@article{quesada-ocampo_butler_withers_ivors_2014, title={First Report of Fusarium Rot of Garlic Bulbs Caused by Fusarium proliferatum in North Carolina}, volume={98}, ISSN={["1943-7692"]}, DOI={10.1094/pdis-01-14-0040-pdn}, abstractNote={In August of 2013, garlic bulbs (Allium sativum) of the variety Chesnok Red grown and stored under dry conditions by a commercial producer in Buncombe County showed water-soaked, tan to salmon-pink lesions. Lesions on cloves became soft over time, slightly sunken, and had mycelium near the center of the bulb, which is characteristic of Fusarium rots on garlic (1,2). Approximately 10 to 20% of the bulbs inspected in the drying storage room were affected. Surface-sterilized tissue was excised from the margin of lesions on eight bulbs, plated onto acid potato dextrose agar (APDA), and incubated in the dark at room temperature (21°C). White to light pink colonies with abundant aerial mycelium and a purple pigment were obtained from all samples after 2 to 3 days of incubation. Inspection of colony morphology and reproductive structures under a microscope revealed that isolate characteristics were consistent with Fusarium proliferatum (Matsushima) Nirenberg. Microscopic morphological characteristics of the isolate included hyaline, septate hyphae; slender, slightly curved macroconidia with three to five septae produced in sporodochia; curved apical cell; and club-shaped, aseptate microconidia (measuring 3.3 to 8.3 × 1.1 to 1.3 μm) produced in chains by mono and polyphyalides. To further define the identity of the isolate, the beta-tubulin (Btub), elongation factor 1a (EF1a), and internal transcribed spacer (ITS) regions were amplified and sequenced (3). The resulting sequences were compared against the GenBank nucleotide database by using a BLAST alignment, which revealed that the isolate had 100% identity with F. proliferatum for the Btub, EF1a, and ITS regions (GenBank Accession Nos. AF291055.1, JX118976.1, and HF930594.1, respectively). Sequences for the isolate were deposited in GenBank under accessions KJ128963, KJ128964, and KJ128965. While there have been other reports of F. proliferatum causing bulb rot of garlic in the United States (1), to our knowledge, this is the first report in North Carolina. The finding is significant since F. proliferatum can produce a broad range of mycotoxins, including fumonisins, when infecting its host, which is a concern for food safety in Allium crops. References: (1) F. M. Dugan et al. Plant Pathol. 52:426, 2003. (2) L. J. du Toit and F. M. Dugan. Page 15 in: Compendium of Onion and Garlic Diseases and Pests. H. F. Schwartz and S. K. Mohan, eds. The American Phytopathological Society, St. Paul, MN, 2008. (3) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, San Diego, CA, 1990.}, number={7}, journal={PLANT DISEASE}, publisher={Scientific Societies}, author={Quesada-Ocampo, L. M. and Butler, S. and Withers, S. and Ivors, K.}, year={2014}, month={Jul}, pages={1009–1010} }
 @article{wallace_adams_ivors_ojiambo_quesada-ocampo_2014, title={First Report of Pseudoperonospora cubensis Causing Downy Mildew on Momordica balsamina and M. charantia in North Carolina}, volume={98}, ISSN={["1943-7692"]}, url={http://europepmc.org/abstract/med/30699625}, DOI={10.1094/pdis-03-14-0305-pdn}, abstractNote={Momordica balsamina (balsam apple) and M. charantia L. (bitter melon/bitter gourd/balsam pear) commonly grow in the wild in Africa and Asia; bitter melon is also cultivated for food and medicinal purposes in Asia (1). In the United States, these cucurbits grow as weeds or ornamentals. Both species are found in southern states and bitter melon is also found in Pennsylvania and Connecticut (3). Cucurbit downy mildew (CDM), caused by the oomycete Pseudoperonospora cubensis, was observed on bitter melon and balsam apple between August and October of 2013 in six North Carolina sentinel plots