MidCoast Council is using its experience with the freshwater weed, frogbit (Limnobium laevigatum) to assist both Cessnock City Council (CCC) and Hunter Local Land Services.
Council has successfully controlled three infestations of the frogbit since 2017 when the invasive aquatic weed first appeared at Green Point, south of Forster.
More recently the weed was identified at the Pioneer Wetland, Forster in 2020 and in Bulahdelah in 2019.
These three sites continue to be actively monitored, but no new plants have been discovered since specialised treatment of the area.
A floating freshwater plant - which hailed from central and south America and is considered a major biosecurity threat in NSW - was more recently discovered near Cessnock when a CCC biosecurity weeds officer noticed an unusual plant on a dam during high risk pathways inspections.
Frogbit is prohibited matter in NSW, the highest class a weed can be under the NSW Biosecurity Act.
From a distance the plant appeared to be Salvinia, an established but unwanted water weed.
On approaching the dam the officer soon realised it was something they hadn't seen before.
Based on the leaf appearance and the nature of the plant the weeds officer believed the plant to be frogbit
Hunter Regional weeds co-ordinator, Matt Kennedy said the MidCoast Council weeds officer was able to identify the plant as frogbit based off the photos, so samples were then sent off for formal ID at the NSW Herbarium, which confirmed the outbreak.
"The Cessnock weeds officers didn't waste time inspecting nearby properties and utilised desktop surveillance with recent aerial imagery to highlight at risk properties," Mr Kennedy said.
It is not fully known how this and other infestations of frogbit keep popping up on private and public land across our region and in other parts of NSWHunter Regional weeds co-ordinator, Matt Kennedy
"Three more dams across two more properties were found to also have outbreaks of this high risk weed and it was deemed specialised treatment of the sites were required, as well as booms and temporary sedimentation fencing were installed to limit any possible spread."
Aerial inspections of the area were undertaken, confirming the outbreak had not spread beyond the four dams.
Spot cheeks along Black Creek have not shown any signs of frogbit establishing along its course.
From here CCC weeds officers will undertake follow up inspections and further specialised treatment as required.
Ongoing surveillance will be undertaken for at least the next three years, based on seed viability, to guarantee eradication of this highly invasive weed from our region.
"Neighbouring councils have been notified and their teams are on notice to keep a look-out for this weed downstream and on the Hunter River, with some targeted inspections underway," Mr Kennedy said.
"We're asking the community to be vigilant as well, all residents of the Hunter region are asked to play their part in safeguarding our waterways."
Identification features and detailed impacts of this weed can be found via DPI WeedWise.
The community is encouraged to send through pictures of suspected frogbit to their local biosecurity weeds officer.
Contacts details can be found at http://www.hunterregionalweeds.net.au/ or by contacting your local council.
Reports can also be made via the DPI 'Report a biosecurity concern' form online or call the Invasive Plants and Animals inquiries line on 1800 680 244.
Landholders shouldn't be concerned about reporting this weed, if they suspect it on their property.
Funding for initial treatment will be provided to cover the costs of best practice control measures.
"It is not fully known how this and other infestations of frogbit keep popping up on private and public land across our region and in other parts of NSW.
"Transplanting of the weed is known to occur and the illegal online trade of this weed species and other weed species which are a serious threat to our environment and production land are occurring through places like Facebook Marketplace cannot be ignored as one of the most likely sources of future infestations.
"When buying plants everyone should make sure they are purchasing from a reputable seller that list botanical name alongside a common name."
For information on what plants should not and must not be traded in NSW visit the NSW DPI website at https://www.dpi.nsw.gov.au/biosecurity/weeds/weed-categories
Our journalists work hard to provide local, up-to-date news to the community. This is how you can continue to access our trusted content: