Plant Biosecurity For Food Security: Zimbabwe Sounds The Alarm
The faces on the Zoom call flickered into focus just after 9am. Plant health inspectors in khaki shirts, researchers in lab coats, farmers’ union representatives with fields behind them, policy advocates hunched over laptops in Harare and Mutare. On 14 May 2026, they had gathered for one reason: to mark the International Day of Plant Health under a national theme that felt less like a slogan and more like a warning — “Plant Biosecurity for Food Security.”
At the centre of the virtual room was Primrose K Nyaruwata from Zimbabwe’s Plant Quarantine Services Institute (PQSI), the country’s National Plant Protection Organisation. Over the next hour, she pulled back the curtain on a system that quietly guards Zimbabwe’s borders, export markets and granaries. Her message was clear: plant biosecurity is not optional, not in a country that depends on maize, tobacco, wheat, horticulture and small grains to feed itself and earn foreign currency.
Why Plant Biosecurity Matters For Food Security
The International Day of Plant Health is a young observance. The United Nations General Assembly established it in March 2022, building on the International Year of Plant Health (2020–2021). Co-led by the Food and Agriculture Organization (FAO) and the International Plant Protection Convention (IPPC), it exists because a simple, brutal truth keeps repeating itself in fields across the world.
FAO estimates that up to 40 percent of global food crops are lost to plant pests and diseases every year, draining more than USD 220 billion from the world economy. Invasive insects account for roughly USD 70 billion of that. Wheat diseases wipe out between 10 and 28 percent of harvests; maize diseases destroy between 20 and 41 percent in a season. Those percentages are not just numbers — they are empty granaries, cancelled school fees and meals stretched too thin.
The 2025 global theme, “The Importance of Plant Health in One Health,” ties plant health to human, animal and environmental wellbeing. Zimbabwe’s decision to sharpen this to “Plant Biosecurity for Food Security” brings the argument home: if the country does not keep dangerous pests and diseases out — and manage those already inside — its food security and export ambitions under Agenda 2063 and National Development Strategy 1 (NDS1) will stall.
Who Guards Zimbabwe’s Plant Health Borders?
Nyaruwata began with the architecture that underpins Zimbabwe’s plant health system. PQSI sits within the Ministry’s Research Services Department and operates under the Plant Pests and Diseases Act (Chapter 19:08), as well as Zimbabwe’s obligations under the WTO Sanitary and Phytosanitary (SPS) Agreement and the IPPC.
The mandate is wide. PQSI is responsible for:
- Port-of-entry inspections at land borders, airports and cargo terminals.
- Pest surveillance and diagnostics across farming areas.
- Phytosanitary certification for exports.
- Pest risk analysis for new trade flows and plant material.
- Regulatory enforcement of plant health laws.
To carry this load, PQSI works with Seed Services, the Plant Protection Research Institute, the National Genebank, the National Herbarium, the Zimbabwe Revenue Authority (ZIMRA), and international partners such as FAO, the International Institute of Tropical Agriculture (IITA) and the International Potato Center (CIP).
“This is not work that one institution can do alone,” Nyaruwata told participants. Plant health, she argued, touches borders, farms, laboratories, export corridors and climate systems all at once. It demands a whole-of-government and whole-of-society response that includes farmers, exporters, transporters and consumers.
FFA Explainer:
Plant biosecurity refers to the systems, laws, laboratories, border checks and on-farm practices that keep harmful pests and diseases from entering, establishing or spreading in a country. It includes preventing new invasions, detecting outbreaks early, and containing or eradicating them before they damage crops and trade.
Which Pests Are Threatening Zimbabwe’s Crops?
When Nyaruwata turned to the list of pests and diseases on PQSI’s radar, the chat window filled with comments. The threats fall into three broad categories: trade-limiting pests already present in the region, high-priority threats not yet established in Zimbabwe, and familiar invaders like fall armyworm that farmers battle every season.
How Do Trade-Limiting Pests Hit Export Farmers?
Some pests do not just destroy crops in the field; they close doors in foreign markets. Zimbabwe is already grappling with several such pests that trading partners treat as quarantine threats:
- Citrus black spot — a fungal disease that can trigger rejections of citrus shipments.
- False codling moth — a key quarantine pest for markets such as the European Union.