belonging to the CDM ipmPIPE program (2). Plots were located at research stations in Johnston, Sampson, Lenoir, Henderson, Rowan, and Haywood counties, and contained six different commercial cucurbit species including cucumbers, melons, and squashes in addition to the Momordica spp. Leaves with symptoms typical of CDM were collected from the Momordica spp. and symptoms varied from irregular chlorotic lesions to circular lesions with chlorotic halos on the adaxial leaf surface. Sporulation on the abaxial side of the leaves was observed and a compound microscope revealed sporangiophores (180 to 200 μm height) bearing lemon-shaped, dark sporangia (20 to 35 × 10 to 20 μm diameter) with papilla on one end. Genomic DNA was extracted from lesions and regions of the NADH dehydrogynase subunit 1 (Nad1), NADH dehydrogynase subunit 5 (Nad5), and internal transcribed spacer (ITS) ribosomal RNA genes were amplified and sequenced (4). BLAST analysis revealed 100% identity to P. cubensis Nad1 (HQ636552.1, HQ636551.1), Nad5 (HQ636556.1), and ITS (HQ636491.1) sequences in GenBank. Sequences from a downy mildew isolate from each Momordica spp. were deposited in GenBank as accession nos. KJ496339 through 44. To further confirm host susceptibility, vein junctions on the abaxial leaf surface of five detached leaves of lab-grown balsam apple and bitter melon were either inoculated with a sporangia suspension (10 μl, 104 sporangia/ml) of a P. cubensis isolate from Cucumis sativus ('Vlaspik' cucumber), or with water as a control. Inoculated leaves were placed in humidity chambers to promote infection and incubated using a 12-h light (21°C) and dark (18°C) cycle. Seven days post inoculation, CDM symptoms and sporulation were observed on inoculated balsam apple and bitter melon leaves. P. cubensis has been reported as a pathogen of both hosts in Iowa (5). To our knowledge, this is the first report of P. cubensis infecting these Momordica spp. in NC in the field. Identifying these Momordica spp. as hosts for P. cubensis is important since these cucurbits may serve as a source of CDM inoculum and potentially an overwintering mechanism for P. cubensis. Further research is needed to establish the role of non-commercial cucurbits in the yearly CDM epidemic, which will aid the efforts of the CDM ipmPIPE to predict disease outbreaks. References: (1) L. K. Bharathi and K. J. John. Momordica Genus in Asia-An Overview. Springer, New Delhi, India, 2013. (2) P. S. Ojiambo et al. Plant Health Prog. doi:10.1094/PHP-2011-0411-01-RV, 2011. (3) PLANTS Database. Natural Resources Conservation Service, USDA. Retrieved from http://plants.usda.gov/ , 7 February 2014. (4) L. M. Quesada-Ocampo et al. Plant Dis. 96:1459, 2012. (5) USDA. Index of Plant Disease in the United States. Agricultural Handbook 165, 1960.}, number={9}, journal={PLANT DISEASE}, publisher={Scientific Societies}, author={Wallace, E. and Adams, M. and Ivors, K. and Ojiambo, P. S. and Quesada-Ocampo, L. M.}, year={2014}, month={Sep}, pages={1279–1279} }
 @article{loyd_benson_ivors_2014, title={Phytophthora Populations in Nursery Irrigation Water in Relationship to Pathogenicity and Infection Frequency of Rhododendron and Pieris}, volume={98}, ISSN={["1943-7692"]}, DOI={10.1094/pdis-11-13-1157-re}, abstractNote={Phytophthora spp. are waterborne plant pathogens that are commonly found in streams, rivers, and reclaimed irrigation water. Rhododendron and Pieris trap plants at two commercial nurseries were irrigated with water naturally infested with Phytophthora spp. during the 2011 and 2012 growing seasons to assess the frequency of disease. Phytophthora spp. were consistently recovered from water samples at every collection time but detected on only 2 of the 384 trap plants during the two growing seasons. Pathogenicity assays proved that Phytophthora hydropathica and Phytophthora taxon PgChlamydo, commonly recovered taxa in irrigation water at the nurseries, were foliar pathogens of Rhododendron and Pieris; however, neither species was able to cause root rot on these same hosts. Overall, Phytophthora spp.-infested irrigation water did not act as a primary source of infection on Rhododendron and Pieris, even though foliar pathogenic species of Phytophthora were present in the water.}, number={9}, journal={PLANT DISEASE}, author={Loyd, A. L. and Benson, D. M. and Ivors, K. L.}, year={2014}, month={Sep}, pages={1213–1220} }
