Building regional capacity to manage invasive pests and diseases to safeguard sustainable seed potato trade

Potatoes are increasingly traded globally, raising the risk of spreading quarantined pests and diseases. Organizations like European and Mediterranean Plant Protection Organization (EPPO) and national bodies regulate many of these threats, necessitating a unified approach to pest and disease management. Strengthening National Plant Protection Organizations (NPPOs) is crucial for prompt detection, diagnosis, and containment. 

A GIZ study in East Africa highlighted inadequate capacity and infrastructure as major barriers to cross-border trade, causing mistrust among partner states over diagnostic reliability. Enhancing infrastructure and technical expertise aims to improve diagnostics and foster trust. However, sustained and coordinated action is essential. A regional approach to managing quarantine threats—through strengthened diagnostics, harmonized protocols, and collaboration—can safeguard global potato production, trade, and agricultural productivity.

Global threats to seed potato quality and trade

Bacterial Wilt (BW)

Ralstonia solanacearum, the causal agent of bacterial wilt in potatoes, is listed as a high-risk quarantine organism by the EPPO. It is widespread in tropical, subtropical, and warm temperate regions and is a major threat to solanaceous plants in these areas. While it is endemic in many regions, quarantine regulations help prevent its spread where the disease is absent or rare.

Infected materials, such as potato tubers, can spread the pathogen over long distances, making quarantine inspections and plant sanitation vital for disease control. The pathogen's different races and strains, with varying virulence, pose a significant risk to potato production, especially for countries exporting seed potatoes.

Worldwide distribution of Ralstonia solanacearum.(Courtesy: CABI (2024))

Potato Cyst Nematodes (PCN)

Potato cyst nematodes (PCN), classified as A2 quarantine pests by EPPO, originated in the Andes and spread to Europe with potato cultivation. The two primary species, Globodera rostochiensis and Globodera pallida, form cysts that attach to roots, stolons, tubers, and soil, facilitating their spread through agricultural activities and soil movement. 

PCN populations gradually build up in patches, with farming activities further dispersing them locally and internationally. Infested crops exhibit poor growth, chlorosis, wilting, smaller tubers, and yield loss, with severe economic impacts in temperate regions. This is worsened when virulent pathotypes overcome resistance. To curb their spread, strict regulations govern seed potato movement nationally and internationally.

Worldwide distribution of Potato Cysts Nematodes. (Courtesy: CABI (2024))

Soft Rot Pectobacteria (SRPs)

Pectobacterium and Dickeya are bacterial pathogens that affect a wide range of crops, including potatoes, and spread globally through infected planting materials. Pectobacterium atrosepticum historically caused blackleg in seed potatoes, but more aggressive species have emerged since 2010, leading to stricter certification in seed potato-growing countries. While not classified as quarantine pests by EPPO, they are EU Regulated Non-Quarantine Pests, requiring zero tolerance in potato microplants. Testing is recommended for post-entry quarantine and trade. Diagnostic protocols are available for identifying these pathogens in potatoes and other hosts.

Worldwide distribution of Dickeya solani. (Courtesy: CABI (2024))

Regional Approaches to Capacity Sharing


The rise of plant pests and diseases requires efficient, field-deployable diagnostic tools to manage plant health. With support from GIZ, FAO, and CGIAR initiatives, CIP has enhanced the capacity of regulatory bodies by training them in diagnostic tools like the LAMP assay. These efforts help agencies manage key potato pests, such as bacterial wilt, PCN, and SRPs. Collaboration with national partners, including NPPOs and research institutions, ensures the long-term sustainability of these technologies. 

Technical backstopping and advisory support to Eastern Africa Community (EAC) for regional trade on seed potatoes

The EAC-GIZ FABI project trained laboratory technicians in five EAC states in 2022, focusing on modern diagnostic technologies for potato pests. The goal was to equip trainees to share their knowledge with colleagues. Each state received a Genie Machine and stereo microscope to assist in seed certification.

Training on the use of LAMP Assay for diagnostics of Ralstonia and Potato viruses

Technical Support to the Global Potato Value Chain Working Group

CIP, under the GIZ initiative, enhanced regulatory bodies' capacity in seed potato inspection and certification through hands-on training on the LAMP assay for detecting Ralstonia in Cameroon, Nigeria, and India. This included introducing the technology to regulatory authorities, building staff capacity, and developing strategies for its adoption, while addressing challenges and fostering inter-country learning for successful integration.

Regional Approach to Addressing Invasive Quarantine Pests in East and Southern Africa

With FAO-STDF support, an initiative was launched to enhance diagnostic and management capacity in East and Southern Africa for potato cyst nematodes (PCN) and emerging pests like Pectobacterium and Dickeya. CIP organized sub-regional workshops, training 39 technical staff from NPPOs on the identification and diagnosis of these pests. The training included separate sessions on PCN diagnostics and Pectobacterium and Dickeya detection.

Enhancing Potato Production and Seed Quality in India, Bhutan, and Nepal

Supported by the Seed Equal initiative, CIP held a three-day training in Bangalore for researchers and technical staff from India, Bhutan, and Nepal. The training covered early generation seed production with Rooted Apical Cuttings (RAC) technology and potato disease diagnostics using the LAMP assay. This initiative helps enhance seed systems, improve crop productivity, and meet growing demand for potatoes in the region.

Capacity development on potato pest and diseases diagnosis for partners in the Global Potato Value Chain Working Group Supported by GIZ

Conclusion

While there are differences in SPS system development among countries, cross-border movement of seed and ware potatoes remains common. However, there are gaps in infrastructure, capacities, and procedures for effective SPS implementation. 

Building capacity for SPS systems is vital to align with seed regulations at both national and regional levels, promoting mutual understanding. Strengthening NPPOs' diagnostic capabilities will foster trust, improve market access, and support the growth of the potato value chain in the region.