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Wisconsin Department of Agriculture, Trade and Consumer Protection Wisconsin Pest Survey Report s 2009 http://pestsurvey.wi.gov /. Corky Ringspot Survey Powdery Scab Survey. Anette Phibbs, DATCP, Plant Industry Laboratory 4702 University Ave, Madison WI 53702.
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Wisconsin Department of Agriculture, Trade and Consumer Protection Wisconsin Pest Survey Reports 2009 http://pestsurvey.wi.gov/ • Corky Ringspot Survey • Powdery Scab Survey Anette Phibbs, DATCP, Plant Industry Laboratory 4702 University Ave, Madison WI 53702
Wisconsin Department of Agriculture, Trade and Consumer Protection Wisconsin Pest Survey Report 2009 Potato Survey for Corky Ringspot Survey Corky Ringspot Disease in the US • California, • Florida, • Idaho, • Washington • Oregon • Michigan • Minnesota • Wisconsin (N. C. Gudmestad, I. Malik and J.S. Pasche, Plant Disease (2008) 92(8):1254) A. Phibbs
Tobacco Rattle Virus (TRV) and Nematodes TRV is transmitted by Stubby root nematodes Trichodorus spp. and Paratrichodorus spp. These nematodes are present in Wisconsin. Hosts range is huge: potatoes, tomatoes, peppers, including many weeds, annuals and perennials (white & red clover, oats). Non-hosts are alfalfa, corn, barley, rye, wheat, carrots and pumpkin. Wisconsin Department of Agriculture, Trade and Consumer Protection Wisconsin Pest Survey Report 2009 Potato Survey for Corky Ringspot Survey ¼ inch Nematodes in a 1.5ml tube. A. Phibbs
Wisconsin Department of Agriculture, Trade and Consumer Protection Wisconsin Pest Survey Report Perennials Infected with Tobacco Rattle Virus Barrenwort Bleeding heart Coral bells Peony Hosta Astilbe A. Phibbs
Symptoms of CRS include necrotic brown rings in Ranger Russet. Brown corky flecks caused by CRS in Russet Burbank. Photo courtesy of Jim Crosslin, USDA-ARS, Prosser, WA Photo courtesy of Jim Crosslin, USDA-ARS, Prosser WA Wisconsin Department of Agriculture, Trade and Consumer Protection Wisconsin Pest Survey Report 2009 Potato Survey for Corky Ringspot Survey
Wisconsin Department of Agriculture, Trade and Consumer Protection Wisconsin Pest Survey Plant Industry Laboratory • Laboratory testing is performed at Plant Industry Laboratory. • We use nucleic acid assays, RT-PCR (reverse transcription polymerase chain reaction). References: D.J. Robinson, Journal or Virological Methods. 1992, 40, 57-66.” Detection of tobacco rattle virus by reverse transcription and polymerase chain reaction.”
Wisconsin Department of Agriculture, Trade and Consumer Protection Wisconsin Pest Survey Plant Industry Laboratory • We checked all RNA extractions by simultaneously testing for a beta-tubulin reference gene and tobacco rattle virus RNA. References: Mohan Kumar et al., J. Agric. Food Chem. 2007, 55, 1674-1678. “Extraction of RNA from Fresh, Frozen, and Lyophilized Tuber and Root Tissues.”
Survey Results A total of 150 fields in 14 counties tested. 19 Potato producers participated. 50 samples from seed producing fields. 100 from non-seed, fresh vegetable or processing potatoes. All samples tested negative for Tobacco rattle virus, the virus that causes Corky ringspot disease in potatoes. Testing will continue in 2010.
Wisconsin Department of Agriculture, Trade and Consumer Protection Wisconsin Pest Survey Report 2009 Potato Survey for Powdery Scab A. Phibbs A. Phibbs Symptoms of Powdery Scab on Potato Tubers, Spongospora subterranea (Wallr.) Lagerh f.sp. subterranea Tomlinson DATCP
Wisconsin Department of Agriculture, Trade and Consumer Protection Wisconsin Pest Survey Report 2009 Potato Survey for Powdery Scab A. Phibbs Common Scab, Streptomyces scabies, a bacterial disease
Wisconsin Department of Agriculture, Trade and Consumer Protection Wisconsin Pest Survey Report 2009 Potato Survey for Powdery Scab • Powdery Scab Biology • Spongosporasubterranea f.sp. subterraneais a soil borne slime fungus (Plasmodiophorales). • Swimming spores (zoospores) infect roots, multiply in plant tissue and infect tubers. • They form durable resting sporeballs (cystosori) on tuber skin and roots. • Cystosori survive in soil for at least 6 years and survive passage thru animal digestive tract. • Cystosori release more zoospores, go thru several infection cycles during a growing season. Powdery scab sporeball = cystosori. A. Phibbs • Powdery scab infects potato, tomato, bell pepper, and Solanaceous weeds: Jimsonweed, groundcherry, nightshade, colt’s foot, wild tabacco and many more.
Wisconsin Department of Agriculture, Trade and Consumer Protection Wisconsin Pest Survey Report 2009 Potato Survey for Powdery Scab • Conditions Favoring Disease • Cool temperate summers (Soil temperatures of 52F to 64F) • Alternate periods of wet and dry soil,(Simulated by irrigation) • Excess moisture during tuber set. • Environmental conditions may be more important than amount of inoculum. A. Phibbs Pustules of Powdery scab on Red Norland Potato.
