PEST RISK ANALYSIS (PRA) TRAINING Group Exercises Manual

PEST RISK ANALYSIS TRAINING - GROUP EXERCISES MANUAL GROUP EXERCISE NO. 3.3
GROUP EXERCISE NO. 3.3 – POTENTIAL ECONOMIC CONSEQUENCES
A pest may have direct or indirect effects and these may be economic, environmental
or social. In a pest risk assessment, each effect is evaluated separately and then
combined in order to reach a conclusion on a pest’s overall potential consequences.
Requirements described in this step indicate the information which should be
assembled, and suggest levels of economic analysis that may be carried out using that
information in order to assess the various potential effects of the pest. Wherever
appropriate, quantitative data should be used, though qualitative data may also be
used. Consultation with an economist may be useful.
In order to estimate the potential economic importance of the pest, information should
be obtained from areas where the pest occurs naturally or has been introduced. This
information should be compared with the situation in the PRA area. Case histories
concerning comparable pests can usefully be considered. Use the information provided
to answer the following questions:
1. Direct economic effects
• What are the known or potential host plants, including those in the field,
under protected cultivation, or growing in the wild (generate a list)? Are any
of the hosts of economic importance? If so, provide data to show how much
importance.
• What are the types, amount and frequency of damage caused by the pest? Are
some host species more susceptible than others?
• Does the pest cause crop losses, in yield and quality? If so, how much? What
revenue losses can reasonably be expected?
• Are there other biotic factors (e.g. adaptability and virulence of the pest) that
may affect damage and losses? If yes, list them.
• Are there abiotic factors (e.g. climate) that may affect damage and losses? If
yes, list them.
• What is the pest’s rate of reproduction and spread?
• What measures exist for control of the pest, and what is their efficacy and
cost?
• What effect might the pest have on existing production practices in the PRA
area? Consider changes in production methods and associated costs.
• Would presence of the pest necessitate additional costs over those already
incurred in production of the commodity? If so, what are they?
For each of the potential hosts, the total area of the crop and area potentially
endangered should be estimated in relation to the elements given above. Note also
that economic consequences are expressed over time, and may be felt in one year,
several years, or over an indeterminate period. Various scenarios should be
considered.
Using the information provided, describe and estimate the direct economic effects of
the pest if it were to be introduced and spread? If possible, predict the time period
over which these effects would be felt.
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