Pacific Northwest Vegetable Extension Group

of Washington State University, Oregon State University, and University of Idaho

Newsletter Archives

June 2003 Newsletter

Lindsey du Toit and Debra Inglis, editors
WSU Mount Vernon NWREC
16650 State Rte 536, Mount Vernon, WA 98273-4768
360-848-6140 (tel), 360-848-6159 (fax)

WSU Vegetable Pathology Team Newsletter




Welcome tothe June 2003 edition of Washington State University's Vegetable Pathology Extension Team newsletter, the second edition of the 2003 growing season. This issue focuses on recent research regarding vegetable diseases that has been published in various journals during 2002–03.

If you have questions or comments about vegetable diseases and pests, or WSU's Vegetable Pathology Team, contact Debbie Inglis ( or Lindsey du Toit (


Iris yellow spot of onions in the PNW. Onion growers in the Treasure Valley of ID and eastern OR are now familiar with a virus called Iris yellow spot virus (IYSV). The virus is increasing in prevalence, with 2001 and 2002 seasons experiencing epidemic outbreaks of IYSV that affected seed and bulb crops. There is concern about the potential impact of IYSV on the onion/onion seed industries in WA, particularly as the virus was recently found in CO, AZ, UT, and CA.

Last year, WSU Vegetable Pathology Team members, Lindsey du Toit and Gary Pelter came across several onion seed crops in WA that had plants showing symptoms suggestive of IYSV infection. However, as with most virus diseases, diagnosis based on symptoms was not conclusive and needed laboratory confirmation. The samples were tested by researchers at WSU and at North Carolina State University, but the results remained inconclusive. During the current (2003) season, WSU virologist Hanu Pappu (on the Pullman campus), assisted by Lindsey du Toit and Gary Pelter, will be surveying for this disease in WA. This information will help formulate research and determine the potential impact of IYSV in the PNW. The project is funded by the Pacific Northwest Vegetable Association with matching funds from the Washington State Commission for Pesticide Registration.

  Photo of onion
photo of onion

IYSV belongs to a group of viruses called tospoviruses (from the related virus, tomato spotted wilt virus), which are transmitted by thrips. IYSV is transmitted by onion thrips, but does not appear to be transmitted by the western flower thrips. The virus mainly infects onion, garlic, leek, lisianthus and iris (it was first isolated from iris, hence the name Iris yellow spot virus). So far there is no evidence that the virus can be seedborne.

Symptoms: IYSV can be photogenic, producing very characteristic and eye-catching symptoms; however, it can also infect onions without showing any symptoms! Symptoms include straw-colored ring spots (eyespots) on leaves and flower stalks (scapes). Spots may turn necrotic (dead), spindle-shaped on scapes, and may form a distinct "green-island" effect. Some lesions have concentric rings of alternating green and dead or chlorotic tissue. Lesions may girdle the scape, drying the umbel and reducing seed yield/quality. Dieback or lodging may occur. Bulbs, basal plates, and roots typically show no signs of infection.

photo of onion

Management: Currently, there are no effective measures to reduce the impact of this disease. Where possible, select onion cultivars that are less susceptible to thrips; use virus-free transplants; and control volunteers and culls. There is on-going research in Israel, Brazil and California, where the virus is established and causing economic losses. Researchers and extension professionals in the PNW, CO and UT formed a working group last November to develop cooperative research plans on IYSV. Hanu Pappu, Lindsey du Toit, and Gary Pelter are leading this effort in WA.

Howyou can help with IYSV: If you see symptoms suggestive of IYSV infection in an onion bulb or seed crop in WA, please collect samples and send them to Gary Pelter, WSU Extension Agent, P.O. Box 37 (Courthouse), Ephrata, WA 98823; tel: (509) 754-2011, ext. 413; e-mail: Place the symptomatic plants in a plastic bag, store them in a cool location (i.e., not on the dashboard of your vehicle, exposed to the sun) and transport them to Gary Pelter as soon as possible. The virus can be very difficult, even impossible, to detect if the samples are not tested soon after sampling. Gary Pelter will route all suspect samples to Hanu Pappu in Pullman. It would be helpful if you include a few 'healthy' (non-symptomatic) plants in a separate bag, to help us determine whether the virus may be present in this region without showing symptoms. (The Team thanks Hanu Pappu and Lindsey du Toit for contributing this article)


