Pest management - Ecological Applications: Toward a Sustainable World - page 140

understand the pros and cons of chemical pesticides, their diversity and varied modes of action
recognize that biological control agents (predators, parasites and pathogens) can be used to deal
with pests, but sometimes with adverse consequences for other species
realize that, like all natural populations, pests can evolve - there are many cases of evolution of
resistance, particularly to pesticides but also to other agents
conclude that effective pest control usually requires a range of measures to be used in concert to
maximize economic benefi t but minimize adverse effects - this is Integrated Pest Management
(IPM)

6.1 Introduction ' I don't think we did anything wrong - and I'd do the same thing again. ' Jenny is adamant.

She's a farmer in New Zealand and, like generations before her, she hates rabbits.
' You have to wonder why on earth they were shipped to New Zealand in the fi rst place -
something to do with making European settlements more like home. ' Like many exotic
species, the rabbits thrived and built up extraordinarily dense populations, compet-
ing with sheep for fodder and in some areas creating a wasteland. ' Our main weapons
against rabbits were shooting and poisoning but the expense involved was never-ending.
It is hardly surprising that the farming community was keen on a 'biological' solution -
the introduction of a disease that would bring down numbers and keep them down. ' A
proposal in 1993 to introduce myxomatosis, a viral disease specifi c to rabbits that
causes evident pain and a lingering death, was abandoned after 100,000 people
signed a petition. Then in 1995 Australia and New Zealand got together to assess
rabbit calicivirus disease as a suitable control agent. Experimentation was meant to
be confi ned to a small island off the Australian coast, but the virus escaped and
spread like wildfi re across the mainland, killing a large proportion of rabbits as it
moved through the landscape. The New Zealand farming community asked for the
disease to be imported to New Zealand but the government declined. Then in 1997,
farmers took things into their own hands. ' I had my ten minutes of fame when the TV
news showed me with a virus-rich concoction of minced rabbit organs in my fridge! ' Her
farming friends smiled at that, but you can imagine she received hate mail too.
' Environmentalists said that a disease only known in European rabbits might conceivably
spread to kiwis - can you believe that? '
Wherever in the world rabbit calicivirus has been deliberately introduced, or
arrived in rabbit meat, it has reduced populations by 50-90%, being particularly
effective in dry, warm areas. Baby rabbits develop immunity, and mortality may
decline with time or the population may follow a cycle of low and high densities.
However, there seems no doubt that agricultural productivity improved in parts of
New Zealand, at least in the short term.

6.1.1 One person's
pest, another
person's pet

Those worried about the introduction of rabbit calicivirus disease included pet
lovers, because domestic rabbits are derived from the European rabbit ( Oryctolagus
cuniculus ) and are therefore susceptible to the disease. In fact, it is by no means
unusual for one person's pest to be another person's 'pet'. There are fi shermen who
would like to cull burgeoning seal populations to protect their fi sh stocks, but others
feel just as strongly that seals should be protected at all costs. There are rabbiters
in the UK who cherish the domestic ferrets ( Mustela furo ) they use to chase rabbits
from their burrows into waiting nets. But ferrets were imported to New Zealand in