China believes it has hit on a way of killing two birds with one stone in its battle against a devastating plague of locusts.

There are plans to release thousands of ducks into infested fields near Beijing, where the density of locusts is estimated to be as high as 5,000 per square metre.

Ducks are the best way to get rid of locusts because they have such a big appetite

Xiao Hongwei locust station official

Experts say the ducks, with their voracious appetites, are ideal for controlling the crop-eating insects but there is little in it for the ducks.

Come the end of their important mission, most will wind up in roast duck restaurants wrapped in pancakes with spring onions and plum sauce.

The scheme is nothing new, with a similar initiative involving both ducks and chickens launched two years ago in Xinjiang province.

A good duck can devour up to 400 locusts a day

But a long spell of dry weather and the degradation of the environment in some regions have encouraged the insects this year in the northern provinces.

The government has allocated nearly 50 million yuan ($6m) to help eradicate the locusts.

Crop-duster aircraft and about 100,000 personnel on the ground are preparing for a major drive against them before they start to spread, as expected.

An official at the Manasi locust station in the north-west confirmed that about 4,000 ducks would be released into the surrounding fields.

"Ducks are the best way to get rid of locusts because they have such a big appetite," Xiao Hongwei told Reuters news agency.

"After two or three months, they typically weigh around two kilos and can be sold to markets and roast duck restaurants."