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Weed Control |
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Herbicides
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Before herbicides are used it is strongly recommended that the Water Note WN22 Herbicide Use in Wetlands (available from the Department of Environment) is consulted. |
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Arum Lily Zantedeschia aethiopica
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Arum Lily seeds remain viable in the soil for only a few months. Therefore any treatment which kills all adult plants before seed formation will eradicate an infestation.
Occasionally Arum Lily plants are found in the year after treatment. This is mainly due to late spraying after viable seed has been set, or seed from untreated areas being brought in by birds in their droppings. Some regrowth also occurs from daughter rhizomes that were not killed by the initial treatment. The only really effective treatment is Glean® or Ally® (sold in small packs as Brush-off®). This should be spot sprayed at one gram of Glean® or Ally® in a 15-litre knapsack. Both these rates are much higher than is strictly necessary but are given because of the difficulty of measuring very small amounts of chemicals. Rates for broad acre application are 20g/ha of Glean® or 15g/ha of Ally®. Wetting agent should be added to the manufacturer's recommended rate (normally 1 part to 400 of spray mix). Spraying should take place as soon as the plant starts flowering. Earlier spraying gives poorer results, while if left too late, some viable seeds will be formed. Spraying should be followed up a year later to control any plants which were missed as well as seedlings and regrowth from daughter rhizomes. Provided the first treatment was carried out properly, the second treatment should cost only a fraction of the first. As many infestations are very small and Glean® is available only in 500 gram containers, arrangements may be made to share costs with other landholders. Brush-off® is available in ten packs of five grams spelling each. Although there is no difference in efficacy or cost-effectiveness, Brush-off® is preferred by most landholders for this reason. |
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Blackberry Rubus fruticosus
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Blackberry is relatively lightly infesting the Torbay catchment. This partly reflects the low levels of remnant bush. These scattered occurrences should be a focus of action as some catchments in the region are suffering the consequences of severe infestations that become difficult to spray without killing adjacent remnant native bush.
Blackberry infestation is a problem that takes persistence to control. Mechanical control, slashing or ripping can be achieved in some situations. Suggested chemical control methods include applications of Brushoff or Trounce. 100 ml of Grazon, plus 25 ml of Pulse in 10 L of water has provided good control but damages most broad-leaved plant species. The ideal time for blackberry control is the summer months from the beginning of December to the end of March. Wetting agents (for example Pulse®) are suggested additives. Both herbicides are absorbed by the leaf so good cover of the plant is needed. Chemical reaching the ground is wasted. |
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Bridal creeper Asparagus asparagoides
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Infestations range from severe in some areas to scattered in others. Manual control is difficult but bio-control agents such as leaf hopper and a fungus can be introduced. Information on these can be obtained from the Department of Agriculture.
Very low rates of 2 g/ha metsulfuron (600g/kg) plus Pulse, or 0.02 g metsulfuron plus 25 ml Pulse®, per 10 L water can be applied with a mister or hand spray will have minimal effect on the bush. 1L glyphosate (450g/L) plus 2L of water can be used as a wipe which may be even more selective. |
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Bulrush (Cumbungi) Typha orientalis
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Bulrushes can choke swamps and dams. Non-chemical methods of control can be effective early in an infestation where there is standing water. The stems can be cut below water level or as winter water level is rising. This drowns many plants, but takes persistence for success.
Herbicides glyphosate (100ml, 450g/L plus 25 ml Pulse®, in 10L water) and 2,2 DPA also provide good control if 60% of the flower is above water at flowering when herbicides are applied. The spray does work at other times. |
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Pittosporum Pittosporum undulatum |
Pittsporum can become a severe weed in creeklines and can establish within remnant bush successfully. This species is creeping out from Torbay Townsite area and also is established along and adjacent to the South Coast Highway. Manual control can be effective if seedlings are controlled in subsequent years. | |
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Sydney Golden Wattle Acacia longifolia |
Sydney Golden Wattle is a limited problem in the catchment with a few outbreaks, but as evidenced in other areas of the City of Albany local government area infestation can quickly become severe. It is a weed that should be monitored and its spread halted in the early phase of infestation.
Eradication by mechanical methods / by hand is possible for small infestations and is recommended. Chainsaw at ground level and be aware of seedling germination in subsequent years. |
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Taylorina Psoralea pinnata
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Removal by hand clearing or selective spraying is effective. Spray with the herbicide "Metsulfuron methyl" (Ally, Brushoff) at a rate of 10g per 100lt of water. Add a wetting agent such as "Pulse" at 1 part per 400 mixture. Wet the entire canopy and trunk with this mixture. Mature trees can be lopped well below the lower branches and painted with "Access" mixed in distillate at a ration of 1 part per 60 distillate. Coppicing will not occur.
Seedlings can be removed by hand. Monitor annually for seedlings. Protect cleanest areas as a priority, and plan the order and priority for tackling larger infestations. Replanting with native plants is important if insufficient occur on site. |
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Watsonia Watsonia sp.
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Grazing provides effective control in areas with no native bush. Chemical treatment by spraying with Roundup Bi-active 360g/l (1 part per 100 of water) or with 2,2- DPA (Dalapon) at 10kg per ha (1kg per 100L of water), plus a wetting agent, spot spray as flower spikes emerge. Dalapon is considered less environmentally damaging than Roundup. Although this formula is designed to be used in wetlands, great care should be exercised to prevent spray drift, which may damage nearby native plants. Isolated plants may be removed by hand. Flower stalks bearing aerial corms or seeds should be cut and bagged and removed from the site. Protect cleanest areas as a priority, and plan the order and priority for tackling larger infestations. Replanting with native plants is important if insufficient natives occur on site.
The Torbay Catchment Group have specifically targetted Watsonia in an on-going weed eradication program in the catchment. |
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| Weeds to be vigilant for in the future |
Blue Gums (Eucalyptus globulus)
Blue gums have been planted as wind breaks and as riverine plantings in the catchment. These trees are capable of producing viable seed at around 15 years of age that can infest remnant native bush.
Victorian Tea Tree (Leptospermum laevigatum) Victorian Tea Tree is a major weed in Albany and is present but is in low numbers in most of the Torbay catchment. Acacia species Many species have been planted as windbreaks and amenity plantings in the Torbay townsite area. These species need vigilance as many varieties which are not of local provenance are becoming significant weeds of remnant bush and riverine areas. Tasmanian Blackwood (Acacia melanoxylon) Planted for its excellent timber, this species can seed prolifically and sucker from roots. Vinca Major (Apocynaceae) A few outbreaks of this creeper/groundcover exist in the catchment. Locally it can be a problem weed that can choke road verges or small patches of bush. It does not usually develop into a widespread weed. Cape Tulip (Moraea miniata) There is an outbreak adjacent to the Torbay main drain and Meanwood Road. It is toxic to stock. Control can be achieved by hand spraying until just wet in June to early September each year with one of the following mixtures: 0.2 g of chlorsulfuron (750g/kg) or metsulfuron (600g/kg) or 100ml glyphosate (450g/L) in 10 L water plus 25mL Pulse®. |
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