Wisconsin Department of Agriculture, Trade and Consumer Protection Wisconsin Pest Survey Report 2009 Potato Survey for Powdery Scab Spread of Powdery scab • Infected seed potatoes • Contaminated soil, field to field movement of soil on equipment, tires, boots, … • Manure or slurry • Spore ball carrying dust in storage • Grading lines A. Phibbs
Powdery scab symptoms on roots of potato. Powdery scab produces root galls on a resistant potato varietiesand re-infect soils. Root Galls Magnified Root Gall A. Phibbs
Wisconsin Department of Agriculture, Trade and Consumer Protection Wisconsin Pest Survey Report 2009 Potato Survey for Powdery Scab A Brief History of Powdery scab in Wisconsin • 2002 UW Clinic’s Brian Hudelson identifies Powdery scab on a Wisconsin potato sample for the first time. • 2003-2004 DATCP conducts a soil survey of 68 fields in 10 counties. • 6 fields in Adams, Oconto, Langlade and Waushara counties test positive. Powdery scab on potato “Molli”. A. Phibbs
Wisconsin Department of Agriculture, Trade and Consumer Protection Wisconsin Pest Survey Plant Industry Laboratory • Early Detection • PCR detects any life stage of powdery scab (zoospores, plasmodium) in any plant tissue. • Examination under microscope and ELISA depend on presence of mature cystosori, formed in the tuber skin or root galls. A. Phibbs A. Phibbs Powdery scab sporeballs or cystosori under magnification.
Wisconsin Department of Agriculture, Trade and Consumer Protection Wisconsin Pest Survey Plant Industry Laboratory • Laboratory testing is performed at Plant Industry Laboratory. • We use nucleic acid assays, PCR (polymerase chain reaction), • Examine tuber skin with microscopes. References: Qu et.al. (Plant Pathology (2001) 50: 420-426).
Distribution of Powdery Scab in Wisconsin* • Adams • Oconto • Pepin • Portage • Langlade • Waushara* at least one field testing positive in a County. Department of Agriculture, Trade and Consumer Protection
Survey Results • Total number of potato samples processed in 2009: 150 • 19 Potato growers participated in 2009. • Number of samples testing positive for Powdery scab: 17 (9%). • 6 farms tested positive, with a total of 13 fields. Department of Agriculture, Trade and Consumer Protection
Wisconsin Department of Agriculture, Trade and Consumer Protection Wisconsin Pest Survey Report 2009 Potato Survey for Powdery Scab Potato Varieties that tested Positive for Powdery Scab in Wisconsin since 2002: • Burbank (no tuber symptoms) • Gold Rush • (Dark) Red Norland • Norkotah • MegaChip • Molly • Ranger Russet • Russian Banana • Shepody • Silverton (no tuber symptoms) A. Phibbs Powdery Scab Symptoms on Shepody potato.
Wisconsin Department of Agriculture, Trade and Consumer Protection Wisconsin Pest Survey Plant Industry Laboratory Further Analysis of Powdery Scab • DNA sequenced from one sample from each farm that tested positive. • All DNA sequences align 99-100% with Spongospora subterranea subterranea type II. • Two genetically distinct groups (I and II). Reference: Qu, X. & Christ B.J., American J of Potato Research (2004) 81:385-394.
Wisconsin Department of Agriculture, Trade and Consumer Protection Wisconsin Pest Survey Report 2009 Potato Survey for Powdery Scab • The Problem • Affects quality of potatoes (tuber skin blemishes and tumors) • Affects crop productivity • Affects storability • Vectors Potato Mop Top Virus (PMTV) • Creates infection opportunities for other diseases: • Late blight (Phytophthora infestans) • Pink rot (Phytophthora erthroseptica) • Dry rot (Fusarium spp.) • Black dot (Colletotrichum coccodes)
Phytosanitary GuidelinesDiseases of Concern for Exports of Seed Potatoes to Canada and Mexico Viruses Alfalfa Mosaic virus Potato yellow dwarf virus Potato yellowing virus Potato mop top virus (Mexico) Potato spindle tuber viroid PVYn PVYntn Tobacco rattle virus (Mexico) Nematodes and Diseases Potato Cyst Nematode (Globodera rostochiensis, G. pallida) Columbia Root-Knot Nematode (Meloidogyne chitwoodii) “Tropical” Root Rot Nematode (Meloidogyne javanico) Soybean cyst nematode (Heterodera glycines) Potato Wart (Synchytrium endobioticum) Bacterial ringrot(Clavibacter michiganensis subsp. Sepedonicus Brown Rot(Rastonia solanacearum) race2 Source: USDA Excerpt 1/25/2010
Wisconsin Rules ATCP 156, Seed Potato Certification ATCP 21 Plant Inspection and Pest Controlhttp://www.legis.state.wi.us/rsb/code/atcp/atcp021.pdf ATCP 21.14, Potato rot nematode ATCP 21.14, Late Blight Wisconsin Statues Chapter 93 DATCP Chapter 94 Plant Industry http://www.legis.state.wi.us/rsb/stats.html Wisconsin Department of Agriculture, Trade and Consumer Protection Potato Laws and Rules
Wisconsin Department of Agriculture, Trade and Consumer Protection Wisconsin Pest Survey Report 2009 Potato Survey for Corky Ringspot and Powdery Scab 2010 Survey • Testing for TRV and Powdery scab will continue in 2010. • Please continue to participate! • Local contacts for sampling are: Tim Leege (715) 623-3930 and Sara Ott (715) 486-0429. Don’t assume your fields are infected, have them tested.
Wisconsin Department of Agriculture, Trade and Consumer Protection Wisconsin Pest Survey http://pestsurvey.wi.gov/ Acknowledgements • Kristyn Meyers • Rachel Leisso • Amanda Nelson • Sara Ott • Tim Leege • Jim Meyer • USDA Cooperative Pest Survey Program and Specialty Crop Block Grant Program for funding. For more information: anette.phibbs@wi.gov