Overview
Exposure to the pest is reduced by ensuring that the commodity is geographically isolated from the pest.
- Examples include requirements that a Pest Free Production Site be located a minimum distance from any other site producing the same commodity, and that processing or storage facilities (e.g. grain storage) are located a minimum distance away from where the commodity is produced.
- Evaluating the efficacy of this measure requires knowledge of the biology of the pest, especially its dispersal ability, to support the extent of isolation. It is also important that the distribution of the pest is correctly delimited.
- Geographical isolation from areas of pest abundance can be considered during pest risk assessment. In limited contexts it can be proposed as a phytosanitary measure.
- Assurance can be achieved through labelling requirements that allow trace back, and provide further confirmation that the commodity was produced only at the approved locations.
Evidence to support efficacy
Evidence is needed to show that geographical isolation from identified areas of pest abundance will result in reduced pest prevalence, or pest absence, on the sites registered for trade. The biology of the pest, especially its dispersal ability and host range, will be an important consideration, as well as the characteristics of the landscape.
Applying the measure
How it is used
Geographical isolation of production or post-production activities from areas of pest abundance can be considered when undertaking a pest risk assessment. It has been suggested as a measure (e.g. ISPM 04, 36, and 38), but it is not commonly applied in practice. It is probably most relevant when assessing and managing the risk of movement from individual businesses, such as centralised packaging, processing or storage facilities where evidence of geographical isolation for pest populations is strong.
Use with other measures
Geographical isolation may be combined with Pest Free and Low Pest Prevalence Site measures to provide additional confidence in pest levels on the site.
Similar measures
This measure is similar to a buffer zone measure where spatial separation reduces the risk of infestation, but the separation is not actively managed in this case.
Assurance of correct implementation
Maps that delineate the proposed registered site (e.g. production site or processing facility) in relation to the location of potential pest populations may be required. There may be requirements for record-keeping to facilitate trace back, and provide further confirmation that the commodity was produced only at the approved locations. In practice, surveillance and monitoring of pest population levels on-site (Low Pest Prevalence Site measure) and in the surrounding area (buffer zone measure) may be required to verify that the pest prevalence is acceptably low.