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
Scarlet Crush™
Our new Honeycrisp/Pink Lady® cross is sweet with citrusy notes, plus all that famous Honeycrisp snap and juiciness. Up to to 3” pink/rosy-red fruit is uniform, conical and very attractive. A fine cooking and fresh-eating apple. Keeps up to 6 months. Ripens as early as late September. USPPAF. Best pollinators: Starkspur® Red Rome Beauty, Stark® Jon-A-Red® Jonathan or any Golden Delicious. Zones: 3-6.
Fruits
December 8, 2016
Stark Bro’s Nurseries & Orchards Co. 2017 Variety Showcase [Slideshow]
For more information on these varieties, contact Stark Bro’s Nurseries & Orchards. Stark Bro’s Nurseries & Orchards P.O. Box 398 Read More
Past industry efforts to discover Paradox hybrid seedlings (Juglans hindsii x J. regia) with superior traits have led to advanced selections of Paradox clones, each with unique characteristics. The University of California selection, RX 1, is a top-choice for Sacramento Valley walnut orchardists and others looking for resistance to Phytopthora and good survivability. RX 1 is a cross of Juglans microcarpa x J. regia. It is showing to be one of the most adaptable walnut rootstocks, producing a large tree with the highest yields in replicated trials. USPP#20,649 P3
Fruits
December 7, 2016
Sierra Gold Nursery 2017 Variety Showcase [Slideshow]
Sierra Gold Nurseries in Yuba City, CA, offers two walnut rootstocks, a salt-tolerant pistachio rootstock, and more. Read More
Action shot of an automated strawberry picker from Harvest CROO
Equipment
December 6, 2016
USDA Announces $3 Million For Robotic Agriculture Research
More evidence being found about how people can benefit from automation in the field. Read More
billevans
Apple Grower of the Year
December 6, 2016
2014 Apple Grower Of The Year Bill Evans Dies
Legendary apple grower Bill Evans, who along with his wife, Jeannette, farmed more apple acreage than any grower in the Read More
weedy watermelon field
Crop Protection
December 6, 2016
New Fact Sheet Analyzes Weed Seeds And Their Longevity
Topics covered include how weed seeds travel, when they germinate, and ways they can be eliminated. Read More
Field trials are one component being used to evaluate water and nitrogen use efficiency in lettuce.  A wide array of germplasm is being screened including cultivars of leaf, romaine, iceberg and butter types, mapping populations and non-domesticated primitive types and wild lettuce species.   Photo credit: David Still
Crop Protection
December 6, 2016
Scientists Aim To Improve Nitrogen, Water Use Efficiency In Lettuce
Genetic research intends to develop varieties with enhanced nutrient uptake. Read More
Cannabis plant closeup
Citrus
December 6, 2016
Report: Florida Cannabis Business To Approach $2 Billion By 2020
Lofty projections include a compound annual growth rate of 140%. Read More
Growers participate in a real-time industry survey session at the 2016 Florida Citrus Show
Citrus
December 6, 2016
Florida Citrus Community Tasked To Unify For Stronger Future
A group effort is necessary to forge ahead. Read More
field shot the Produce Peddler Colorado
Crop Protection
December 6, 2016
Orondis Opti Fungicide Receives Registration In Premix Formulation
The product provides control of Oomycete diseases in vegetables and other specialty crops. Read More
BlackPearl® is the best early season cherry, ripening 10 days before Bing and around Chelan. It has exceptional flavor and is extremely firm and crunchy. BlackPearl® is medium size with 20% sugar and keeps better that most other cherries. The tree is hardy and canker resistant. Early season bloom, S4 unknown.
Fruits
December 6, 2016
Fowler Nurseries, Inc. 2017 Variety Showcase [Slideshow]
For more information on these varieties, contact Fowler Nurseries, Inc. Fowler Nurseries, Inc. 525 Fowler Rd. Newcastle, CA 9565827 Phone: Read More
The Latest
Fruits
December 8, 2016
Stark Bro’s Nurseries & Orchards Co.…
For more information on these varieties, contact Stark Bro’s Nurseries & Orchards. Stark Bro’s Nurseries & Orchards P.O. Box 398 Read More
Fruits
December 7, 2016
Sierra Gold Nursery 2017 Variety Showcas…
Sierra Gold Nurseries in Yuba City, CA, offers two walnut rootstocks, a salt-tolerant pistachio rootstock, and more. Read More
Equipment
December 6, 2016
USDA Announces $3 Million For Robotic Ag…
More evidence being found about how people can benefit from automation in the field. Read More
Apple Grower of the Year
December 6, 2016
2014 Apple Grower Of The Year Bill Evans…
Legendary apple grower Bill Evans, who along with his wife, Jeannette, farmed more apple acreage than any grower in the Read More
Crop Protection
December 6, 2016
New Fact Sheet Analyzes Weed Seeds And T…
Topics covered include how weed seeds travel, when they germinate, and ways they can be eliminated. Read More
Crop Protection
December 6, 2016
Scientists Aim To Improve Nitrogen, Wate…
Genetic research intends to develop varieties with enhanced nutrient uptake. Read More
Citrus
December 6, 2016
Report: Florida Cannabis Business To App…
Lofty projections include a compound annual growth rate of 140%. Read More
Citrus
December 6, 2016
Florida Citrus Community Tasked To Unify…
A group effort is necessary to forge ahead. Read More
Crop Protection
December 6, 2016
Orondis Opti Fungicide Receives Registra…
The product provides control of Oomycete diseases in vegetables and other specialty crops. Read More
Fruits
December 6, 2016
Fowler Nurseries, Inc. 2017 Variety Show…
For more information on these varieties, contact Fowler Nurseries, Inc. Fowler Nurseries, Inc. 525 Fowler Rd. Newcastle, CA 9565827 Phone: Read More
Vegetables
December 6, 2016
Rupp Seeds 2016 Vegetable Variety Showca…
For more information, contact, Rupp Seeds: 17919 County Rd. B, Wauseon, OH 43567 800-700-1199; WEBSITE www.RuppSeeds.com FAX 419-337-5491; EMAIL [email protected] Read More
Farm Marketing
December 6, 2016
Registration Is Open For 32nd Annual Nor…
The six-day event for agritourism operators heads to the Northeast with highlights including bus tours, educational sessions and workshops, and business exchange. Read More
Insect & Disease Update
December 5, 2016
Best Practices For Bactericides Key To V…
Approval finally cleared for antimicrobial applications, and now growers wait and hope to see positive results. Read More
Citrus
December 5, 2016
South Florida Endures Driest November On…
Region has not experienced any significant rainfall since Hurricane Matthew. Read More
Fruits
December 5, 2016
Fall Creek Nursery 2017 Variety Showcase…
For information about these varieties, contact Fall Creek Nursery: Fall Creek Nursery 39318 Jasper Lowell Road Lowell, OR 97452 800-538-30015 [email protected] Read More
Fruits
December 5, 2016
Team Coverage: Fruit And Nut Industry Co…
Can’t make it to the biggest fruit and vegetable conferences? No sweat, we’ll take you there. Read More
Vegetables
December 4, 2016
Rispens Seeds 2016 Vegetable Variety Sho…
For more information, contact Rispens Seeds: 1357 Dutch American Way, P.O. Box 310, Beecher, IL 60401 708-946-6560; WEBSITE RispensSeeds.com FAX Read More
GenNext Growers
December 4, 2016
New Loans Available For Small, Beginning…
USDA recently announced streamlined guaranteed Loans and additional lender category for small-scale operators. Read More