Ryegrass, fire ants and feral cats: major Australian study identifies costliest pests in past 60 years

The study identifies each state's most economically damaging species and warns costs could rise further without investment

Invasive plants, animals and diseases have cost Australia at least $390bn in damages and management costs over the past 60 years, according to research that has painted the most accurate picture yet of the economic burden of these invaders.

Feral cats are the costliest of the hundreds of individual species studied, accounting for just over $10bn in damages and management expenses. Rodents, pigs and rabbits came close behind.