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

All Vegetables Stories >All Fruits Stories >All Nuts Stories >All Citrus Stories >

The Latest

Apples & PearsBig Apple Crop Expected
September 2, 2014
Generally high quality predicted at U.S. Apple Association Crop Outlook and Marketing Conference. Read More
Apples & PearsBeware Of Fruit Rots During Apple Harvest
September 2, 2014
Conditions lately have been ripe for fungi fiasco. Read More
Apples & PearsThey’re Back! 2014 Brown Marmorated Stink Bug Populat…
September 2, 2014
Pressure building as traps filling up with pest by the hundreds. Read More
Farm ManagementStudy Shows ‘Megadrought’ On The Radar For …
September 2, 2014
Global warming trends fuel parched prediction from scientists. Read More
Farm ManagementTrimble’s Connected Farm Now Includes Field Data Mana…
September 2, 2014
Trimble adds two apps that work with their Connected Farm Web-based solution, providing growers and their advisors with more detailed field information. Read More
FruitsTips To Help You Manage Postharvest Ripening
September 2, 2014
Humidity, ethylene, and temperature can all impact fruit quality. Read More
CitrusHarness The Marketing Power Of Video
September 1, 2014
Multimedia platform is an effective and inexpensive marketing tool for you to attract new customers and keep existing ones loyal to your brand. Read More
Citrus Achievement AwardDespite Industry Challenges, Florida Citrus Leader Has …
September 1, 2014
2014 Florida Grower Citrus Achievement Award winner Mike Sparks feels confident in crop sector's ability to regain strength. Read More
Florida Ag ExpoFood Safety Modernization Act Is On The Plate
September 1, 2014
Florida Ag Expo agenda to serve up important features of looming regulations. Read More
CEU SeriesCEU Series: Put Weeds Out To Pasture
September 1, 2014
No matter where they are, plants out of place can be problematic. Read More
TomatoesProduction Reaches An All-Time High For Processing Toma…
August 29, 2014
A record high is predicted for the 2014 processing tomato crop. Read More
CitrusFlorida Department Of Citrus Knocks NPR Piece Over Juic…
August 28, 2014
Agency goes to bat for the industry regarding statement slighting OJ's health benefits. Read More
Disease ControlLate Blight Update Reveals Heightened Activity
August 28, 2014
While several states in the Northeast have confirmed the presence of late blight, the disease has not been reported in North Dakota or Minnesota. Read More
CitrusFlorida Energy Firm Charged Up About Citrus Biomass Pot…
August 28, 2014
Machine called a game-changer when it comes to a cost-effective, efficient way for tree removal and re-purposing. Read More
EquipmentNew Tractors Improve Maneuverability And Operator Contr…
August 28, 2014
The Magnum Rowtrac tractors from Case IH meet growers’ cropping needs through a wide variety of row spacing and belt options.   Read More
NutsCalifornia County Passes Ordinance To Protect Walnut Gr…
August 27, 2014
Verification of ownership needed to complete sales of valuable nuts. Read More
NutsAlmond Growers Hit By Russian Import Limits
August 27, 2014
Growers reflect on changes to export market in light of produce ban. Read More
Farm ManagementLeadership And Management Expert To Speak At California…
August 27, 2014
Daniel Goleman will make presentation at California State University-Fresno. Read More