Plant quarantine and phytosanitary certification
How countries keep out new crop pests: the IPPC and its standards, pest risk analysis, phytosanitary certificates, treatments, inspection and response.
On this page
The most damaging pests and diseases in many countries are not native. They arrived on planting material, in grain and fruit, in wooden packaging, on vehicles and in travellers' bags, and found crops with no resistance and no natural enemies. Fall armyworm reached Africa in 2016 and spread across most of the continent and into Asia within a few years; Xylella fastidiosa appeared in olive groves in southern Italy in 2013; the TR4 strain of Fusarium wilt of banana has spread from Asia to the Middle East, Africa and Latin America.
Plant quarantine, or plant biosecurity, is the system of rules and actions that tries to stop such pests moving between countries and regions. It is a core subject for plant protection officers and a standard topic in plant pathology and entomology examinations.
The international framework
- The International Plant Protection Convention (IPPC), a treaty first adopted in 1951 and administered through FAO, with more than 180 contracting parties. It aims to protect plants, agriculture and the environment from pests, while avoiding unnecessary barriers to trade.
- International Standards for Phytosanitary Measures (ISPMs), adopted under the IPPC, set out how countries should carry out pest risk analysis, inspection, certification, treatments and surveillance.
- The WTO Agreement on Sanitary and Phytosanitary Measures (SPS Agreement, 1995) requires that phytosanitary measures be based on science and risk assessment, not be more trade-restrictive than necessary, and be consistent; it names the IPPC as the standard-setting body for plant health.
- National Plant Protection Organizations (NPPOs) carry out the work in each country, and Regional Plant Protection Organizations (such as EPPO, NAPPO, the Asia and Pacific Plant Protection Commission and others) coordinate within regions.
Key definitions
The IPPC glossary (ISPM 5) defines terms used everywhere:
- Pest: any species, strain or biotype of plant, animal or pathogenic agent injurious to plants or plant products.
- Quarantine pest: a pest of potential economic importance to the area endangered thereby and not yet present there, or present but not widely distributed and being officially controlled.
- Regulated non-quarantine pest: a pest already widespread but whose presence in plants for planting has an unacceptable economic impact, so it is regulated in planting material (for example virus diseases in seed potatoes).
- Phytosanitary measure: any legislation, regulation or official procedure intended to prevent the introduction or spread of quarantine pests or limit the impact of regulated non-quarantine pests.
Pest risk analysis
Measures must be justified by pest risk analysis (PRA), set out in ISPM 2 and ISPM 11. It has three stages:
- Initiation: identify the pest or the pathway (a commodity, such as fresh mangoes from a given origin) that may need regulating.
- Risk assessment: is the pest absent or under control here? How likely is entry with the pathway, establishment (suitable hosts and climate), and spread? What would the economic, environmental and social consequences be?
- Risk management: choose measures that reduce the risk to an acceptable level, from the least trade-restrictive options that work.
The layers of protection
Before the border
- Import conditions for each commodity and origin, based on PRA.
- Pest-free areas, pest-free places of production and areas of low pest prevalence (ISPM 4, 10 and 22), recognised by the importing country.
- Treatments, for example:
- Heat treatment of wood packaging (ISPM 15): pallets and crates must be heat-treated to at least 56 °C at the core for 30 minutes (or fumigated or treated by other approved methods) and stamped with the IPPC mark, to stop wood-boring insects such as longhorn beetles and the pine wood nematode.
- Cold treatment of fruit against fruit flies, holding fruit at low temperatures (around 1–2 °C) for a specified number of days.
- Vapour heat, hot water and irradiation treatments for fruit and vegetables; fumigation of some commodities.
- Systems approaches: combining several measures (resistant hosts, field control, harvest timing, packing-house inspection), none sufficient alone.
- Phytosanitary certificate (ISPM 12): issued by the exporting country's NPPO, certifying that the consignment was inspected and meets the importing country's requirements.
At the border
- Checking documents and certificates.
- Inspecting and sampling consignments, with laboratory diagnosis of suspect material.
- Actions on non-compliance: treatment, re-export, destruction, and notification to the exporting country.
- Controls on passengers' baggage and mail, a common pathway for planting material and fruit.
How many units must be inspected?
An inspector wants 95 per cent confidence of detecting an infestation if at least 1 per cent of fruits in a large consignment are infested. For a large lot, the number of units to sample is approximately:
n = ln(1 − confidence) ⁄ ln(1 − infestation level) = ln(0.05) ⁄ ln(0.99) = −2.996 ⁄ −0.01005 ≈ 298 fruits.
