June 2018 - 27th EditionNewly declared weed - the Amazon frogbitAs of January 2018, Amazon frogbit (Limnobium laevigotum) has been declared as a Class C weed (not to be introduced into the Northern Territory) under the Weeds Management Act. Amazon frogbit was recently found infesting waterways near Atherton in Queensland and is quickly smothering other freshwater systems along the east coast of Australia. It is now illegal to grow, trade, import, sell (including over the internet), or transport Amazon frogbit in the Northern Territory and any known existing plants must be destroyed. Amazon frogbit has the potential to spread quickly and devastate Top End waterways. It is a floating aquatic plant, native to Central and South America. It was imported to Australia as an ornamental aquarium plant and now poses a serious threat to aquatic environments due to its explosive rate of spread. Amazon frogbit resembles large duckweed and can be mistaken for water hyacinth.
Parks and weeds staff vs. cats claw creeper in Darwin Botanic GardensLate last year, the Weed Management Branch was contacted by staff at the Darwin Botanic Gardens who had discovered an infestation of cat’s claw creeper. Cat’s claw creeper (Dolichandra unguis-cati formally Macfadyena unguis-cati) is an aggressive vine species able to climb to the upper tree canopy and smother trees with dense, interwoven vine thickets. Cat’s claw creeper is a severe and environmentally destructive species throughout the tropics and subtropics of Queensland and New South Wales. Under the Northern Territory Weeds Management Act it is declared Class A - to be eradicated. Australia-wide, the plant is recognised as a Weed of National Significance. Alarmingly, this infestation was reasonably large and had begun smothering large trees to the point of strangulation and forming dense mats along the ground. Cat’s claw creeper had been previously observed in the Darwin region as an unremarkable semi-ornamental creeper. Its usual habit is to appear on fences and disturbed urban blocks through the wet, only to die off during the dry season. Unlike cat’s claw creeper in the eastern states, it had never been known in Darwin to climb to the canopy and suffocate large trees. The common belief was that the plant was not well suited climatically and that beyond irrigated gardens it did not prosper well through the dry season. Gardens staff contacted the Branch requesting control advice and assistance and in February the Branch, along with gardens staff and five men from the Prison Volunteer-sentence to job program, undertook physical removal, cutting and poisoning of the vines and transformed the area affected by the cat’s claw. The team was led by Glenn Holland - Botanic Gardens Arbour Technical Officer. Follow up work will be required in coming years as the vines have many small underground tubers. Additionally, there is more cat’s claw in other areas of the park to be targeted. However the work undertaken thus far is spectacular. Well done Glenn and his crew!
New weed record for Australia!Boerhavia erecta first found in the NT!A new weed to Australia, Boerhavia erecta, never recorded here before was discovered in the Darwin rural area in September 2017. This weed is on the Northern Australian Quarantine Strategy (NAQS) target weed list. It is also a declared Class C weed in the Northern Territory, for the purpose of preventing its introduction to the Territory. Boerhavia is a pretty boring looking, small, erect shrub, and can be difficult to identify. It is not considered a useful or attractive plant, so is unlikely to be accidentally grown in household gardens. A standout ID trait is purple colouring to the undersides of juvenile leaves. If you’re unsure if you have it, you can call the Weed Management Branch or send us some photos at the contact details at the bottom of the page. Plants can seed in as little as two weeks from sprouting, so the plant can rapidly establish in an area. Efforts by the Weed Management Branch and NAQS to prevent establishment of Boerharvia and investigate trace-back of its origin have pointed to the infestation originating from potting mix. The infestation was found on the property of a ‘plant collector’ who has links to other ‘plant collectors’ and nurseries in and around the Darwin area. Only two adjoining properties were found to have Boerhavia. Regular control works on the properties have reduced the number of plants from thousands to tens of plants. Weed Officers will continue to look for more plants in the area for at least a year. Gamba Action Program (GAP) update2017/18 GAP season done and dusted!Now that the gamba grass has started to produce seed heads, the Gamba Action Program (GAP) has come to an end for this season, closing on 28 April. Since the season started in November, Weed Management Officers have surveyed 1142 properties within designated ‘hotspots’ plus an additional 126 complaint blocks. We’ve attended 176 onsite inspections and placed 87 properties under order. We are proud to see that, so far, 35 of these properties were released from their orders after getting their gamba grass efficiently under control while other properties are still ongoing. The NT Government's Weed Management Branch distributed over 20 000 L of free herbicide from eight distribution points to over 2 300 GAP participants over the control season in the Darwin and Katherine regions - a new record! For more information on the GAP program, please visit: www.nt.gov.au/gamba Upcoming Events10 June 2018 TNRM Weed Management and Grass ID Workshop Contact: Susanne Casanova on 0438 765 979 or Susanne.Casanova@territorynrm.org.au 13 June 2018 TNRM Forum - Katherine 27 June 2018 TNRM Weeds Field Day - Twin Hill Station Contact: Susanne Casanova on 0438 765 979 or Susanne.Casanova@territorynrm.org.au 28 June 2018 TNRM Forum - Alice Springs 6 - 7 July 2018 Alice Springs Show 13 July 2018 Tennant Creek Show 20 July 2018 Katherine Show |