Australia's wine crop is in danger from a swarm of 100 billion locusts that are set to ravage vineyards.The plague is expected to be the worst in several decades as a wet southern summer has produced ideal breeding conditions.A big locust outbreak has already attacked New South Wales and Western Australia's wheatbelt.The Plague Locust Commission estimates that the insects could cause A$200m damage to cereal, vegetable and wine crops in the eastern states.David Asia-Pacific correspondent