Sticky snakeroot, Mexican devil or Crofton weed – call it what you want – since the early 1900s this weed has been causing grief in Australia. But now the release of a new biological control agent brings some hope.
The tenacious and troublesome Crofton weed (Ageratina adenophora), as it is commonly known, has been running rampant in eastern coastal Australia since it ‘escaped’ from being an ornamental plant in Sydney gardens.
It has taken hold on Lord Howe Island, a World Heritage Area, where it is found mainly in non-accessible areas, making manual removal and herbicide control impractical.
Crofton weed is a serious environmental weed that has invaded agricultural lands as well as 150 reserves in NSW managed by the National Parks and Wildlife Service (NPWS). It reduces the ecological value of bush land but also affects grazing land on farms by diminishing their carrying capacity.
The weed spread rapidly during the 1940s and 1950s creating dense infestations, particularly along waterways and disturbed areas, inhibiting native regeneration and threatening several vulnerable or endangered native species and communities, including those on Lord Howe Island.
The new biological control agent is a rust fungus that originates from Mexico (where Crofton weed is native) and works by infecting the young leaves and stems of the plant, stunting development and disrupting its ability to reproduce.
Dr Louise Morin, plant pathologist from CSIRO’s Biosecurity Flagship, is leading the Crofton weed rust fungus release program.
“The release of this fungus in Australia is exciting because it could make a big difference in the management of Crofton weed populations,