- Fruit fly species — affecting citrus, capsicum, roses and other horticultural exports.
These organisms set the terms of trade. If they are detected in export consignments, importing countries can reject entire shipments, suspend permits or impose stricter conditions. That is why PQSI issued 32,000 phytosanitary certificates in 2023 and achieved 100 percent tobacco export compliance — a workload that signals how tightly Zimbabwe’s export earnings are tied to plant health performance.
For a citrus exporter in Mazowe or Beitbridge, a single consignment rejected at a foreign port is not just a lost load. It is higher inspection costs next season, wary buyers, and months of trying to prove that the problem has been fixed.
Which High-Priority Threats Are Circling The Country?
The more unsettling part of Nyaruwata’s catalogue was the list of pests and pathogens that have not yet established in Zimbabwe but are edging closer through regional trade and climate shifts:
- Asian citrus psyllid and its associated bacterium causing Huanglongbing (citrus greening), one of the most destructive citrus diseases globally.
- Banana Xanthomonas wilt — spreading across East and Central Africa, threatening subsistence and commercial banana plantations.
- Banana bunchy top virus — present in parts of the region and capable of crippling banana production.
- Potato cyst nematode — a soil-dwelling pest with serious implications for potato producers from Nyanga to Mazowe.
- Wheat blast — a fast-spreading fungal disease of deep concern as Zimbabwe scales up winter wheat.
- Xylella fastidiosa — a bacterial pathogen that attacks olives, grapes, almonds, coffee and ornamentals.
- Polyphagous shot hole borer — an ambrosia beetle moving through Southern Africa’s woodlands and orchards.
- Maize lethal necrosis (MLN) — a viral disease complex that has already devastated maize in East Africa.
On MLN, Nyaruwata offered cautious reassurance. Zimbabwe has been conducting 10-year MLN detection surveys with no confirmed detection so far. Yet the surveillance has not stopped, because once this disease is inside, it reshapes the entire maize sector.
Participants also flagged Clavibacter michiganensis subsp. nebraskensis, the bacterial pathogen behind Goss’s wilt in maize that has been spreading in South Africa. The consensus in the chat was blunt: monitoring has to step up before it crosses the Limpopo in infected seed or contaminated machinery.
What Has Fall Armyworm Taught Zimbabwe?
Some threats are no longer at the gate; they are in the homestead field. The fall armyworm (Spodoptera frugiperda) has become a household name in Zimbabwe since it swept across sub-Saharan Africa from the Americas in 2016.
Research published in the journal Food and Energy Security found that farm households affected by fall armyworm are 12 percent more likely to experience hunger, with maize yield losses in heavily infested fields potentially exceeding 70 percent. The pest feeds on more than 350 plant species — from maize and sorghum to rice, sugarcane, cotton, soyabeans, potatoes, tobacco, onions and tomatoes.
For a smallholder family in Mhondoro or Lupane, fall armyworm is not an academic case study. It is the difference between keeping enough grain to last to the next harvest or entering the lean season early. It is also a lesson in what happens when an invasive species arrives before biosecurity systems are fully ready.
How Strong Is Zimbabwe’s Diagnostic Capacity?
Detection sits at the heart of any plant biosecurity system. If inspectors and scientists cannot identify a pest or pathogen quickly and accurately, they cannot stop it.
Nyaruwata described PQSI’s diagnostic toolkit, which combines morphological methods (examining the physical characteristics of pests and pathogens) with molecular techniques in the laboratory, supported by post-entry quarantine inspections.
Zimbabwe has made some important strides:
- A Phytosanitary Capacity Evaluation (2023–2024) completed with IPPC and FAO support, under an EU-funded project that also included eight other African countries.
- Capacity building through the Stosa project, which strengthened pest risk analysis and supported adoption of e-Phyto — electronic phytosanitary certificates via the global e-Phyto hub.
- A new quarantine centre at Beitbridge border post, complementing inspectors based at airport cargo handling facilities.
- A one-stop commercial processing facility at Gungunyana to make compliance easier for exporters.
Yet the gaps remain sharp. Limited molecular diagnostic capacity, fragmented surveillance systems, inconsistent funding and staffing shortages slow down sample processing and create blind spots.