 @article{olson_jeffers_ivors_steddom_williams-woodward_mmbaga_benson_hong_2013, title={Diversity and mefenoxam sensitivity of Phytophthora spp. associated with the ornamental horticulture industry in the Southeastern United States}, volume={97}, number={1}, journal={Plant Disease}, author={Olson, H. A. and Jeffers, S. N. and Ivors, K. L. and Steddom, K. C. and Williams-Woodward, J. L. and Mmbaga, M. T. and Benson, D. M. and Hong, C. X.}, year={2013}, pages={86–92} }
 @inproceedings{ganci_benson_ivors_2013, title={Susceptibility of commercial boxwood taxa to Cylindrocladium buxicola (c)}, volume={1014}, DOI={10.17660/actahortic.2013.1014.83}, booktitle={Proceedings of the international plant propagators' society}, author={Ganci, M. and Benson, D. M. and Ivors, K. L.}, year={2013}, pages={369–370} }
 @article{henricot_david_ivors_heungens_spooner_sierra_daughtrey_2012, title={(2085) Proposal to conserve the name Cylindrocladium buxicola against C. pseudonaviculatum (Ascomycota)}, volume={61}, number={5}, journal={Taxon}, author={Henricot, B. and David, J. and Ivors, K. and Heungens, K. and Spooner, B. and Sierra, A. P. and Daughtrey, M. L.}, year={2012}, pages={1119–1120} }
 @article{everts_osborne_gevens_vasquez_gugino_ivors_harmon_2012, title={Extension plant pathology: Strengthening resources to continue serving the public interest}, volume={102}, number={7}, journal={Phytopathology}, author={Everts, K. L. and Osborne, L. and Gevens, A. J. and Vasquez, S. J. and Gugino, B. K. and Ivors, K. and Harmon, C.}, year={2012}, pages={652–655} }
 @article{hu_perez_donahoo_mcleod_myers_ivors_secor_roberts_deahl_fry_et al._2012, title={Recent Genotypes of Phytophthora infestans in the Eastern United States Reveal Clonal Populations and Reappearance of Mefenoxam Sensitivity}, volume={96}, ISSN={["1943-7692"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84866163472&partnerID=MN8TOARS}, DOI={10.1094/pdis-03-11-0156-re}, abstractNote={Isolates of Phytophthora infestans (n = 178) were collected in 2002 to 2009 from the eastern United States, Midwestern United States, and eastern Canada. Multilocus genotypes were defined using allozyme genotyping, and DNA fingerprinting with the RG-57 probe. Several previously described and three new mulitilocus genotypes were detected. The US-8 genotype was found commonly on commercial potato crops but not on tomato. US-20 was found on tomato in North Carolina from 2002 through 2007 and in Florida in 2005. US-21 was found on tomato in North Carolina in 2005 and Florida in 2006 and 2007. US-22 was detected on tomato in 2007 in Tennessee and New York and became widespread in 2009. US-22 was found in 12 states on tomato and potato and was spread on tomato transplants. This genotype accounted for about 60% of all the isolates genotyped. The US-23 genotype was found in Maryland, Virginia, Pennsylvania, and Delaware on both tomato and potato in 2009. The US-24 genotype was found only in North Dakota in 2009. A1 and A2 mating types were found in close proximity on potato and tomato crops in Pennsylvania and Virginia; therefore, the possibility of sexual reproduction should be monitored. Whereas most individuals of US-8 and US-20 were resistant to mefenoxam, US-21 appeared to be intermediately sensitive, and isolates of US-22, US-23, and US-24 were largely sensitive to mefenoxam. On the basis of sequence analysis of the ras gene, these latter three genotypes appear to have been derived from a common ancestor. Further field and laboratory studies are underway using simple sequence repeat genotyping to monitor current changes in the population structure of P. infestans causing late blight in North America.}, number={9}, journal={PLANT DISEASE}, author={Hu, Chia-Hui and Perez, Frances G. and Donahoo, Ryan and McLeod, Adele and Myers, Kevin and Ivors, Kelly and Secor, Gary and Roberts, Pamela D. and Deahl, Kenneth L. and Fry, William E. and et al.}, year={2012}, month={Sep}, pages={1323–1330} }
