David Hunter, Entomologist, Australian Plague Locust Commission
I obtained a B. Sc. and M. Sc. at Simon Fraser University in Vancouver
Canada, and then completed a Ph. D. at the University of Queensland in
Brisbane, Australia. After a period as a Lecturer at Ithaca Technical College
in Brisbane, I joined the Australian Plague Locust Commission, undertaking
research on aspects of the biology of locusts that aid their management.
The major research programs have been:
Elucidation of biological information that aids forecasting and locust
Migration: I found that provided vegetation contains some green, adults
of the Australian plague locust are able to accumulate the lipid required
as fuel for long distance migration. Locusts that have accumulated lipid
take off after sunset and climbing to a height of hundreds of metres, are
carried long distances by the prevailing winds. A cooperative project studying
migrations using radar continues.
Diapause: Eggs of the Australian plague locust enter diapause in autumn
and we have discovered that this diapause is a result of an increase in
the temperature threshold for development. The temperature threshold for
development is about 16oC during spring and summer but during
the decreasing day lengths of autumn, it increases to >26oC,
and embryos enter diapause.
Factors leading to outbreaks: The critical factors leading to outbreaks
for the three main locust species in Australia have been elucidated. These
critical factors form an important part of a decision support system that
models locust development and outbreaks. When outbreaks are forecast as
likely, a program of early intervention is intitiated where the first bands
and swarms that form during outbreaks are treated. The aim is to reduce
the rate of population increase, preventing locusts from reaching plague
Our research team has developed a program that has successfully prevented
locust plagues in Australia during the 1990ís. The methods used in Argentina
against Schistocerca cancellata during the 1960ís to the 1980ís were adapted
to Australian locusts, leading to the prevention of plagues of the three
main locust species in Australia. By intervening early, a major outbreak
of the Australian plague locust was suppressed and prevented from reaching
plague proportions between 1991 and 1994. In cooperation with the Queensland
Department of Natural Resources, major outbreaks of the spur throated locust,
which is similar to the Red locust in Africa, were suppressed in 1996 and
outbreaks of the migratory locust have been suppressed in a continuous
program lasting from 1996 to 1999.
These successful programs relied almost entirely on use of chemical insecticides
but to ensure continued success of plague prevention at a time of increasing
constraints on insecticide use, emphasis has shifted to testing of biological
alternatives. The fungus Metarhizium, which the LUBILOSA group has
found to be most promising, has been tested for several years in Australia.
During 1999, Metarhizium was used to suppress local populations
of the migratory locust and the aim is tests of field efficacy against
populations of other locust species so that this biological agent can form
part of a program of integrated management of all locust species in Australia.