“We know where the weaknesses are,” Nyaruwata said. “What we need is the investment to address them.”
FFA Explainer:
Molecular diagnostics use tools like DNA and RNA analysis to identify pests and pathogens. They can detect organisms that look similar under a microscope but behave very differently in the field, and they can pick up infections at an early stage, before symptoms are obvious on plants.
What Is The Pay-Off From Strong Plant Health Systems?
Nyaruwata was careful to balance the list of threats with proof that good plant health systems pay off economically. She highlighted a series of market access wins that depend directly on PQSI’s performance.
- China citrus export protocol — concluded and operational, with Zimbabwe shipping citrus to China from 2023 and 46 containers moved in the first season.
- Avocado export protocol with China — concluded in 2024.
- Blueberry export protocol with China — concluded in 2025.
- 32,000 phytosanitary certificates issued in 2023, with full compliance on tobacco exports.
For emerging horticulture hubs such as Chegutu, Mazowe and Nyanga, these protocols are more than diplomatic paperwork. They are the bridge between a hillside orchard and a supermarket shelf in Shanghai or Beijing. They also align with NDS1’s focus on diversifying exports and the African Continental Free Trade Area’s promise of larger regional markets.
The scaling up of the e-Phyto system is expected to cut processing costs and reduce turnaround times for phytosanitary certificates, offering a practical gain for exporters and farmers who operate on tight margins and in narrow harvest windows.
Why Informal Trade Is A Biosecurity Blind Spot
One of the liveliest parts of the webinar focused on the border that cannot be fully inspected: the informal trade routes linking Zimbabwe with Zambia, Mozambique, South Africa, Botswana and Namibia.
Every day, small consignments of vegetables, fruits, seeds, seedlings and cuttings cross these porous borders without paperwork or inspections. For many households, this trade is a vital livelihood. For PQSI, it is a recognised pathway for pest and disease introduction that is extremely hard to manage through regulation alone.
To reduce risk, PQSI has:
- Run outreach and awareness campaigns targeting travellers, farmers and small traders.
- Reduced the cost and friction of official import permits — a non-commercial import permit costs just USD 1.
- Enabled inspectors at exit ports to issue permits directly.
Yet, as several participants noted, behaviour does not change overnight, especially when informal trade puts food on the table. Others raised the growing risk of courier and cargo shipments — from global firms like DHL and FedEx to smaller operators — carrying seeds, bulbs or cuttings ordered online.
Nyaruwata confirmed that inspectors are present at cargo areas and that notification procedures exist with couriers, but agreed that the surge in e-commerce and parcel traffic is an emerging pressure point for Zimbabwe’s biosecurity system.
How Is Climate Change Turning Up The Pressure?
Threaded through Nyaruwata’s slides was a quiet but persistent theme: climate change is already reshaping the pest and disease map that Zimbabwe must navigate.
Rising temperatures, erratic and reduced rainfall, and more frequent droughts are creating conditions in which many pests and pathogens thrive. Warmer winters allow some insects to survive where they previously could not. Stressed plants are more vulnerable to infection. At the same time, climate shocks drive sudden surges in grain imports, which can stretch inspection capacity.
Participants linked recent El Niño cycles — which have brought harsh droughts to Zimbabwe — with more severe pest outbreaks in some districts. Regional projections point to around 2°C of warming by 2050. For plant health systems, that is not a distant scenario; it is a planning horizon that starts now.
The group discussed the need for emergency preparedness protocols tailored to rapid food import situations, when the pressure to clear ships or trucks can overshadow meticulous inspection. The IPPC’s Pest Emergency Preparedness (PEP) tool was highlighted as a practical framework for such planning.
Climate pressures are also amplifying problems already in the field. A study of smallholder maize across four agroecological zones in Zimbabwe found aflatoxin contamination in 52 percent of maize samples and fumonisin contamination in 89 percent. These mycotoxins, produced by fungi that flourish in hot, dry conditions and in poorly dried grain, are linked to liver cancer, oesophageal cancer and neural tube defects.
FFA Explainer:
Aflatoxins and fumonisins are toxic compounds produced by certain fungi that infect crops like maize and groundnuts. They can accumulate in grain during drought, poor drying or storage. Unlike many pests, they are invisible to the naked eye, and cooking does not remove them, which makes early prevention and testing essential.