 @article{richter_benson_ivors_2011, title={Microbial Profiling of Cultural Systems for Suppression of Phytophthora Root Rot in Fraser Fir}, volume={95}, ISSN={["1943-7692"]}, DOI={10.1094/pdis-03-10-0238}, abstractNote={Phytophthora root rot of Fraser fir, caused by several Phytophthora spp., is a severe problem in Christmas tree production. Since fungicides are not economically viable for disease management in field plantings and host resistance is not available, cultural control methods were investigated. Mulches, dairy compost, and soil pH adjustment were tested at five field sites in North Carolina. Treatments included wood chips, wood chips plus compost, or pine bark as raised beds, and compost or sulfur tilled into soil. Soil and mulch microbial populations were characterized by dilution plating and calculation of a log series diversity index, and by enzyme analyses at 5, 12, 17, and 24 months after planting. Bacterial and fungal counts, microbial activity, and cellulase activity were higher in mulch than in soil at all sites and times (P < 0.01), and generally did not differ among mulch types or among soils. Treatments significantly affected disease ratings and tree survival at three of five sites, with one or more mulch treatments yielding lower disease ratings and greater survival than controls. Tree mortality at each time point varied significantly with cellulase activity in the upper root zone (P = 0.005). Other biological variables did not show significant relationships with disease ratings or mortality.}, number={5}, journal={PLANT DISEASE}, author={Richter, B. S. and Benson, D. M. and Ivors, K. L.}, year={2011}, month={May}, pages={537–546} }
 @article{abad_ivors_gallup_abad_shew_2011, title={Morphological and molecular characterization of Phytophthora glovera sp nov from tobacco in Brazil}, volume={103}, number={2}, journal={Mycologia}, author={Abad, Z. G. and Ivors, K. L. and Gallup, C. A. and Abad, J. A. and Shew, H. D.}, year={2011}, pages={341–350} }
 @article{bartz_cubeta_toda_naito_ivors_2010, title={An In planta method for assessing the role of basidiospores in Rhizoctonia foliar disease of Tomato}, volume={94}, number={5}, journal={Plant Disease}, author={Bartz, F. E. and Cubeta, M. A. and Toda, T. and Naito, S. and Ivors, K. L.}, year={2010}, pages={515–520} }
 @article{kang_mansfield_park_geiser_ivors_coffey_grunwald_martin_levesque_blair_2010, title={The Promise and pitfalls of sequence-based identification of plant-pathogenic fungi and oomycetes}, volume={100}, number={8}, journal={Phytopathology}, author={Kang, S. and Mansfield, M. A. and Park, B. and Geiser, D. M. and Ivors, K. L. and Coffey, M. D. and Grunwald, N. J. and Martin, F. N. and Levesque, C. A. and Blair, J. E.}, year={2010}, pages={732–737} }
