Environmental Engineering Reference
In-Depth Information
Classical biological control as we know it today grew as a means of addressing
major plant and insect problems affecting crop production. The potential to use
natural enemies for control was explored back in the 18
th
century when several
attempts were made across the globe to introduce predators for the control of
insect pests At this time and until about 1990, vertebrate predators were included
as potential control agents but most introductions involving these were ineffective
and had much worse side effects in terms of impacts on non-target species. A more
professional approach, factoring in specifi city of natural enemies and their likely
impact, started in the late 1880s by applied entomologists working in countries
such as the USA and Australia who were looking at ways of addressing major spe-
cies outbreaks affecting whole crop industries (see Debach 1974 and Simmonds
et al
. 1976 for reviews). At these times, invasive species were referred to as 'pests'.
h e fi rst documented examples of the international transfer of natural enemies
to control invasive species were in the 1870s when the predacious mite
Tyroglyphus
phylloxerae
was sent from the USA to France for use against grape phylloxera
(
Phylloxera vitufolia
), and the ladybird (
Coccinella undecimpunctata
), was des-
patched from the UK to New Zealand in an attempt to suppress invasive aphid
pests. Neither of these appeared to achieve successful control, although their estab-
lishment was confi rmed. However, momentum gathered, particularly in the USA,
for this invasive species management approach, which resulted in the fi rst great
successes in classical biological control in the 1880s—which established it as a
major method of pest control for invasive species. One major early success was the
project conducted against the scale (
Icerya purchasi
) which was fi rst recorded in
the late 1860s in northern California; within two decades, the insect had reached
pest status and was threatening the burgeoning citrus industry in southern part
of the state, as well as other horticultural crops. Correspondence with Australian
entomologists, ascertained that it was not a problem species in Australia, although
it was a serious problem in New Zealand. A period of exploration resulted in ship-
ments of a parasitic fl y,
Cryptochaetum iceryae,
and a ladybird,
Rodolia
(
Vedalia
)
cardinalis
, from Australia to California. h ese species were subsequently estab-
lished in 1888-89, and within a few years of release, all infestations in the State
were under control; the ladybird was considered to be the most important agent.
h e cost of the project has been estimated at around US$5000, with the benefi ts
to the citrus industry of California amounting to millions of dollars annually ever
since. Furthermore, it has been calculated that similar successes have been achieved
in more than 50 countries, with the Galapagos Islands of Ecuador being the most
recent recipient of the rodolia ladybirds.
h e importance of fungi as natural enemies of arthropods was realised at a very
early stage, encapsulated in the later statements by Petch (1925) 'h at such dis-
eases do kill off large numbers of insects periodically and so exercise a considerable
natural control is undoubted' and by Steinhaus (1949) 'Entomogenous fungi in
