A NOXIOUS weed, boosted by ideal growing conditions and affecting properties in the Gawler area, is being tackled with the release of moths.
The horehound plume moth was first released 20 years ago and has just been re-released north of Gawler, as an effective biological control against horehound weed.
Horehound is an introduced perennial herb, traditionally used to make beer, which can grow out of control if not managed, invading rural properties and contaminating the meat, milk and wool of livestock that eat it.
Natural Resources Adelaide and Mount Lofty Ranges (AMLR) District Officer David Hughes said this year’s generous rainfall has created a perfect environment for the pest plant to thrive.
“We’ve been aiming to reduce the weed using one of the best weapons, a natural biocontrol called horehound plume moth,” Mr Hughes said.
“Some farmers have said the moth is so effective that when it goes to work, it’s like a thousand sheep have come in and eaten the weed back to the roots.”
Natural Resources AMLR was recently asked to assist landowners with an infestation of horehound at a Rosedale property, with officers from the Gawler Natural Resource Centre applying about 60 caterpillars of the horehound plume moth, collected from bushes around the district, to a five-hectare area.
The caterpillar of the moth will only feed on horehound and, when active, can heavily reduce the seeding capability of the pest plant and reduce the size of infestations.
Landowners have a legal responsibility to control the spread of horehound weed under the South Australian Natural Resources Management Act 2004 and can contact the Natural Resources AMLR Gawler office (8523 7700) for assistance.