Graduate Research Assistantship Available

A graduate research assistantship is available in the Department of Plant Pathology at Washington State University. The project, "Transmission of Phytophthora infestans in Volunteer Potato Plants" would allow a student to work towards either a Ph.D. or M.S. degree in plant pathology. For more information access or contact Debbie Inglis ( or Dennis Johnson (

International Carrot Conference

The 30th International Carrot Conference is scheduled for September 7-10, 2003 in Muskegon, Michigan. The contact person is Kathy Walicki: (231) 873-2129;; Oceana County Extension, 210 Johnson St., Hart, MI 49420; fax (231) 873-3710. Full meeting registration fee: $180 (before Aug 15, or $225 after Aug 15); one-day registration fee: $75 (before Aug 15, or $100 after Aug 15).

Leafy Vegetable Workshop

The WSU Vegetable Pathology Team is sponsoring a workshop focusing on the diagnosis and control of diseases of leafy vegetables. The workshop will include hands-on diagnosis training with "live" specimens of diseased plants and/or cultured pathogens, general lectures, information on vegetable disease resources, and utilization of the services provided by the WSU Plant & Insect Diagnostic Labs. The workshop is scheduled for 8:00 to 5:00 pm on July 24, 2003, and will be held at WSU-Mount Vernon. To register, contact Janet Watts at or (360) 848-6123.

Onion Field Day
The WSU Onion Field Day is on Thursday August 28th at Grigg & Sons Farm near Quincy, WA. The contact person is Gary Pelter or (509) 754-2011 ext. 413.

Potato Association of America

The 87th Annual Meeting of the Potato Association of America, "Back to Tradition", will be held August 10-14 at the Red Lion Hotel at the Park in Spokane, WA. For more information:

Vegetable Seed Crops Field Day Coming Soon

The WSU-Mount Vernon Vegetable Seed Crops field day will be held on July 8 at WSU-Mount Vernon, 16650 State Route 536, Mount Vernon, WA. It begins at 3:00 pm. For more information contact Lindsey du Toit ( or Tim Miller (


New and On Sale-Compendium of Pepper Diseases

This new compendium published by APS Press provides a comprehensive presentation of the important pepper diseases of the world. The geographical distribution and impact of each disease, control measures, and epidemiological aspects of diseases as well as plant health problems associated with arthropods, nutritional deficiencies, herbicide injuries, and other abiotic causes are included. The compendium also discusses the botany of pepper, current production practices, and postharvest damage to pepper fruit. The cost is $49. To order online:

New Information on Vegetable Diseases Published during 2002-03

Following is a partial listing of new research information that has been published in various journals during 2002-03 about vegetable diseases. You will need to pay a visit to a library in order to access the journals directly, e.g., through the libraries at the University of Washington (Seattle or Tacoma) or Washington State University (Pullman).

Vegetable Topic
Asparagus Elmer, W. H. 2002. Influence of formononetin and NaCl on mycorrhizal colonization and Fusarium crown and root rot of asparagus. Plant Dis. 86:1318-1324.

Elmer, W. H. 2003. Local and systemic effects of NaCI on root composition, rhizobacteria, and Fusarium crown and root rot of asparagus. Phytopathology 93:186-192.

Reid, T.C., Hausbeck, M. K., and Kizilkaya, K. 2002. Use of fungicides and biological controls in the suppression of Fusarium crown and root rot of asparagus under greenhouse and growth chamber conditions. Plant Dis. 86:493-498.

Beet Soto, M.J., and Gilbertson, R. L. 2003. Distribution and rate of movement of the curtovirus Beet mild curly top virus (family Geminiviridae) in the beet leafhopper. Phytopathology 93:478-484.

Workneh, F., Villanueva, E., Steddom, K., and Rush, C. M. 2003. Spatial association and distribution of Beet necrotic yellow vein virus and Beet soilborne mosaic virus in sugar beet fields. Plant Dis. 87:707-711. (BNYVV is the virus associated with Rhizomania, and can infect both table beets and sugar beets. This disease was recently found in sugar beet fields in WA along the Columbia River, and is a concern for the beet seed industry.)

Broccoli Charron, C. S., Sams, C. E., and Canaday, C. H. 2002. Impact of glucosinolate content in broccoli (Brassica oleracea (Italica group)) on growth of Pseudomonas marginalis, a causal agent of bacterial soft rot. Plant Dis. 86:629-632.

