Zebra Chip Disease, Candidatus Liberibacter, and Potato Psyllid: A Global Threat to the Potato Industry

Zebra chip (ZC), a new and economically important disease of potato in the United States, Mexico, Central America, and New Zealand, is caused by the bacterium Candidatus Liberibacter solanacearum, transmitted to potato by the potato psyllid, Bactericera cockerelli. The disease has caused millions of dollars in losses to the potato industry. Whole crops have been rejected because of ZC, occasionally leading to abandonment of entire fields. Plant growth and yield are severely affected by the disease. Chips or fries processed from ZC-infected tubers exhibit dark stripes that become markedly more visible with frying, and hence are commercially unacceptable. Additionally, the disease causes serious losses to the fresh market, tablestock and export potato industry. ZC-infected tubers generally do not sprout and if they do, produce hair sprouts, weak, or short-lived plants. Furthermore, there are indications that ZC symptoms might develop in tubers during storage. All commercial potato cultivars are susceptible to ZC, thus management tactics targeted against the potato psyllid are currently the only means to effectively manage the disease. An overview of ZC history, geographic distribution, biology, epidemiology, and management are discussed.