Zebra Chip in North AmericaZebra Chip in North Americaa new challenge?a new challenge?

Phillip Nolte Phillip Nolte Extension Seed Potato SpecialistExtension Seed Potato Specialist

University of Idaho, Idaho Falls, IDUniversity of Idaho, Idaho Falls, ID

UNECE Seed Potato Meeting, May 31, 2012 , Edinburgh, Scotland, UK UNECE Seed Potato Meeting, May 31, 2012 , Edinburgh, Scotland, UK

Dr. Neil Gudmestad, NDSU Dr. Neil Gudmestad, NDSU

Dr. Andy Jensen, WPC, OPC, IPCDr. Andy Jensen, WPC, OPC, IPC

Photo and source creditPhoto and source creditZC in North AmericaZC in North America

ZC in North ZC in North AmericaAmerica

“ “Zebra Complex” or Zebra Complex” or “ZC”“ZC”

Not just chips (crisps) Not just chips (crisps) Fries Fries Fresh Fresh Seed?Seed?

Disease Disease DiagnosisDiagnosisDisease Disease

DiagnosisDiagnosis

ZC in North AmericaZC in North America

ZC Symptom variabilityZC Symptom variabilityFoliar symptoms similar to Foliar symptoms similar to purple top purple top wilt syndrome wilt syndrome and include:and include: Leaf curlLeaf curl Leaf chlorosis and scorchingLeaf chlorosis and scorching Limited purpling of top leavesLimited purpling of top leaves Twisted stemsTwisted stems

ZC Symptom variabilityZC Symptom variability Symptoms continued:Symptoms continued:

Swollen nodesSwollen nodes Aerial tubersAerial tubers Vascular discoloration and wiltVascular discoloration and wilt Plant deathPlant death

Recent HistoryRecent HistoryRecent HistoryRecent History

ZC in North AmericaZC in North America

North

Dakota

Texas

OklahomaNew Mexico

Colorado

Arizona

Kansas

Arkansas

WyomingSouth

Dakota

Nebraska

Minnesota

Iowa

Montana

Idaho

UtahNevada

California

Washington

Missouri

Louisiana

•.•.•.•.•.

Oregon

•.

Locations where ZC defect has been Locations where ZC defect has been found in USAfound in USA

•.•. •.

•.•. •.•.

Seed Seed ProductionProduction30,000 A30,000 A

Seed Seed ProductionProduction30,000 A30,000 A

SWSW

21,000 21,000 AA

SWSW

21,000 21,000 AA

SESE

207,000 207,000 AA

SESE

207,000 207,000 AA

SCSC

75,000 75,000 AA

SCSC

75,000 75,000 AA

ZC Timeline for PNW - ZC Timeline for PNW - 20112011 September- Columbia Basin of September- Columbia Basin of

WA/ORWA/OR Idaho: Late September/Early Idaho: Late September/Early

OctoberOctober Norkotah sample from packing shed with Norkotah sample from packing shed with

symptoms. symptoms. Found by ISDA inspector. Found by ISDA inspector. Confirmed ZC.Confirmed ZC.

Leavings in field sampled confirmed ZC. Leavings in field sampled confirmed ZC. (Jerome Co)(Jerome Co)

Additional samples found in research plots Additional samples found in research plots in in Kimberly (Twin Falls county) – 0 to Kimberly (Twin Falls county) – 0 to 1.8%1.8%

Samples from commercial fields (Twin Samples from commercial fields (Twin Falls county)Falls county)

Lots of positives at low Lots of positives at low incidenceincidence Most in Central IDMost in Central ID Much lower in WestMuch lower in West Nothing from East as yetNothing from East as yet Many potatoes still in storageMany potatoes still in storage

Current situationCurrent situationCurrent situationCurrent situationZC in IdahoZC in Idaho

WESTWEST

21,000 21,000 AA

WESTWEST

21,000 21,000 AA

SESE

207,000 207,000 AA

SESE

207,000 207,000 AA

CENTRACENTRALL

75,000 75,000 AA

CENTRACENTRALL

75,000 75,000 AA ??

Tuber Tuber SymptomsSymptoms

Tuber Tuber SymptomsSymptoms

ZC in North AmericaZC in North America

Tuber Symptoms Tuber Symptoms

G. Secor

Net Necrosis (PLRV) ZC

Defect of Chips / CrispsDefect of Chips / Crisps Disease causes browning of Disease causes browning of chips chips processed from affected processed from affected potatoespotatoes ZC leads to load and field ZC leads to load and field

rejectionsrejections Initially called “Texas defect” and Initially called “Texas defect” and

then “Zebra Chip” due to then “Zebra Chip” due to alternating light and dark streaks alternating light and dark streaks in finished productin finished product

Discoloration ranges from mild to Discoloration ranges from mild to severesevere

Causal AgentCausal AgentCausal AgentCausal Agent

ZC in North AmericaZC in North America

““Candidatus Liberibacter Candidatus Liberibacter solanacearumsolanacearum” ” (bacterium)(bacterium)Not culturableNot culturableSpread by potato psyllidSpread by potato psyllid

Causal AgentCausal Agent

Psyllid VectorPsyllid VectorPsyllid VectorPsyllid Vector

ZC in North AmericaZC in North America

The Vector: Tomato-Potato PsyllidThe Vector: Tomato-Potato Psyllid

Psyllid behavior and Psyllid behavior and capabilities?capabilities? Stored potatoes?Stored potatoes? Curiosity or long term Curiosity or long term scourge?scourge? SeedSeed ??????

Much is unknown Much is unknown Much is unknown Much is unknown ZC in IdahoZC in Idaho

ZC has not been reported in any ZC has not been reported in any seed seed production area of production area of Canada or USACanada or USA

Disease appears to be independent Disease appears to be independent of seed of seed sourcesource

ZCZC frequently kills eyes, or frequently kills eyes, or produces very produces very weak plantweak plant

Studies underway to determine Studies underway to determine importance importance of seed borne of seed borne inoculuminoculum

ato-tomato psyllid native to USA ato-tomato psyllid native to USA westwest

Host range – prefers Solanaceae: Host range – prefers Solanaceae: potato, tomato, pepper, potato, tomato, pepper, nightshades, but can also develop nightshades, but can also develop on many other plantson many other plants

Occurs annually in WA, OR, and IDOccurs annually in WA, OR, and ID May migrate? but may overwinter May migrate? but may overwinter

here?here? Can be very difficult to detect in Can be very difficult to detect in

the fieldthe field

Importance of infected Importance of infected seed?seed?