Cintas, N. A., Koike, S. T., and Bull, C. T. 2002. A new pathovar, Pseudomonas syringae pv. allisalensis pv. nov., proposed for the causal agent of bacterial blight of broccoli and broccoli raab. Plant Dis. 86:992-998.

Common Bean Lopez, C. E., Acosta, I. F., Jara, C., Pedraza, F., Gaitian-Solis, E., Gallego, G., Beebe, S., and Tohme, J. 2003. Identifying resistance gene analogs associated with resistances to different pathogens in common bean. Phytopathology 93:88-95.

Strausbaugh, C. A., Miklas, P. N., Singh, S. P., Myers, J. R., and Forster, R. L. 2003. Genetic characterization of differential reactions among host group 3 common bean cultivars to NL-3 K strain of Bean common mosaic necrosis virus. Phytopathology 93:683-690.

Dry Bean Filion, M., St-Arnaud, M., and Jabaji-Hare, S. H. 2003. Quantification of Fusarium solani f. sp phaseoli in mycorrhizal bean plants and surrounding mycorrhizosphere soil using real-time polymerase chain reaction and direct isolations on selective media. Phytopathology 93:229-235.

del Rio, L. E., Lamppa, R. S., and Gross, P. L. 2003. Characterization of the reaction of North Dakota dry bean cultivars to three races of Collectotrichum lindemuthianum. Plant Dis. 87:263-265.



Collins, A., Okoli, C.A.N., Morton, A., Parry, D., Edwards, S.G., & Barbara, D.J. 2003. Isolates of Verticillium dahliae pathogenic to crucifers are of at least three distinct molecular types. Phytopathology 93:364-376.

Li, H., and Sivasithamparam, K. 2003. Breakdown of a Brassica rapa subsp. sylvestris single dominant blackleg resistance gene in B. napus rapeseed by Leptosphaeria maculans field isolates in Australia. Plant Dis. 87:752.

Steventon, L. A., Happstadius, I., Okori, P., and Dixelius, C. 2002. Development of a rapid technique for the evaluation of the response of Brassica napus to Verticillium wilt. Plant Dis. 86:854-858.

Zhao, Y. F., Damicone, J. P., and Bender, C. L. 2002. Detection, survival, and sources of inoculum for bacterial diseases of leafy crucifers in Oklahoma. Plant Dis. 86:883-888.


Kora C., McDonald, M.R., and Boland, G.J. 2003. Sclerotinia rot of carrot. An example of phenological adaptation and bicyclic development by Sclerotinia sclerotiorum. Plant Dis. 87:456-470.

Pryor, B. M., Strandberg, J. O., Davis, R. M., Nunez, J. J. and Gilbertson, R. L. 2002. Survival and persistence of Alternaria dauci in carrot cropping systems. Plant Dis. 86:1115-1122.



Keinath, A. P., Harrison, H. F., Marino, P. C., Jackson, D. M., and Pullaro, T. C. 2003. Increase in populations of Rhizoctonia solani and wirestem of collard with velvet bean cover crop mulch. Plant Dis. 87:719-725.

Lewis Ivey, M. L., Wright, S., & Nuller, S. A. 2002. Report of bacterial leaf spot on collards & turnip leaves in Ohio. Plant Dis. 86:186.

Corn Esker, P. D., and Nutter, F. W., Jr. 2003 Temporal dynamics of corn flea beetle populations infested with Pantoea stewartii, causal agent of Stewart's disease of corn. Phytopathology 93:210-218.
Cover cropping Keinath, A.P., Harrison, H.F., Marino, P.C., Jackson, D.M., and Pullaro, T.C. 2003. Increase in populations of Rhizoctonia solani and wirestem of collard with velvet bean cover crop mulch. Plant Dis. 87:719-725.
Cucumber Pavlou, G. C., Vakalounakis, D. J., and Ligoxigakis, E. K. 2002. Control of root and stem rot of cucumber, caused by Fusarium oxysporum f. sp. radicis-cucumerinum, by grafting onto resistant rootstocks. Plant Dis. 86:379-382.

Peterson, P. D., and Campbell, C. L. 2002. Prevalence and ecological association of foliar pathogens of cucumber in North Carolina, 1996-1998. Plant Dis. 86:1094-1100.

