease incidence approached 100% in some fields with yield loss and quality problems. Five of six plants tested were positive for IYSV with double antibody sandwich-enzyme linked immunosorbent assay (DAS-ELISA; Agdia Inc., Elkhart, IN). In 2006, similar lesions were observed on onion plants in Uvalde County and approximately 400 km south in Hidalgo and Cameron counties. Infection points generally started as a single plant near the edge of fields and spread to plants in a 3- to 4-m area after 1 to 2 weeks. Early-season disease incidence was low in onions grown for bulbs and transplants, <10% in 2006. Disease incidence increased in some fields until the crop was harvested. Leaves of symptomatic plants were tested for IYSV and Tomato spotted wilt virus (TSWV) using DAS-ELISA, and 18 of 23 samples from the Hidalgo County area and 12 of 21 samples from the Uvalde County area were positive for IYSV. All samples tested for TSWV from these counties were negative. Virus infection in some ELISA-positive plants was verified by reverse transcription-polymerase chain reaction (RT-PCR) using primers derived from the small RNA of IYSV. The primers flanked the IYSV nucleocapsid (N) gene (5′-TAA AAC AAA CAT TCA AAC AA-3′ and 5′-CTC TTA AAC ACA TTT AAC AAG CAC-3′ (3). RT-PCR gave a PCR product of expected size (approximately 1.2 kb). The DNA amplicon was cloned and sequenced (GenBank Accession No. DQ658242). Nucleotide sequence analysis confirmed the identity of the amplicon as that of IYSV N gene and sequence comparisons with known IYSV N gene sequences showed 95 to 98% sequence identity. The primary vector of IYSV, onion thrips (Thrips tabaci), is a widespread and destructive pest of onion in south Texas. The year-to-year incidence of IYSV and the severity of the disease will probably depend on the onion thrips population levels. Bulb yield reduction could be severe during years with high thrips populations. More research is needed to determine the impact of IYSV on bulb yield in Texas, the relationship between IYSV incidence and T. tabaci population levels, and oversummering hosts. To our knowledge, this is the first known report of IYSV in Texas. References: (1) D. H. Gent et al. Plant Dis. 88:446, 2004, (2) S. W. Mullis et al. Plant Dis. 90:377, 2006, (3) H. Pappu et al. Arch. Virol. 151:1015, 2006. (4) M. Rosales et al. Plant Dis. 89:1245, 2005.

scholarly journals First Report of Iris yellow spot virus on Onion and Leek in Western Oregon

Plant Disease ◽  
2007 ◽  
Vol 91 (4) ◽  
pp. 468-468 ◽  
Author(s):  
D. H. Gent ◽  
R. R. Martin ◽  
C. M. Ocamb
Keyword(s):  
United States ◽  
Disease Incidence ◽  
The United States ◽  
Yellow Spot ◽  
Onion Bulb ◽  
Spot Virus ◽  
First Report ◽  
Seed Crop ◽  
Onion Seed ◽  
Seed Crops

Onion (Allium cepa) and leek (Allium porrum) are grown on approximately 600 ha in western Oregon annually for bulb and seed production. During July and August of 2006, surveys of onion bulb crops and onion and leek seed crops in western Oregon found plants with symptoms of elongated to diamond-shaped, straw-colored lesions characteristic of those caused by Iris yellow spot virus (IYSV) (1–4). Symptomatic plants were collected from fields of an onion bulb crop, an onion seed crop, and two leek seed crops located in Marion County. The onion bulb crop had been planted in the spring of 2006, and the onion and leek seed crops had been planted in the fall of 2005, all direct seeded. Cultivar names were not provided for proprietary purposes. Symptomatic plants in the onion bulb crop and leek seed crop generally were found near the borders of the field. Disease incidence was less than 5% and yield losses in these crops appeared to be negligible. In the onion seed crop, symptomatic plants were found throughout the field and disease incidence was approximately 20%. Approximately 1% of the onion plants in this field had large necrotic lesions that caused the seed stalks (scapes) to lodge. The presence of IYSV was confirmed from symptomatic leaves and scapes by ELISA (Agdia Inc., Elkhart, IN) using antiserum specific to IYSV. RNA was extracted from symptomatic areas of onion leaves and scapes, and a portion of the nucleocapsid gene was amplified by reverse transcription-PCR. The amplicons were sequenced and found to share more than 99% nucleotide and amino acid sequence identity with an onion isolate of IYSV from the Imperial Valley of California (GenBank Accession No. DQ233475). In the Pacific Northwest region of the United States, IYSV has been confirmed in the semi-arid regions of central Oregon (1), central Washington (2), and the Treasure Valley of eastern Oregon and southwest Idaho (3). To our knowledge, this is the first report of the disease on a host crop in the mild, maritime region west of the Cascade Mountain Range and the first report of IYSV on leek seed crops in the United States, which complements a simultaneous report of IYSV on commercial leek in Colorado. The presence of IYSV may have implications for the iris and other ornamental bulb industries in western Oregon and western Washington. This report underscores the need for further research to determine the impact of the disease on allium crops and other hosts and the development of effective management programs for IYSV and the vector, Thrips tabaci. References: (1) F. J. Crowe and H. R. Pappu. Plant Dis. 89:105, 2005. (2) L. J. du Toit et al. Plant Dis. 88:222, 2004. (3) J. M. Hall et al. Plant Dis. 77:952, 1993. (4) H. F. Schwartz et al. Plant Dis. 91:113, 2007.

scholarly journals Spatial and Temporal Distribution of Iris yellow spot virus and Thrips in Colorado Onion Fields

2010 ◽  
Vol 11 (1) ◽  
pp. 11 ◽  
Author(s):  
Howard F. Schwartz ◽  
David H. Gent ◽  
Scott M. Fichtner ◽  
Rajiv Khosla ◽  
Linda A. Mahaffey ◽  
...  
Keyword(s):  
Soil Ph ◽  
Management Practices ◽  
Disease Incidence ◽  
Risk Index ◽  
Iris Yellow Spot Virus ◽  
Yellow Spot ◽  
Onion Thrips ◽  
Spot Virus ◽  
Negatively Associated ◽  
Sodium Percent

Iris yellow spot virus and its onion thrips vector (Thrips tabaci) are yield limiting pests of onion in the western United States. This two-year project investigated the relationship of iris yellow spot to thrips populations, soil properties, and grower management practices in six onion fields during 2005 and 2006 in Colorado. Thrips density (average number of thrips per plant per day) was negatively associated with soil pH (r = -0.61). The incidence of iris yellow spot at harvest was positively associated with organic matter, zinc, potassium, percent sodium, percent hydrogen, copper, iron, and soil pH. Thrips-days had a clear non-linear association with disease incidence at harvest. Onion plant population was positively associated with levels of iron, phosphorus, potassium, and zinc; and negatively associated with calcium, salts, percent potassium, and cation exchange capacity (CEC). Marketable (medium or larger sized bulbs) yield was negatively associated with phosphorus and percent potassium, and positively associated with salts, calcium, and CEC. Results from this project could contribute to the development of a risk index to predict potential risk from Iris yellow spot virus and its onion thrips vector. Accepted for publication 6 July 2010. Published 20 August 2010.

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