Billions of locusts threaten Australia

By Rebecca Courtney 14 July 2010
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Vast areas of Victoria and New South Wales are braced for the worst plague in 30 years.

INLAND AREAS OF VICTORIA, New South Wales, South Australia and Queensland are bracing themselves for the worst locust plague in 30 years, set to start when eggs begin to hatch in August.

Surveillance of buried egg-beds has revealed “egg densities of up to 10,000 per square metre in some areas,” says Chris Adriaansen, Director of the Australian Plague Locust Commission (APLC), based in Canberra. “However, for every egg-bed you know of, or can find to survey, there will be another dozen which remain unknown until they hatch.”

Speaking today at an online briefing arranged by the Australian Science Media Centre, Chris said that the coming plague is “the result of the perfect storm” which could see more than 15,000 nymphs of the Australian plague locust (Chortoicetes terminifera) per square metre.

High rainfall

The occurrence of high summer and autumn rainfall provided an ideal environment for extensive breeding and egg-laying. Normally, each generation has only one batch of eggs, but this year has seen “two, three, or even four batches,” he says.

Swarms of plague locusts can migrate hundreds of kilometres overnight and strip vegetation right down to the ground, says Associate Professor Greg Sword from the University of Sydney. Their regular diet is cereal, grasses and grain, but swarming locusts and marching wingless nymphs will destroy vegetable and canola crops and any other food source they can find, says Chris. These sources can include gardens, city parks and national parks.

Command centres are being established for locust surveillance to help the States prepare. There are 14 centres permanently in place in New South Wales, which currently deal with a variety of issues, including plagues of locusts and mice.

The density of eggs is particularly extensive across wide areas of Victoria, where farmers may have to face a plague on a scale not seen in 75 years. The Victorian Government is investing $43.5 million which includes a 100 per cent rebate to farmers for the cost of locust-spraying chemicals, while South Australia has allocated $12 million to combat the threat. 

Hit to farming yields

Victorian Premier John Brumby says the funding will allow farmers to “buy the chemicals needed now to treat locust hoppers [nymphs], ensuring that when the locusts come they can be dealt with quickly.”

Chris was wary of making guesses at this stage of the full scale of potential damage to farming yields, but authorities warn the impending plague could cause billions of dollars of damage to agriculture. A statement from the Victorian Premier’s office suggest that worst case scenarios could result in 35 per cent losses of cereals, 30 per cent losses in horticulture and a 20 per cent loss of profits on dairy and other livestock industries. 

Previous locust plagues in Victoria have seen the delay of the Melbourne Cup and the Boxing Day cricket test match, and swarming locusts have even been known to cause traffic accidents and ground aeroplanes.

Little can be done to prevent eggs from hatching, but newly hatched nymphs are easy to kill with insecticide. Once they develop wings and become more mobile they are extremely hard to control.

Hatching will begin in the warmer areas of Queensland and New South Wales from August, while cooler regions will see eggs hatching in September and October. Landowners are urged to work closely with their community and government to monitor and manage the locust threat as spring nears and they begin to hatch.