Schuerger, A. C., and Hammer, W. 2003. Suppression of powdery mildew on greenhouse-grown cucumber by addition of silicon to hydroponic nutrient solution is inhibited at high temperature. Plant Dis. 87:177-185.

Cucurbits Sevik, M. A., and Arli-Sokmen, M. 2003. Viruses infecting cucurbits in Samsun, Turkey. Plant Dis. 87:341-344.

Shishkoff, N., and McGrath, M. T. 2002. AQ10 biofungicide combined with chemical fungicides of AddQ spray adjuvant for control of cucurbit powdery mildew in detached leaf culture. Plant Dis. 86:915-918.

Food safety Buck, J. W., Walcott, R. R., Beuchat, L. R. 2003. Recent trends in microbiological safety of fruits and vegetables. Online. Plant Health Progress doi:10.1094/PHP-2003-0121-01-RV.
Fungicides Gent, D. H., Schwartz, H. F., and Nissen, S.J. 2003. Effect of commercial adjuvants on vegetable crop fungicide coverage, absorption, and efficacy. Plant Disease 87:591-597.

Stivers-Young, L. J., Kuhar, T.P., and Hoffmann, M.P. 2003. Pesticide use changes in New York vegetables: 1978 to 1998. Online. Journal of Extension, Vol. 41.

Green bean Flores-Estevez, N., Acosta-Gallegos, J. A., and Silva-Rosales, L. 2003. Bean common mosaic virus and bean common mosaic necrosis virus in Mexico. Plant Dis. 87:21-25.

Lapidot, M. 2002. Screening common bean (Phaseolus vulgaris) for resistance to tomato yellow leaf curl virus. Plant Dis. 86:429-432.

Shah, D. A., Dillard, H. R., and Cobb, A. C. 2002. Alternatives to vinclozolin (Ronilan) for controlling gray and white mold on snap bean pods in New York. Online. Plant Health Progress doi:10.1094/PHP-2002-0923-01-RS.

Green pea

Fukumoto, F., Masuda, Y., and Hanada, K. 2003. Pea tissue necrosis induced by cucumber mosaic virus alone or together with watermelon mosaic virus. Plant Dis 87:324-328.

Peters, R. D., and Grau, C. R. 2002. Inoculation with nonpathogenic Fusarium solani increases severity of pea root rot caused by Aphanomyces euteiches. Plant Dis. 86:411-414.

Xue, A. G. 2003. Biological control of pathogens causing root rot complex in field pea using Clomostachys rosea strain ACM941. Phytopathology 93:329-335.

Lettuce Barak, J. D., and Gilbertson, R. L. 2003. Genetic diversity of Xanthomonas campestris pv. vitians, the causal agent of bacterial leafspot of lettuce. Phytopathology 93:596-603.

Hao, J. J., Subbarao, K. V., and Koike, S. T. 2003. Effects of broccoli rotation on lettuce drop caused by Sclerotinia minor and on the population density of sclerotia in soil. Plant Dis. 87:159-166.

Pernezny, K., Nagata, R., Raid, R. N., Collins, J., and Carroll, A. 2002. Investigation of seed treatments for management of bacterial leaf spot of lettuce. Plant Dis. 86:151-155.

Sahin, F., Abbasi, P. A., Lewis Ivey, M. L., Zhang, J., and Miller, S. A. 2003. Diversity among strains of Xanthomonas campestris pv. vitians from lettuce. Phytopathology 93:64-70.


du Toit, L.J., Inglis, D.A., and Pelter, G.Q. 2003. Fusarium proliferatum pathogenic on onion bulbs in Washington. Plant Dis. 87:750.

Gitaitis, R., Diaz-Perez, J. C., Walcott, R., and Sanders, H. 2002. Effects of mulch & irrigation on center rot of onion. Phytopathology 92:S149.

Gitaitis, R. D., Walcott, R. R., Wells, M. L., Diaz Perez, J. C., and Sanders, F. H. 2003. Transmission of Pantoea ananatis, causal agent of center rot of onion, by tobacco thrips, Frankliniella fusca. Plant Dis. 87:675-678.

