Potato Pointers: New Disease, New Problems

Potato Pointers: In With The New: Zebra Chip

In the early days of 2000, potato growers in the southern U.S. were forced to begin dealing with a new problem in their crop. Vines were showing upwardly rolled leaflets, purple or yellow discoloration, aerial tubers, leaf scorch, and early senescence symptoms. At harvest, tubers were afflicted with vascular browning and areas of the internal tissues that were yellowish, translucent, or otherwise discolored. When affected tubers were sliced to make chips or fries, the symptomatic areas of the tubers turned dark brown when fried, yielding a finished product that showed alternating light and dark bands.

This characteristic symptom gave the name “Zebra Chip” to the new problem. This disease is more than a nuisance in chipping production, but other types of production, including French fry and even fresh potatoes, have the potential to be negatively affected.

Initial attempts to decipher what was causing the new disease met with failure, but scientists recognized early on that an insect called the potato psyllid was involved. After eliminating viruses and phytoplasmas (organisms like the ones that cause witch’s broom and purple top in potato) a team of scientists finally determined that the cause was an obscure, very difficult to work with bacterium. This bacterium belongs to the genus Liberibacter (the same group of bacteria responsible for citrus greening) but the final classification and nomenclature of the organism is still pending.

Potato Losses Mounting
There are no food or health safety issues regarding humans associated with the disease but, over the last 15 years, Zebra Chip has been responsible for some very serious losses to growers in Central America and in the southern U.S. Ominously, the disease was found late this summer in the Southern Columbia Basin of Washington and Oregon. In September, samples with characteristic symptoms were submitted to my laboratory in Idaho.

These also tested positive for Zebra Chip. Fortunately for the producers out here in the Pacific Northwest, the disease has only been found at low percentages in affected lots of potatoes.

Producers in the southern production areas where Zebra Chip has been at its most destructive have been able to utilize insecticide programs to manage the pysllid vector and are able to keep the disease in check At the current time researchers believe that the disease may not pose a significant threat to Pacific Northwest potato production or other more northerly productions areas due to the warm climate requirements of the vector.

Researchers also believe that seed potatoes are probably not responsible for movement of the disease. All of the major varieties currently produced are susceptible to Zebra Chip. Will we be able to breed resistant cultivars? Much remains unknown and only time and more research will answer the many questions posed by this new disease.

Zebra Chip has become important enough that a large group of researchers from across the country are working on it with funding from a Specialty Crops Research Initiative grant. Much of the work performed so far is reported on the grant website at http://agrilife.org/zebrachip. The site contains a wealth of information, including photos of vine and tuber symptoms as well as the problems encountered with finished product. A large and comprehensive research effort is currently underway. I’ll try to keep you all informed of new developments.


