Measure category: pest avoidance

Measures in this category include:

• Restricted to poor pest habitat
• Limit seasonal overlap
• Limit exposure time to pest
• Isolation from hot spots
• Habitat manipulation

Note that this resource is a working draft, which is currently being reviewed and updated in collaboration with biosecurity specialists.

Overview of measure category

Pest avoidance is achieved by minimising the overlap of vulnerable commodity stages with pests in space and time. Avoidance can be partial or complete.

Required proof of efficacy

Evidence (knowledge of biology, empirical data or modelling) is required to demonstrate that the reduction in overlap between pest and susceptible stages is sufficient. 

How these measures are certified

Depends on the measure.

How these measures are used

Pest avoidance measures can apply to production and post-production (e.g. to reduce the risk of secondary infestation). Pest avoidance can be achieved by applying measures to the whole production system (e.g. restricting production to poor pest habitats or times of the year when pest abundance is low) or to processes within the supply chain (e.g. limiting the time that the commodity is exposed to pests). Where they apply across the industry (e.g. the commodity only matures at times when pests are seasonally rare), pest avoidance measures may contribute to PRA rather than becoming a phytosanitary measure.

Relationship with other measures

Pest avoidance measures limit the a priori risk of the commodity or carrier being exposed to the pest. Exposure risk is often reduced further through inclusion of additional, dependent, pest freedom or low pest prevalence, pest management or pest exclusion measures.

Consignment stages where these measures can be applied

Measures	Production	Post-production	Post-border
Restricted to poor pest habitat	Yes	Yes	No
Limit seasonal overlap	Yes	Yes	No
Limit exposure time to pest	Yes	Yes	No
Isolation from hot spots	Yes	Yes	No
Habitat manipulation	Yes	Yes	No

Measures in detail: pest avoidance

Measure	Required proof of efficacy	How the measure is certified	How the measure is used	Relationship to other measures
Restricted to poor pest habitat Exposure to pests is limited by restricting production or post-production to places where poor pest habitat limits pest abundance.	Comparative surveillance data can be used to provide confidence that the habitat is poor. Knowledge of the biology, often formalised through modelling (e.g. phenological modelling to show generations per year), can also be used. Combining the two can provide confidence that the habitat will be poor (and pest abundance low) despite inter-year environmental variation.	Protocol only allows registered sites within the agreed region to be registered.	Contributes to pest risk assessment, especially where the production only occurs in poor habitat. It can be used as a measure to, for example, limit production to areas of poor pest habitat. Aspects of habitat that may be considered include climate or microclimate, production conditions (e.g. what substrate production is in), the availability of alternative or obligatory hosts in the area, and the presence of natural enemies.	Poor habitat is often combined with limited seasonal overlap. There may be less requirement for other measures such as pest monitoring with corrective action or pest management in areas where habitat is poor for the pest.
Limit seasonal overlap Exposure to pests is limited temporally by ensuring that the period when the host or carrier is susceptible has limited or no overlap with when physiological and environmental conditions allow the pest to be active or infective	Evidence of efficacy is similar to that for poor pest habitat. The phenology of both the host/carrier and pest, and any overlap between the two, can vary considerably between years and across production regions. This needs to be considered in any analyses.	Evidence that activities only occur during the prescribed times.	Production (e.g. harvest times) or post-production (e.g. storage times) are restricted to low risk times. Times can be fixed or calibrated to environmental cues where seasonal overlap is varies between years and locations. Timing normally relates to time of year, but could also be time of day (e.g. for dispersing pests that post a risk during processing).	Limited seasonal overlap is often combined with poor habitat. There may be less requirement for other measures such as pest monitoring with corrective action or pest management in areas where limited seasonal overlap can be demonstrated
Limit exposure time to pest The duration of time the commodity or carrier is exposed to the pest is restricted.	Risk will be a function of exposure time, pest abundance and host susceptibility. Evidence may be required to demonstrate that risk is actually elevated during the period when the measure applies (e.g. when fruit are picked vs on the tree), and that the measures will sufficiently address that.	Relevant production and post-production processes need to be auditable.	Most often applies to post-production steps where there is a heightened risk of exposure, such from point of harvest to a secure location, or where commodities are stored outside (e.g. timber). It can be applied during production, for example limiting how long mature fruit can remain on the tree prior to harvest, or the age of nursery plants for sale. Exposure time is typically considered during the PRA, with a phytosanitary measure only added where limiting exposure time is not standard industry practice.	Commonly combined, or replaced, by pest exclusion measures.
Isolation from hot spots Geographic isolation from potential sources of the pest.	Evidence required to support the nature and extent of isolation. Pest biology and environmental conditions will be important considerations.	Demonstrate required isolation has been achieved	Geographical isolation of production or post-production activities from hot spots has been suggested as a measure (ISPM4, 36, 38), but we’ve found no examples of it being a requirement.	Differs from “maintain buffer zone” in that separation is not actively maintained.
Habitat manipulation Modify the habitat to make it less suitable or attractive to the pest.	Demonstration that the habitat manipulation reduces pest abundance in production or post-production sites to a sufficient extent, through making it less attractive or less suitable for maintenance of pest population.	Manipulations auditable (e.g. through environmental logs), and able to be validated through in-field inspections.	Climate control, managing free water and altering lighting can all affect habitat suitability (e.g. of glasshouses or storage facilities) or attractiveness (e.g. for dispersing insects around shipping). This can be factored into PRAs or, less commonly, be a regulatory requirement.	Rarely used.

Key references

• Key references will be determined through consultation with biosecurity specialists and added here in the coming months.