PREDATOR ON THE PROWL
Aphids, the scourge of home gardeners and a problem in horticulture and agriculture, may be less of a problem with the discovery of a new ladybird for which aphids are a prime food source.
Principal entomologist with the Department of Primary Industries' Agency for Food and Fibre Sciences, Bernie Franzmann, said that the new ladybird belied its popular fairytale image by being an aggressive predator capable of consuming large numbers of aphids.
The ladybird, Hippodamia variegata, also known as variegated ladybird in the United States, was different to the variable ladybird already found in Australia.
To avoid confusion, Mr. Franzmann said that he was calling the new discovery the 'spotted amber ladybird'.
He said: "The spotted amber ladybird is well-known overseas as a voracious feeder, playing an important role in the control of aphids in a wide variety of crops.
"While it has been observed eating the corn aphid on sorghum in Australia, internationally it feeds on a range of aphids, including cotton aphids in China, aphids on potatoes in Poland and aphids on wheat in South Africa. It is also found on peanuts, lucerne and beans, and the prospects are good for its being beneficial for any other plants affected by aphids."
Mr Franzmann said that he did not know how the ladybird arrived in Australia, but he had first observed it in the Lockyer Valley, and it had since been seen in sorghum crops at Warwick and near Dalby.
He said that the original home of the spotted amber ladybird was Europe, Russia and China. "Because of its ability to eat large numbers of damaging aphids, there have been attempts to introduce it into the United States since the 1950s," he said. "Success was finally achieved in the late 1980s.
"The ladybird is able to quickly spread, and its accidental arrival in South Africa in 1967 saw it well-established within a few years throughout the country, where it is the most important predator of the Russian wheat aphid."
Mr Franzmann said that the ladybird would be a useful addition to integrated pest management practices, which promoted the use of natural predators for pest control instead of using chemicals.
"The aphid can be a particularly problematic insect because, in many instances, it is uneconomic to attempt chemical control in broadacre situations," he said.
"The spotted amber ladybird will play an important role in maintaining an environmentally sustainable production system."
Further information: Department of Primary Industries Public Affairs, PO Box 102 Toowoomba Qld.
DATE: August 2002
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