Gistaitis, R., Wells, L., Sanders, H., Riley, D., and Walcott, R. 2002. Association of Pantoea ananatis with tobacco thrips, Frankliniella fusca. Phytopathology 92:S149

Nielsen, K., Yohalem, D. S., and Jensen, D. F. 2002. PCR detection and RFLP differentiation of Botrytis species associated with neck rot of onion. Plant Dis. 86:682-686.

Sanders, F.H., Langston Jr., D.B., Brock, J.H., and Gitaitis, R.D. 2003. First report of a leaf blight of onion caused by Xanathomonas spp. in Georgia. Plant Dis. 87:749.

Schwartz, H. F., Brown, Jr., W. M., Blunt, T., and Gent, D.H. 2002. Iris yellow spot virus on onion in Colorado. Plant Dis: 86:560.

Spiegel, Y., Burrows, P. M., and Bar-Eyal, M. 2003. A chemoattractant in onion root exudates recognized by Ditylenchus dipsaci in laboratory bioassay. Phytopathology 93:127-132.

Swift, C. E., Wickliffe, E. R., and Schwartz, H. F. 2002. Vegetative compatibility groups of Fusarium oxysporum f. sp. cepae from onion in Colorado. Plant Dis. 86:606-610.

Walcott, R. R., Gitaitis, R. D., Castro, A. C., Sanders, F. H., Jr., and Diaz-Perez, J. C. 2002. Natural infestation of onion seed by Pantoea ananatis, causal agent of center rot. Plant Dis. 86:106-111.

Muskmelon Ficcadenti, N., Sestili, S., Annibali, S., Campanelli, G., Belisario, A., Maccaroni, M., and Corazza, L. Resistance to Fusarium oxysporum f. sp. melonis race 1,2 in muskmelon lines Nad-1 and Nad-2. Plant Dis. 86:897-900.
Pepper Maris, P. C., Joosten, N. N., Peters, D., and Goldbach, R. W. 2003. Thrips resistance in pepper and its consequences for the acquisition and inoculation of Tomato spotted wilt virus by the western flower thrips. Phytopathology 93:96-101.

Matheron, M. E., and Porchas, M. 2002. Suppression of Phytophthora root and crown rot on pepper plants treated with acibenzolar-S-methyl. Plant Dis. 86:292-297.

Rodriguez-Alvarado, G., Fernandez-Pavia, S., Creamer, R., and Liddell, C. 2002. Pepper mottle virus causing disease in chile peppers in southern New Mexico. Plant Dis. 86:603-605.

Sanogo, S. 2003. Chile pepper and the threat of wilt diseases. Online. Plant Health Progress. doi:10.1094/PHP-2003-0430-01-RV.

Yanar, Y., and Miller, S. A. 2003. Resistance of pepper cultivars and accessions of Capsicum spp. to Sclerotinia sclerotiorum. Plant Dis. 87:303-307.


Brown, G. T., DeTar, W. R., Sanden, B. L. and Phene, C. J. 2002. Comparison of drip and sprinkler irrigation systems for applying metam sodium and managing stem rot on potato. Plant Dis. 86:1211-1218.

De Boer, S. H. 2002. Relative incidence of Erwinia carotovora subsp. atroseptica in stolon end and peridermal tissue of potato tubers in Canada. Plant Dis. 86:960-964.

Gent, D. H., and Schwartz, H. F. 2003. Validation of potato early blight disease forecast models for Colorado using various sources of meteorological data. Plant Dis. 87:78-84.

Hervieux, V., Yaganza, E. S., Arul, J. and Tweddell, R. J. 2002. Effect of organic and inorganic salts on the development of Helminthosporium solani, the causal agent of potato silver scurf. Plant Dis. 86: 1014-1018.

Jansky, S. H., and Rouse, D. I. 2003. Multiple disease resistance in interspecific hybrids of potato. Plant Dis. 87:266-272.

Jung, H. W., Yun, W. S., Hahm, Y. I., and Kim, K.-H. 2002. Characterization of tobacco mosaic virus isolated from potato showing yellow leaf mosaic and stunting symptoms in Korea. Plant Dis. 86:112-117.

Michaud, M., Martinez, C., Simao-Beaunoir, A.-M., Belanger, R. R., and Tweddell, R. J. 2002. Selection of antagonist microorganisms against Helminthosporium solani, causal agent of potato silver scurf. Plant Dis. 86:717-720.

