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In
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Eradication
Eradication
of newly introduced pests
Eradication
usually goes hand-in-hand with quarantine. It’s based on the
assumption that small, localized infestations that have broken through
quarantines have to be exterminated before they become established
and render the quarantine useless. Success in eradicating new infestations
depends on several factors:
- Sensitive
detection methods that can detect low populations of the pest.
- Ability
to mobilize the eradication effort quickly. (The population must
be hit while it is still small and localized.)
- Effective
eradication methods that can eliminate a population.
- Thorough
mop-up (eradicating the last individual).
- Effective
barriers to reintroduction. Natural physical barriers and quarantine
must keep new introductions to a trickle.
What are the costs and benefits of
quarantine and eradication? They must be weighed against those of
allowing the pest to become established. Think about
- the
frequency of reintroduction and the costs of consequent eradication
efforts;
- the
environmental costs of periodic, intense eradication campaigns;
- the
long-term environmental costs of managing a pest once it is established;
- who
benefits economically. Governmental agencies (and thus the taxpayers)
typically bear the costs of quarantine and eradication, yet the
benefits accrue initially to the growers and then, perhaps, to
the consumers.
Eradication
of established pests
Many
people advocate eradicating introduced pests that have become well
adapted over a long period of time, or even native pests. Eradication
has been attempted for the boll weevil, screwworm fly, fire ants,
witchweed, and golden nematode.
Eradication
of established pests is very controversial. Advocates and opponents
of the various eradication programs have become strongly polarized.
Arguments
for eradication:
- Eradication
of many species is now feasible because of new technological advances
(e.g., sterile insect release, pheromone traps, etc.).
- The
total cost of the pest control program (routine sprays over a
period of years) will be reduced.
- The
long-term environmental risks of repeated insecticide sprays outweigh
the short-term environmental risk of an intensive eradication
effort.
- Eradicating
a species that requires high pesticide inputs enables biological
control of the other species in the pest complex.
Arguments
against eradication:
- Eradication
efforts have been successful only for small outbreaks of newly
introduced pests.
- Eradication
requires unacceptably high environmental pollution; nontarget
organisms are affected by the pesticides used during eradication.
- Removing
a particular species from an ecosystem might have far-reaching
effects on the complex relationships among other organisms in
the ecosystem.
- Eradication
programs are being attempted without adequate understanding of
pest biology.
To
blunt the criticism, eradication proponents have shifted the names
of their programs (and by implication, their objectives) from "eradication"
to "area-wide suppression."
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