China suspends seed potato imports from countries affected by zebra chip disease

China has suspended imports of seed potatoes from countries affected by zebra chip disease, including the United States. 

Effective Aug. 1, China introduced new phytosanitary measures to prevent the introduction of Candidatus Liberibacter solanacearum (CLso), a quarantine bacterium associated with diseases affecting potatoes and several other crops.

China also placed strict testing and origin restrictions on tomato, pepper, carrot, coriander, celery, and parsley seeds from affected countries and regions, according to a USDA Foreign Agricultural Service report. 

Zebra chip disease (ZC), associated with CLso, causes discoloration in tubers, rendering them unmarketable. 

According to an announcement by the General Administration of Customs of China and the Ministry of Agriculture and Rural Affairs, the decision follows repeated interceptions of CLso in imported plants during quarantine inspections. Chinese authorities said the new measures are intended to safeguard the country’s agricultural production and ecological security.

China’s new rules apply to countries and regions where CLso is known to occur, including the U.S. The current list also includes Canada, Mexico, the United Kingdom, France, Germany, Italy, Spain, Finland, Sweden, Austria, Belgium, the Czech Republic, Estonia, Greece, Norway, Portugal, Serbia, Israel, Türkiye, South Korea, Morocco, Tunisia, Ecuador, Peru, Guatemala, Honduras, El Salvador, Nicaragua, New Zealand and Australia’s Norfolk Island.

Chinese authorities said the list will be updated as new outbreaks are reported globally or if additional interceptions are made at Chinese ports.

CLso is a phloem-limited bacterium that infects crops belonging to the Solanaceae and Apiaceae families, including potatoes, tomatoes, peppers, carrots, celery, parsley and coriander.

In potatoes, CLso is closely associated with zebra chip disease. Infected plants often show stunted growth, leaf yellowing and poor tuber development. Infected tubers develop characteristic dark stripes when fried, making them unsuitable for potato chips and other processed potato products.

The bacterium is primarily transmitted by psyllid insects. However, infected planting material, including seed potatoes, can also introduce the pathogen into new production areas.

China has also suspended Imports of tomato, pepper, carrot, celery, coriander and parsley seeds from Italy and South Korea. However, trade may resume if the exporting country’s National Plant Protection Organization (NPPO) demonstrates that the planting materials originate from officially recognized CLso-free areas.

Spudman reached out the National Potato Council for comment. A spokesman referred questions to Potatoes USA, the national potato marketing board. Potatoes USA President Blair Richardson said via email: “The National Potato Council takes the lead on trade regulations.”