Kushalappa, A. C., Lui, L. H., Chen, C. R., and Lee, B. 2002. Volatile fingerprinting (SPME-GC-FID) to detect and discriminate diseases of potato tubers. Plant Dis. 86:131-137.

Miller, J. S., Cummings. T. F., Mikitzel, L. J., and Johnson, D. A. 2002. Influence of timing of harvest in relation to haulm killing and planting date on potato tuber rot caused by Phytophthora infestans. Plant Dis. 86:264-268.

Powelson, M. L., Ludy, R., Partipilo, H., Inglis, D. A., Gundersen, B., and Derie, M. L. Seed borne late blight of potato. Online. Plant Health Progress doi:10.1094/PHP-2002-0129-01-HM.

Rampersad, S. N., and Umaharan, P. 2003. Identification of resistance to Potato yellow mosaic virus -Trinidad isolate (PYMV-TT) among Lycopersicon species. Plant Dis. 87:686-691.

Salas, B., Secor, G. A., Taylor, R. J., and Gudmestad, N. C. 2003. Assessment of resistance of tubers of potato cultivars to Phytophthora erythroseptica and Pythium ultimum. Plant Dis. 87:91-97.

Singh, R. P., McLaren, D. L., Nie, X., and Singh, M. 2003. Possible escape of a recombinant isolate of Potato virus Y by serological indexing and methods of its detection. Plant Dis. 87:679-685.

Visker, M. H. P. W., Keizer, L. C. P., B udding, D. J., Van Loon, L. C., Colon, L. T., and Struik, P. C. 2003. Leaf position prevails over plant age and leaf age in reflecting resistance to late blight in potato. Phytopathology 93:666-674.

Pumpkin Babadoost, M., and Islam, S. Z. 2002. Phytophthora blight on pumpkin. Online. Plant Health Progress doi:10.1094/PHP-2002-1216-01-DG.

Babadoost, M., and Islam, S. Z. 2003. Fungicide seed treatment effects on seedling damping-off of pumpkin caused by Phytophthora capsici. Plant Dis. 87:63-68.

Everts, K. L. 2002. Reduced fungicide applications and host resistance for managing three diseases in pumpkin grown on a no-till cover crop. Plant Dis. 86:1134-1141.

Radish de Boer, M., Bom, P., Kindt, F., Keurentjes, J. J. B., van der Sluis, I., van Loon, L. C., and Bakker, P. A. H. M. 2003. Control of Fusarium wilt of radish by combining Pseudomonas putida strains that have different disease-suppressive mechanisms. Phytopathology 93:626-632.
Seedborne pathogons Walcott, R. R. 2003. Detection of seedborne pathogens. HortTech. 13:40-47.
Spinach Irish, B. M., Correll, J. C., and Morelock, T. E. 2002. The effect of synthetic surfactants on disease severity of white rust on spinach. Plant Dis. 86:791-796.

Irish, B. M., Correll, J. C., Koike, S. T., Schafer, J., and Morelock, T.E. 2003. Identification and cultivar reaction to three new races of the spinach downy mildew pathogen from the United States and Europe. Plant Dis. 87:567-572.

Sullivan, M. J., Damicone, J. P., and Payton, M. E. 2002. The effects of temperature and wetness period on the development of spinach white rust. Plant Dis. 86:753-758.

Sweet Corn Clements, M. J., Kleinschmidt, C. E., Maragos, C. M., Pataky, J. K., and White, D. G. 2003. Evaluation of inoculation techniques for Fusarium ear rot and fumonisin contamination of corn. Plant Dis. 87:147-153.

Figueira, E. L. Z., Blanco-Labra, A., Gerage, A. C., Ono, E. Y. S., Mendiola-Olaya, E., Ueno, Y., and Hirooka, E. Y. 2003. New amylase inhibitor present in corn seeds active in vitro against amylase from Fusarium verticillioides. Plant Dis. 87:233-240.

Michener, P. M., Freeman, N. D., and Pataky, J. K. 2003. Relationships between reactions of sweet corn hybrids to Stewart's wilt and incidence of systemic infection by Erwinia stewartii. Plant Dis. 87:223-228.

Michener, P. M., Pataky, J. K., and White, D. G. 2002. Rates of transmitting Erwinia stewartii from seed to seedlings of a sweet corn hybrid susceptible to Stewart's wilt. Plant Dis. 86:1031-1035.

