Give them back, before they get out!
Invasive aquatic weed found for sale
in the Territory Sagittaria (Sagittaria platyphylla) is a highly invasive aquatic plant that lives in or around fresh water.
The Weed Management Branch seized and destroyed dozens of sagittaria, labelled as ‘melon sword’ following their recent discovery at Darwin and Palmerston Bunnings stores and Mitre 10 in Katherine.
Unfortunately a number of plants were sold before detection. A public recall was the best option to try and get back these plants and make the public aware of the massive risk these plants pose to the Territory.
During the recall, the Branch was contacted by a Howard Springs resident who reported sagittaria growing in a pond on their property. These plants were positively identified as sagittaria on 8 November 2016. As these plants are reported to have been in situ for approximately 10 years, they raise concerns that sagittaria may have spread and become naturalised in surrounding areas. Given the level of risk posed, the Branch is immediately conducting surveys of suitable habitat including lagoons, drainage lines, floodplain, dams and ponds.
The recall is still ongoing. If you think you may have purchased this plant please call the Weed Management Branch immediately. Learn more >
Cacti Collection Month - Alice Springs
Cutting cacti out of your life is now a necessity if your garden contains varieties that have been recently declared as Class A weeds. Declared cacti include prickly pears, and rope cactus as well as many varieties of Opuntia and Cylindropuntia (collectively referred to as opuntioids).
All declared Class A cactus infestations and plants (including garden plants) must be eradicated according to the Weeds Management Act. These cacti have been declared across Australia because of their impacts which include environmental damage and injury, pain and suffering to stock and native animals through spine impalement and lodgement of spiny segments in skin and mouth.
Opuntioid cacti are still in the early stage of invasion in the Northern Territory. Most infestations are still relatively small meaning that there is a high chance of achieving eradication by applying herbicide or physically removing plants.
In Central Australia, the Department of Environment and Natural Resources, in partnership with the Alice Springs Town Council, Cleanaway and Alice Springs Landcare Group have developed a system using wheelie bins, to get cacti safely from gardens to the dump while minimising the risk of spread or injury. Alice Springs residents are encouraged to ‘Bin It, Don’t Spread It’ by getting cacti out of their gardens before summer sets in. Landholders can now dig out their declared cactus and dispose of all plant material into wheelie bins for kerbside removal to the waste management facility.
Waste containing cacti will be buried at the dump to prevent cacti re-sprouting and spreading further. Please don’t transport cacti yourself and never dispose of them in green waste. Weed Management Officers will be providing affected landholders with early detection and control advice. Officers can also to help identify newly declared species in urban gardens.
For further advice on cactus ID and how to control cactus contact the Weed Management Branch by phone 8951 9210 or email weedinfo@nt.gov.au or visit www.nt.gov.au/weeds
It’s that time of year again…gamba grass control season! Early rains have provided perfect early growing conditions for gamba. Get in and spray your gamba grass before it gets too wet or too big!
The 2016/17 wet season will again provide you with the opportunity to get free herbicide and equipment loans to control gamba grass on your properties through the Gamba Action Program.
You may have noticed a slight name change of the program this season as we move from an assistance program into an action focus – action for control, action for accountability and action for compliance. Learn more >
New Gamba Action Vehicle ‘GAV’ and new staff Dedicated gamba grass compliance staff will be out and about in ‘GAV’ over the coming months ensuring the public are being compliant in their requirements to manage gamba grass on their properties. Over 2000 land holders participated in last year’s gamba grass assistance program. This year we are hoping to ‘drive’ numbers to the 3000 mark.
Gamba grass density in the Darwin region.
Where do you sit in the landscape? How do we collect this data?
Data is collected mostly via aerial surveys in a helicopter utilising two observers with specialised laptops and customised software.
The software beeps every 200m travelled (about every 6 seconds) and observers record gamba density, (percentage of ground covered by gamba) approximately 250m each side of the helicopter along flightpaths around 500m apart. The helicopter flies at 60 knots (approx. 100km/h) at 300 feet altitude.