Where Does Zimbabwe Need To Invest Next?
As the webinar drew towards its close, Nyaruwata laid out a roadmap that participants from government, research, farmer organisations and the private sector largely endorsed. The priorities she outlined align closely with Zimbabwe’s broader goals under NDS1, the African Union’s Agenda 2063 and the UN Sustainable Development Goals on zero hunger and good health.
The key areas she highlighted were:
- Laboratory modernisation and molecular diagnostics
Upgrading infrastructure and training to accelerate accurate pest and pathogen identification, support safe trade and underpin regional collaboration. This includes retaining skilled scientists, not just training them. - Digital surveillance systems
Replacing fragmented, paper-based reporting with integrated, real-time systems so that a suspicious pest report from a farmer in Uzumba can trigger swift investigation and, if needed, containment. - e-Phyto implementation at scale
Rolling out electronic phytosanitary certificates across all major export commodities, reducing costs for exporters and cutting delays at ports while improving traceability. - Regional coordination
Deepening practical cooperation through SADC, COMESA and the African Union — from harmonised SPS measures to shared surveillance data and joint early warning initiatives. - Emergency preparedness
Developing, documenting and practising protocols for pest incursions and large-scale food imports during climate or economic crises, including clear roles for local authorities and extension workers. - Awareness and behaviour change
Sustained campaigns aimed at travellers, farmers, transporters, seed companies and traders about the risks of moving plant material informally and the benefits of compliance. - Reliable, long-term funding
Securing predictable resources to run laboratories, retain skilled staff, maintain surveillance networks and respond to emergencies, instead of relying on short project cycles.
“The gaps we have identified are not gaps in knowledge,” Nyaruwata said. “We know what needs to be done. What is needed is sustained commitment — from government, from partners, from the private sector, and from the international community.”
What Does This Mean For Farmers In The Field?
For a communal farmer in Chiredzi trying to save seed, or a youth agripreneur exporting chillies from Bindura, much of what PQSI does is invisible. Yet the consequences reach straight into their lives.
When fall armyworm marches across a maize field in Murehwa, it illustrates what happens when an invader outruns the defences. When a citrus shipment from Mazowe clears Chinese ports without a single quarantine interception, it shows what is possible when those defences work.
Plant biosecurity also opens doors for women and youth. As Zimbabwe’s horticulture export sector grows — from citrus and blueberries to avocados and baby vegetables — there is rising demand for skilled technicians in diagnostics labs, inspectors at packhouses, and trained scouts in orchards. Those are jobs that can and should be filled by a new generation of Zimbabwean scientists and field officers.
At the same time, farmers’ voices must shape the system. Effective surveillance depends on farmers recognising unusual symptoms and feeling safe to report them. Stronger links between PQSI, extension officers and farmer organisations — from irrigation schemes in Matabeleland South to smallholder horticulture groups in Honde Valley — will determine how quickly Zimbabwe spots the next dangerous arrival.
Plant Biosecurity Is Not Optional
The International Day of Plant Health exists to concentrate attention, once a year, on the roots of food security. The webinar on 14 May 2026 did that and more. It showed a plant health system in Zimbabwe that is stretched but functioning, staffed by people who can list Latin species names with ease but remain grounded in what those names mean for a family’s sadza, a child’s nutrition, or a community’s export hopes.
Zimbabwe’s food security story is, at its core, a plant health story. The maize that fills silos in Lions Den, the tobacco that earns foreign currency in Karoi, the citrus and blueberries that are beginning to find their way into Asian markets — all of it depends on a phytosanitary system that can keep the worst threats out and manage the rest.
FAO puts it starkly: without plant health, there is no food security. On that May morning, as the Zoom call slowly emptied and participants returned to their labs, border posts and fields, one idea lingered. Plant biosecurity is not an optional technical add-on. For Zimbabwe, it is the quiet line between hunger and harvest.
This article is based on a webinar held on 14 May 2026 to commemorate the International Day of Plant Health, featuring a presentation by Primrose K Nyaruwata of the Plant Quarantine Services Institute of Zimbabwe.
For more on related topics, see fall armyworm management, aflatoxin control in maize and digital trade systems.
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