 @article{gruenwald_goss_ivors_garbelotto_martin_prospero_hansen_bonants_hamelin_chastagner_et al._2009, title={Standardizing the Nomenclature for Clonal Lineages of the Sudden Oak Death Pathogen, Phytophthora ramorum}, volume={99}, ISSN={["1943-7684"]}, DOI={10.1094/PHYTO-99-7-0792}, abstractNote={Phytophthora ramorum, the causal agent of sudden oak death and ramorum blight, is known to exist as three distinct clonal lineages which can only be distinguished by performing molecular marker-based analyses. However, in the recent literature there exists no consensus on naming of these lineages. Here we propose a system for naming clonal lineages of P. ramorum based on a consensus established by the P. ramorum research community. Clonal lineages are named with a two letter identifier for the continent on which they were first found (e.g., NA = North America; EU = Europe) followed by a number indicating order of appearance. Clonal lineages known to date are designated NA1 (mating type: A2; distribution: North America; environment: forest and nurseries), NA2 (A2; North America; nurseries), and EU1 (predominantly A1, rarely A2; Europe and North America; nurseries and gardens). It is expected that novel lineages or new variants within the existing three clonal lineages could in time emerge.}, number={7}, journal={PHYTOPATHOLOGY}, author={Gruenwald, Niklaus J. and Goss, Erica M. and Ivors, Kelly and Garbelotto, Matteo and Martin, Frank N. and Prospero, Simone and Hansen, Everett and Bonants, Peter J. M. and Hamelin, Richard C. and Chastagner, Gary and et al.}, year={2009}, month={Jul}, pages={792–795} }
 @article{park_park_veeraraghavan_jung_lee_blair_geiser_isard_mansfield_nikolaeva_et al._2008, title={Phytophthora database: a forensic database supporting the identification and monitoring of Phytophthora}, volume={92}, ISSN={["1943-7692"]}, DOI={10.1094/PDIS-92-6-0966}, abstractNote={Phytophthora spp. represent a serious threat to agricultural and ecological systems. Many novel Phytophthora spp. have been reported in recent years, which is indicative of our limited understanding of the ecology and diversity of Phytophthora spp. in nature. Systematic cataloging of genotypic and phenotypic information on isolates of previously described species serves as a baseline for identification, classification, and risk assessment of new Phytophthora isolates. The Phytophthora Database (PD) was established to catalog such data in a web-accessible and searchable format. To support the identification of new Phytophthora isolates via comparison of their sequences at one or more loci with the corresponding sequences derived from the isolates archived in the PD, we generated and deposited sequence data from more than 1,500 isolates representing the known diversity in the genus. Data search and analysis tools in the PD include BLAST, Phyloviewer (a program for building phylogenetic trees using sequences of selected isolates), and Virtual Gel (a program for generating expected restriction patterns for given sequences). The PD also provides a customized means of storing and sharing data via the web. The PD serves as a model that easily can be adopted to develop databases for other important pathogen groups.}, number={6}, journal={PLANT DISEASE}, author={Park, Jongsun and Park, Bongsoo and Veeraraghavan, Narayanan and Jung, Kyongyong and Lee, Yong-Hwan and Blair, Jaime E. and Geiser, David M. and Isard, Scott and Mansfield, Michele A. and Nikolaeva, Ekaterina and et al.}, year={2008}, month={Jun}, pages={966–972} }
 @article{ivors_garbelotto_vries_ruyter-spira_hekkert_rosenzweig_bonants_2006, title={Microsatellite markers identify three lineages of Phytophthora ramorum in US nurseries, yet single lineages in US forest and European nursery populations}, volume={15}, ISSN={["1365-294X"]}, DOI={10.1111/j.1365-294X.2006.02864.x}, abstractNote={Analysis of 12 polymorphic simple sequence repeats identified in the genome sequence of Phytophthora ramorum, causal agent of ‘sudden oak death’, revealed genotypic diversity to be significantly higher in nurseries (91% of total) than in forests (18% of total). Our analysis identified only two closely related genotypes in US forests, while the genetic structure of populations from European nurseries was of intermediate complexity, including multiple, closely related genotypes. Multilocus analysis determined populations in US forests reproduce clonally and are likely descendants of a single introduced individual. The 151 isolates analysed clustered in three clades. US forest and European nursery isolates clustered into two distinct clades, while one isolate from a US nursery belonged to a third novel clade. The combined microsatellite, sequencing and morphological analyses suggest the three clades represent distinct evolutionary lineages. All three clades were identified in some US nurseries, emphasizing the role of commercial plant trade in the movement of this pathogen.