Leave a Reply

Featured Stories
Business PlanningTake Climate Change — Please [Opinion]
June 30, 2015
It’s a difficult issue because people tend to think of it in terms of something tangible — like the weather. Read More
NutsWalnut Nitrogen Budgeting Critical
June 30, 2015
Applying the right amount of N is not easy because walnuts take a lot, but these days you don’t want to apply too much. Read More
FruitsHighlights From The Ohio Produce Growers And Marketers Summer Tour [Slideshow]
June 30, 2015
American Vegetable Grower magazine made its way to the Ohio Produce Growers and Marketers Association (OPGMA) Summer Tour & Field Read More
Insect ControlAlabama Insect Scouting Report Indicates Armyworm Numbers Have Increased
June 30, 2015
Report discusses caterpillars, sucking pests, and cowpea curculio activity and management. Read More
Nutrient ManagementResearchers Say Cover Crops May Help Save Soil In Flooded Fields
June 30, 2015
According to experts, planting cover crops may help preserve healthy soil in fields in fields left empty this year thanks to flooding. Read More
TomatoesGSPP Accreditation Enables Sakata Seed America To Offer GSPP-Certified Tomato Varieties
June 30, 2015
The seed company is now authorized to store, treat, process, package, and distribute GSPP-certified tomato seed for the NAFTA market. Read More
MarketingThe Power Of Local Food [Opinion]
June 30, 2015
Summer is now in full swing and we have entered what I like to call “the season of farmers markets.” Read More
PotatoesInnovative Technology Is Necessary For Potato Growers To Be Sustainable [Opinion]
June 30, 2015
Historically, there has often been opposition or fear of new agricultural technologies and today is no different, but it is critical that growers have access to technologies that meet consumer demand while using less land and conserving soil, water, and energy. Read More
BerriesRainy Weather Causing High Risk For Phytopthora In Berries
June 29, 2015
With the rainy weather the Midwest has recently received, the conditions for Phytophthora diseases increases. An increased risk for oomycetes, Read More
Apples & PearsWildfires Damage Washington Fruit Businesses
June 29, 2015
More than 1,000 people have been forced to evacuate as a fast-moving wildfire swept into Wenatchee, WA, on Sunday night Read More
The Latest
Business PlanningTake Climate Change — Please [Opinion]
June 30, 2015
It’s a difficult issue because people tend to think of it in terms of something tangible — like the weather. Read More
NutsWalnut Nitrogen Budgeting Critical
June 30, 2015
Applying the right amount of N is not easy because walnuts take a lot, but these days you don’t want to apply too much. Read More
FruitsHighlights From The Ohio Produce Growers And Marketers …
June 30, 2015
American Vegetable Grower magazine made its way to the Ohio Produce Growers and Marketers Association (OPGMA) Summer Tour & Field Read More
Insect ControlAlabama Insect Scouting Report Indicates Armyworm Numbe…
June 30, 2015
Report discusses caterpillars, sucking pests, and cowpea curculio activity and management. Read More
Nutrient ManagementResearchers Say Cover Crops May Help Save Soil In Flood…
June 30, 2015
According to experts, planting cover crops may help preserve healthy soil in fields in fields left empty this year thanks to flooding. Read More
TomatoesGSPP Accreditation Enables Sakata Seed America To Offer…
June 30, 2015
The seed company is now authorized to store, treat, process, package, and distribute GSPP-certified tomato seed for the NAFTA market. Read More
MarketingThe Power Of Local Food [Opinion]
June 30, 2015
Summer is now in full swing and we have entered what I like to call “the season of farmers markets.” Read More
PotatoesInnovative Technology Is Necessary For Potato Growers T…
June 30, 2015
Historically, there has often been opposition or fear of new agricultural technologies and today is no different, but it is critical that growers have access to technologies that meet consumer demand while using less land and conserving soil, water, and energy. Read More
BerriesRainy Weather Causing High Risk For Phytopthora In Berr…
June 29, 2015
With the rainy weather the Midwest has recently received, the conditions for Phytophthora diseases increases. An increased risk for oomycetes, Read More
Apples & PearsWildfires Damage Washington Fruit Businesses
June 29, 2015
More than 1,000 people have been forced to evacuate as a fast-moving wildfire swept into Wenatchee, WA, on Sunday night Read More
Farm ManagementMarketing Tips From GenNext Growers
June 29, 2015
Whether your business is in its beginning stages of development or is already established and in need of increased visibility, Read More
USDA organic logo
Farm ManagementThe ROI On An Organic Checkoff [Opinion]
June 29, 2015
Organic agriculture is more profitable for farmers than conventional agriculture, according to a recent study published in the Proceedings of Read More
VegetablesBiopesticide From Vestaron Receives California Registra…
June 26, 2015
Vestaron Corporation, a developer of insect control products derived from naturally occurring peptides, today announced that its VST-006330-EP biopesticide has Read More
Crop ProtectionZeal SC Miticide Now Registered With Liquid Formulation
June 26, 2015
Valent U.S.A. Corporation announced that Zeal SC Miticide has been registered by the EPA with a new liquid formulation that Read More
PotatoesBlack Gold Farms Kicks Off Red Potato Harvest In Southe…
June 26, 2015
American Vegetable Grower magazine’s Top 100 Grower Black Gold Farms kicked off fresh red potato harvest in Southeast Missouri this Read More
CucurbitsNational Watermelon Association Designs Patriotic Car F…
June 26, 2015
The National Watermelon Association (NWA), in conjunction with NASCAR racer Ross Chastain’s season long sponsors Watermelon.org and Helena Chemical, want Read More
Disease ControlQuintec Fungicide Receives Label For Bacterial Spot Sup…
June 26, 2015
Quintec fungicide from Dow AgroSciences, known as an effective treatment for suppressing bacterial spot in peppers, is now available to Read More
Crop ProtectionStay A Step Ahead Of Weeds
June 26, 2015
Weed control can be a tricky and costly task made all the more difficult by herbicide resistance and the push Read More