Environmental Engineering Reference
In-Depth Information
the agents showed high specifi city, based on the studies to date, to warrant release
as a classical agent (Cock and Seier 2007). What, therefore, are the options? The
programme had a fi nite time frame (2002-05) and the relatively limited budget
had to be split between the various disciplines. Closer analysis of the biological
control project, and comparison with recent, successful, weed biological control
projects, showed that more funding and considerably more time (5-10 years) are
required to complete risk assessments of potential agents. In conclusion, there-
fore, insuffi cient time and resources were allocated to clarifying the ambiguous
and anomalous results of the host-range tests and, consequently, the potential
of this pathogen, and other agents, for the classical biological control of giant
hogweed.
h e term 'pathophobia' was coined to draw attention to the slow progress and
lack of funding interest in applied weed pathology, despite the early successes in the
1970s of this still-developing fi eld of invasive species management (Freeman and
Charudattan 1985). h e use of pathogens in biological control, and, in particular
of fungal pathogens of invasive plants, has proven to especially problematic since
the risks involved have invariably been judged to be unacceptable, founded not
on scientifi c pest risk assessments but more on emotive, historical narratives on
plant disease outbreaks which show what coevolved pathogens can do once they
catch-up with their crop hosts in exotic situations However, on the positive side,
they also demonstrate just how eff ective coevolved natural enemies can be for the
sustainable management of alien plants which have become invasive in their new
habitats.
h e introspective capacity for self-analysis and regulation has, fortunately,
been a feature of biological control practitioners especially relating to the prin-
ciples and safe practice of their discipline (Marohasy 1996; McFadyen 1998).
Data on weed biological control projects involving insect agents has been exam-
ined and it was concluded that, despite the intercontinental movement of over
600 insect species, there are few documented cases of non-target eff ects: all were
considered to be predictable behavioural responses rather than the purported and
more evocative 'host shift or jump'. h e inherent safety and genetic stability of
these coevolved agents was stressed (Marohasy 1996). Similarly, the perform-
ances of 26 fungal pathogens used as classical biological control agents for the
management of invasive plants has been analysed (Barton 2004). h ere were no
instances of non-target eff ects and it was even concluded that the central plank of
risk assessment—host-range testing—was, in fact, over-rigorous since a number
of pathogens which had demonstrated extended host ranges in the greenhouse
situation, but, nevertheless, still cleared and released based on risk:benefi t ana-
lyses, were never recorded from these same species in the fi eld. In the case of the
biological control of insects, an analysis showed that there is only data relating to
 
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