}, number={6}, journal={MOLECULAR ECOLOGY}, author={Ivors, K and Garbelotto, M and Vries, IDE and Ruyter-Spira, C and Hekkert, BT and Rosenzweig, N and Bonants, P}, year={2006}, month={May}, pages={1493–1505} }
 @article{tyler_tripathy_zhang_dehal_jiang_aerts_arredondo_baxter_bensasson_beynon_et al._2006, title={Phytophthora genome sequences uncover evolutionary origins and mechanisms of pathogenesis}, volume={313}, ISSN={["1095-9203"]}, DOI={10.1126/science.1128796}, abstractNote={Draft genome sequences have been determined for the soybean pathogen Phytophthora sojae and the sudden oak death pathogen Phytophthora ramorum. Oömycetes such as these Phytophthora species share the kingdom Stramenopila with photosynthetic algae such as diatoms, and the presence of many Phytophthora genes of probable phototroph origin supports a photosynthetic ancestry for the stramenopiles. Comparison of the two species' genomes reveals a rapid expansion and diversification of many protein families associated with plant infection such as hydrolases, ABC transporters, protein toxins, proteinase inhibitors, and, in particular, a superfamily of 700 proteins with similarity to known oömycete avirulence genes.}, number={5791}, journal={SCIENCE}, author={Tyler, Brett M. and Tripathy, Sucheta and Zhang, Xuemin and Dehal, Paramvir and Jiang, Rays H. Y. and Aerts, Andrea and Arredondo, Felipe D. and Baxter, Laura and Bensasson, Douda and Beynon, Jim L. and et al.}, year={2006}, month={Sep}, pages={1261–1266} }
 @article{kang_blair_geiser_khang_park_gahegan_o'donnell_luster_kim_ivors_et al._2006, title={Plant pathogen culture collections: It takes a village to preserve these resources vital to the advancement of agricultural security and plant pathology}, volume={96}, ISSN={["1943-7684"]}, DOI={10.1094/PHYTO-96-0920}, abstractNote={ABSTRACT Plant pathogen culture collections are essential resources in our fight against plant disease and for connecting discoveries of the present with established knowledge of the past. However, available infrastructure in support of culture collections is in serious need of improvement, and we continually face the risk of losing many of these collections. As novel and reemerging plant pathogens threaten agriculture, their timely identification and monitoring depends on rapid access to cultures representing the known diversity of plant pathogens along with genotypic, phenotypic, and epidemiological data associated with them. Archiving such data in a format that can be easily accessed and searched is essential for rapid assessment of potential risk and can help track the change and movement of pathogens. The underexplored pathogen diversity in nature further underscores the importance of cataloguing pathogen cultures. Realizing the potential of pathogen genomics as a foundation for developing effective disease control also hinges on how effectively we use the sequenced isolate as a reference to understand the genetic and phenotypic diversity within a pathogen species. In this letter, we propose a number of measures for improving pathogen culture collections.}, number={9}, journal={PHYTOPATHOLOGY}, author={Kang, Seogchan and Blair, Jaime E. and Geiser, David M. and Khang, Chang-Hyun and Park, Sook-Young and Gahegan, Mark and O'Donnell, Kerry and Luster, Douglas G. and Kim, Seong H. and Ivors, Kelly L. and et al.}, year={2006}, month={Sep}, pages={920–925} }