To detect 0.1 per cent infestation with the same confidence needs about 2,994 fruits. This is why inspection alone cannot guarantee pest freedom at very low infestation levels, and why treatments and pest-free areas are used before the border. (ISPM 31 sets out sampling methods for consignments.)
After the border
- Post-entry quarantine for high-risk planting material, grown under observation in secure facilities before release.
- Surveillance (ISPM 6): general surveillance by farmers and the public, and specific surveys with traps and inspections for high-risk pests, such as fruit fly trapping grids around ports.
- Emergency response: if a quarantine pest is found, delimiting surveys, then eradication where feasible (destroying infested plants, treatments, movement restrictions), or containment and management if eradication fails.
- Domestic quarantine: restricting movement of plant material between regions of a country where a pest is present in some regions and not others.
Examples that shaped plant quarantine
- Potato late blight in mid-nineteenth-century Europe and the resulting Irish famine showed how one introduced pathogen could devastate a food system.
- Grape phylloxera, an aphid-like insect from North America, destroyed most European vineyards in the late nineteenth century and led to some of the first international plant protection agreements; it was overcome by grafting onto resistant American rootstocks.
- Citrus greening (huanglongbing), spread by psyllids and infected budwood, has severely damaged citrus industries in Asia, Africa and the Americas.
- Fall armyworm's rapid spread after 2016 showed the limits of border controls for strong-flying pests and the importance of early warning and preparedness.
Key points
- Plant quarantine aims to prevent the introduction and spread of pests between countries and regions.
- The IPPC (1951, FAO) and its ISPMs set the international standards; the WTO SPS Agreement requires measures to be science-based and not unnecessarily restrictive.
- A quarantine pest is absent from an area, or present but not widely distributed and officially controlled; regulated non-quarantine pests matter in planting material.
- Pest risk analysis: initiation, risk assessment (entry, establishment, spread, consequences), risk management.
- Layers: pre-border (pest-free areas, treatments such as ISPM 15 heat treatment, certificates), border (inspection, sampling), post-border (post-entry quarantine, surveillance, eradication or containment).
- Detecting 1 per cent infestation with 95 per cent confidence needs about 300 units sampled.
What the exams ask
- School-leaving and entrance papers: the purpose of quarantine, the meaning of a quarantine pest, and examples of introduced pests.
- Degree and research-fellowship entrances: the IPPC, ISPMs, SPS Agreement, pest risk analysis, phytosanitary certificates, treatments and post-entry quarantine.
- Plant protection officer and civil-service examinations: designing import conditions, surveillance and emergency response, ISPM 15, inspection sampling and domestic quarantine.
Described in general terms: the kind of examination, not a past paper. Laisha never reproduces exam questions.
Questions people ask
Why can't travellers bring fruit or plants home?
Fruit, seeds, cuttings and soil can carry insects, pathogens and nematodes that are absent from the destination. A single infested fruit can start an outbreak of fruit flies or a new plant disease, so many countries prohibit or restrict them.
Is quarantine just a trade barrier?
It should not be. The SPS Agreement requires measures to be based on scientific risk assessment and to be no more restrictive than necessary. Disputes over unjustified measures can be taken to the WTO.
What happens if a quarantine pest is found?
The plant protection authority surveys to find how far it has spread, then tries to eradicate it if feasible, using destruction of infested plants, treatments and movement restrictions. If eradication fails, it moves to containment and long-term management.
Sources
- IPPC Secretariat. International Plant Protection Convention (1997 revised text) and International Standards for Phytosanitary Measures, including ISPM 2, 4, 5, 6, 11, 12, 15 and 31. FAO, Rome.
- World Trade Organization. Agreement on the Application of Sanitary and Phytosanitary Measures. WTO, 1995.
- Ebbels, D. L. Principles of Plant Health and Quarantine. CABI, 2003.
- Day, R. et al. "Fall armyworm: impacts and implications for Africa." Outlooks on Pest Management 28, 196–201 (2017).
- Ploetz, R. C. "Fusarium wilt of banana." Phytopathology 105, 1512–1521 (2015).
More in plant pathology
Discussion
Questions, corrections and notes from readers on this article. Every comment is checked before it appears: keep it on the topic, and do not share phone numbers, links or contact details.