Michener, P. M., Pataky, J. K., and White, D. G. 2002. Transmission of Erwinia stewartii from plants to kernels and reactions of corn hybrids to Stewart's wilt. Plant Dis. 86:167-172.

Windham, G. L., and Williams, W. P. 2002. Evaluation of corn inbreds and advanced breeding lines for resistance to aflatoxin contamination in the field. Plant Dis. 86:232-234.


Groves, R. L., Walgenbach, J. F., Moyer, J. W., and Kennedy, G. G. 2002. The role of weed hosts and tobacco thrips, Frankliniella fusca, in the epidemiology of tomato spotted wilt virus. Plant Dis. 86:573-582.

Mills, D. J., Coffman, C. B., Teasdale, J. R., Everts, K. L., Abdul-Baki, A. A., Lydon, J. and Anderson, J. D. 2002. Foliar diseases in fresh-market tomato grown in differing bed strategies and fungicide spray programs. Plant Dis. 86:955-959.

Mills, D. J., Coffman, C. B., Teasdale, J. R., Everts, K. L., and Anderson, J. D. 2002. Factors associated with foliar disease of staked fresh market tomatoes grown under differing bed strategies. Plant Dis. 86:356-361.

Muslim, A., Horinouchi, H., and Hyakumachi, M. 2003. Control of Fusarium crown and root rot of tomato with hypovirulent binucleate Rhizoctonia in soil and rock wool systems. Plant Dis. 87:739-747.

Nono-Womdim, R., Swai, I. S., Mrosso, L. K., Chadha, M. L., and Opena, R. T. 2002. Identification of root-knot nematode species occurring on tomatoes in Tanzania and resistant lines for their control. Plant Dis. 86:127-130.

Pietersen, G., and Smith, M. F. 2002. Tomato yellow leaf curl virus resistant tomatoes show resistance to tomato curly stunt virus. Plant Dis. 86:528-534.

Ploeg, A. T. 2002. Effect of selected marigold varieties on root-knot nematodes and tomato and melon yields. Plant Dis. 86:505-508.

Pradhanang, P. M., Momol, M. T., Olson, S. M., and Jones, J. B. 2003. Effects of plant essential oils on Ralstonia solanacearum population density and bacterial wilt incidence in tomato. Plant Dis. 87:423-427.

Sanogo, S., Stevenson, R. E., and Pennypacker, S. P. 2003. Appressorium formation and tomato fruit infection by Colletotrichum coccodes. Plant Dis. 87:336-340.

Werner, N. A., Fulbright, D. W., Podolsky, R., Bell, J., and Hausbeck, M. K. 2002. Limiting populations and spread of Clavibacter michiganensis subsp. michiganensis on seedling tomatoes in the greenhouse. Plant Dis. 86:535-542.

Vegetables Mitkowski, N. A., Van der Beck, J. G., and Abawi, G. S. 2002. Characterization of root-knot nematode populations associated with vegetables in New York State. Plant Dis. 86:840-847.
Watermelon Harveson, R. M., Kimbrough, J. W., and Hopkins, D. L. 2002. Novel use of a pyrenomycetous mycoparasite for management of Fusarium wilt of watermelon. Plant Dis. 86:1025-1030.

Holmes, G. J., and Schultheis, J. R. 2003. Sensitivity of watermelon cultigens to ambient ozone in North Carolina. Plant Dis. 87:428-434.

Keinath, A. P. 2002. Survival of Didymella bryoniae in buried watermelon vines in South Carolina. Plant Dis. 86:32-38.

Walcott, R. R., Castro, A. C., and Gitaitis, R. D. 2002. Role of watermelon blossoms in seed infection by Acidovarax avenae subsp. citrulli. Phytopathology 92:S84.

Walcott, R. R., Gitaitis, R. D., and Castro, A. C. 2003. Role of blossom in watermelon seed infestation by Acidovarax avenae subsp. citrulli. Phytopathology 93:528-534.

Zhou, X. G., and Everts, K. L. 2003. Races and inoculum density of Fusarium oxysporum f. sp. niveum in commercial watermelon fields in Maryland and Delaware. Plant Dis. 87:692-698.


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WSU Mount Vernon NWREC, 16650 State Route 536, Mount Vernon, WA 98273-4768, 360-848-6120
Contact Us: Lindsey du Toit and Carol Miles