When Australian farmer Tony Knight first saw a purple-flowering plant growing across the bushfire-scarred terrain where his sheep grazed, his first thought was that it looked like “good stock feed”. But the “pleasant-looking plant” was far from the nutritious food his livestock needed after their paddocks were razed bare by the fires that swept through the northwest region of New South Wales state last year.
Instead, the native weed known as “the Darling Pea” contained a toxin that affected the sheep’s nervous systems, killing hundreds by triggering mental and physical deterioration. “To start with, they will do quite well when they first get on to it and their condition will pick up”, Knight said from his farm near the town of Coonabarabran.
“But once it gets them addicted, it’s just a drug, it goes from becoming their best friend to their worst enemy.”
Knight said he had lost almost 100 merino sheep out of an 800-strong flock to the noxious pea in recent months, while his sister-in-law Louise, who lives on the farm next door, said 800 of her sheep from a total of 14 000 had died after eating the plant.
A confluence of events enabled the outbreak, with the weed growing in an area where bushfires had wiped out its competition. The destruction of fences during the bushfires, which devastated 54 000Ha of land, meant it was difficult to rotate the livestock on to non-affected fields as the animals roamed the mountainous terrain, chewing the weed as they went.