Gamba density is recorded on a scale of 1 to 5, with 1 being none and 5 being over 50% ground cover (shown as red on the map).
This data is then loaded into a geographic information system (GIS) to produce gamba grass density and distribution maps (see map adjacent).
What is the data used for?
With a bit of planning, maps like this help affected land managers to determine the most appropriate management actions and, importantly coordinate their efforts and ensure time and money invested contributes to long term weed management.
Maps can help to prioritise management actions, by identifying clean areas or assets requiring protection from weed invasion. Knowing where weeds are, or aren't, and preventing their spread is always the most successful and cheapest way of managing weeds.
Cabomba is an aquatic weed that can choke waterways and impacts fisheries. The Weed Management Branch is intensively controlling the only known infestation of cabomba in the Territory with the aim of eradicating it once and for all. SharkTM herbicide is currently being applied in affected areas of Darwin River. Preliminary results are positive showing a marked decline in cabomba health and extent, but the program will be on-going in 2016/17.
A bund wall was constructed at the Cox Peninsula Road bridge to prevent the potential flow of the herbicide into Darwin Harbour. The water held back by the bund wall was subject to a NT EPA Waste Discharge Licence to ensure that strict water quality standards were met. Water quality monitoring results have shown that herbicide was not detected within the 1.5 km of river upstream from the bund wall, indicating the chemical’s breakdown rate was more rapid than expected. As a result bund wall deconstruction is now underway to avoid the risk of blow out and sedimentation associated with early monsoon.
The Eradication Team has also developed a range of community awareness material to help spread the word on the serious risk cabomba places on the Top End waterways, including posters, drink coasters, fact sheets, information online, a television commercial and social media videos.
Watch the Cabomba eradication program video
Remember if you see it, report it!. Learn more >
The Darwin River Quarantine zone remains in place to prevent cabomba spread and to keep members of the public away from herbicide treatment areas. People found within the Quarantine Zone can be fined on the spot or may potentially face court. The Weeds Management Act stipulates a minimum $11 000 penalty if found guilty for breaching an established Quarantine zone.
New weeds declared in the Territory Weeds of National Significance (WoNS) are Australia’s worst weeds. In 2011, 12 new weeds were added to this list. Four of these were already declared in the NT. These were African boxthorn, bellyache bush, gamba grass and water hyacinth. National consistency requirements meant the remaining species were declared in the Northern Territory in July 2016.
Cat’s claw creeper and opuntoid cacti (prickly pears and their relatives) were declared Class A (to be eradicated) and Class C (not to be introduced in the NT) throughout the Territory. All known plantings are now being targeted for eradication. Asparagus weeds (five species); brooms (three species); fireweed; madeira vine; silverleaf nightshade and sagittaria had not been known to have occured and in the Territory. They were classified as Class C to prohibit their entry or sale. So basically, what all of this means is…you are not allowed to sell, buy, transport or have any of the weeds mentioned above.
The declaration preceded the recent sagittaria findings described earlier. Sagittaria has now been declared Class A (to be eradicated).
Gamba grass and bellyache bush are both high priority weeds that must be managed in accordance with their respective statutory weed management plans. Declared list>
New management requirements for Grader Grass In July the statutory Weed Management Plan for Grader Grass (Themeda quadrivalvis) was legislated.
Grader grass is an invasive introduced grass that can
out-compete native vegetation, leading to reductions in pastoral productivity and reduced biodiversity.
The new Plan sets out the management actions required by all persons, to manage grader grass and to mitigate its impacts.
The Plan initiates a proactive approach to control, monitoring and spread prevention.
Grader grass is widespread throughout the Katherine region and presents significant management challenges on a range of land tenures. Preventing the spread of this weed into areas that are currently free of grader grass is a high priority.
Grader grass seed can be spread by machinery contaminated with seeds, including slashers and graders. It can also be spread by contaminated fill, gravel and hay. Learn more >
Weed Management Branch
Darwin 8999 4567
Katherine: 8973 8857
Tennant Creek: 8962 4314
Alice Springs: 8951 9210
email: weedinfo@nt.gov.au
www.nt.gov.au/weeds
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