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Michael J. Firko and Edward V. Podleckis
nationally accepted criteria (Hopper 1995; FAO 1996) and is based largely on the
presence or absence of the pest in the area at risk. Because not all quarantine pests
in the export area can reasonably be expected to accompany the commodity, some
quarantine pests may not be considered in detail in the risk assessments. For
example, consider a soil-dwelling nematode that is a pest of orange trees in the
production area: if only fresh fruit—which must be free of all leaves, stems, and
other plant parts—are to be moved, there is little risk that the soil nematode will
be moved.
Note that the hazard considered is human-assisted spread of pest organisms to
areas outside of their current ecological range. Although organisms spread naturally, our risk assessments typically deal only with human-assisted spread because
the assessments are prepared to support decisions about regulated activities.
USDA sometimes conducts assessments that focus on the persistent problem of
introductions via smuggling of agricultural commodities. Occasionally, natural
spread is considered along with human-assisted spread. Assessments are also
limited by the scope of the regulatory authority. Some types of organisms, such as
mammals, birds, reptiles, many spiders, and scorpions, fall under the jurisdiction
of other federal agencies regardless of whether they can be considered plant pests.
The regulatory focus is on human activities that may disseminate invertebrate
animals and plant pathogens with the potential to act as direct or indirect plant
pests.
How Bad Would It Be?
This question can be restated as “What are the consequences?” We consider the
biological potential of the quarantine pests to have negative economic (e.g.,
lowering yields or decreasing the value of the crop) and environmental impacts in
the area at risk. We also consider the pest’s potential to cause direct environmental
impacts or impacts on species listed as endangered or threatened. We do not
consider quantitative measures of the consequences of plant pest introductions.
Although risk managers typically are informed of the economic ramifications of
pest introductions, focus on monetary values is outside the scope of biological risk
assessments. Although we and other biologists work with economists conducting
monetary assessments, the methods and tools are the domain of economics. Biological risk assessments use qualitative methods to consider the biological potential of pests to cause economic damage.
What Is the Likelihood That It Will Happen?
For our assessments, this question becomes “What is the likelihood that nonindigenous plant pests will be introduced into the area at risk as a result of the
regulated activity?” Most USDA decisions regarding movement of agricultural
commodities are based on qualitative risk assessments in which estimates of risk
are expressed in terms such as high or low. But increasingly, quantitative approaches for estimating the likelihood of “bad events” such as pest introductions
Michael J. Firko and Edward V. Podleckis
nationally accepted criteria (Hopper 1995; FAO 1996) and is based largely on the
presence or absence of the pest in the area at risk. Because not all quarantine pests
in the export area can reasonably be expected to accompany the commodity, some
quarantine pests may not be considered in detail in the risk assessments. For
example, consider a soil-dwelling nematode that is a pest of orange trees in the
production area: if only fresh fruit—which must be free of all leaves, stems, and
other plant parts—are to be moved, there is little risk that the soil nematode will
be moved.
Note that the hazard considered is human-assisted spread of pest organisms to
areas outside of their current ecological range. Although organisms spread naturally, our risk assessments typically deal only with human-assisted spread because
the assessments are prepared to support decisions about regulated activities.
USDA sometimes conducts assessments that focus on the persistent problem of
introductions via smuggling of agricultural commodities. Occasionally, natural
spread is considered along with human-assisted spread. Assessments are also
limited by the scope of the regulatory authority. Some types of organisms, such as
mammals, birds, reptiles, many spiders, and scorpions, fall under the jurisdiction
of other federal agencies regardless of whether they can be considered plant pests.
The regulatory focus is on human activities that may disseminate invertebrate
animals and plant pathogens with the potential to act as direct or indirect plant
pests.
How Bad Would It Be?
This question can be restated as “What are the consequences?” We consider the
biological potential of the quarantine pests to have negative economic (e.g.,
lowering yields or decreasing the value of the crop) and environmental impacts in
the area at risk. We also consider the pest’s potential to cause direct environmental
impacts or impacts on species listed as endangered or threatened. We do not
consider quantitative measures of the consequences of plant pest introductions.
Although risk managers typically are informed of the economic ramifications of
pest introductions, focus on monetary values is outside the scope of biological risk
assessments. Although we and other biologists work with economists conducting
monetary assessments, the methods and tools are the domain of economics. Biological risk assessments use qualitative methods to consider the biological potential of pests to cause economic damage.
What Is the Likelihood That It Will Happen?
For our assessments, this question becomes “What is the likelihood that nonindigenous plant pests will be introduced into the area at risk as a result of the
regulated activity?” Most USDA decisions regarding movement of agricultural
commodities are based on qualitative risk assessments in which estimates of risk
are expressed in terms such as high or low. But increasingly, quantitative approaches for estimating the likelihood of “bad events” such as pest introductions