Control methods - Office of Environment and Heritage

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Control methods

Plan before you control Key control considerations Control method decision matrix

32 33 34

Manual methods Chemical methods Other control methods

34 37 51

Comparison of control methods

58

Hillary Cherry

Terry Inkson, Great Lakes Council

Alan Kwok

Detailed overview of control methods

32

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SECTION 4:

Control methods C

Plan before you control It is critical that you plan your control program thoroughly before undertaking any control activities. Have you conducted appropriate planning and prepared a site management plan? Information to help you prepare a management plan for bitou bush is provided in Sections 2 and 3.

Key control considerations 1. Choose appropriate methods Choose appropriate control methods for your site according to the terrain, habitat, sensitivity of your site, the size and density of the bitou bush infestation and the objectives of your management plan. For example, if you are managing for biodiversity, use the control method and time of application which coincides with the least vulnerable growth stage of the native species you are trying to protect. Which method should I use? There are many methods available to control bitou bush. They vary in cost, not all are applicable in every situation, and all have advantages and disadvantages. The choice of method will be dependent upon your resources, the specifics of your site and the objectives of your management plan (see Section 2). Thus selecting an appropriate control method for each situation may be challenging.

An integrated approach does not need to be complicated. It may be as simple as using different methods for initial and follow-up control – for example, mature plants might be treated with a herbicide application, whilst the seedlings that subsequently germinate might be handweeded.

3. Follow-up what you started One of the greatest contributors to the success of any bitou bush control program is commitment to an appropriate follow-up control program. Often the initial control is undertaken over too large an area for followup control to occur, or follow-up control is not maintained for sufficient time to achieve a successful outcome. Post-control germination of bitou bush can be high initially, however sustained control of these seedlings, over several years before they mature and set seed, can greatly reduce numbers and the size of the seed bank. Exhausting the seed bank may take a decade or more, hence followup activities will be needed over this period. Also consider potential ongoing re-infestation particularly through birds bringing in seeds from neighbouring untreated infestations.

To help you decide on an appropriate method, a decision matrix has been created (see page 33) which assesses the appropriateness of each control method within each habitat type invaded by bitou bush (see Section 3 for habitat descriptions and environmental considerations).

Often the most successful and cost-effective approach to controlling weeds is to combine or integrate several control methods over time – known as integrated weed management.

32

Stephen Booth

2. Integrate methods

Control method decision matrix To choose an appropriate method, identify the methods suitable for your habitat type (below). Then, read about how to apply each method (following pages) and compare their advantages for your situation (page 58) before you finalise your decision. Control method

Management issue #

Habitat type #

Stem injection Hand Cut-and- / scrape- Foliar Splatter weeding Crowning paint and-paint spraying gun

Aerial boom spraying

Aerial spot Mechanical spraying methods

Fire

Biological control

Page

34

35

42

43 / 44

45

47

48

50

51

52

55

Foredunes 22

9

9

9

9

9

9

9

9

9

9

9

9

9

9

9

9

 

9

Dune crests 22

 

Hind dunes 23

9

9

9

9

9

9

}

9

}

}

9

Coastal heath and 23 scrub

9

9

9

9

9

9

}

9

}

}

9

Littoral rainforest 24

9

9

9

9

9

9

* *





9

Woodlands 24

9

9

9

9

9

9

}

}

}

}

9

Headlands 24

9

9

9

9

9

9

9

9

}

}

9

Steep slopes 24

}

}

}

}

9

9

9

9





9

Riparian areas (incl. 24 tidal rivers & estuaries)

9

9

9

9

}

9



}





9

Outlier, small or 27 isolated infestations

9

9

9

9

9

9



9





9

Heavy infestations 27

9

9

9

9

9

9

9

9

}

}

9

Unstable soils 27

}

}

9

9

9

9

9

9





9

Native species at threat 28 from bitou bush

9

9

9

9

}

}

}

}



}

9

Depleted native 28 seed bank

9

9

9

9

9

9

9

9

9

}

9

Culturally sensitive 28 areas

}

}

}

}

}

}

}

}



}

9

9

# Described in Section 3.

9

Suitable control method.

 Control method NOT RECOMMENDED. } Further considerations are required – see specific description of the method along with the advantages/ disadvantages of the method before using it.

* Aerial boom or spot spraying of littoral rainforest is NOT LEGALLY PERMITTED in New South Wales because it is an Endangered Ecological Community (see Section 8 for information on the NSW Threatened Species Conservation Act 1995).

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SECTION 4:

Control methods C

Detailed overview of control methods Manual methods Handweeding page 34 Crowning page 35

Manual methods Manual control methods use no tools or only hand tools – methods include handweeding and crowning.

Handweeding Bitou bush has a relatively shallow root system with no taproot, therefore seedlings and young plants can be pulled out by hand without the need for tools – this is called handweeding (or handpulling).

Chemical methods Cut-and-paint page 42 Stem injection / scrape-andpaint pages 43 / 44

Splatter gun page 47

Hillary Cherry

Foliar spraying page 45 Grasp the stem close to the ground

Applying the method Aerial boom spraying page 48 Aerial spot spraying page 50

Other control methods Mechanical methods page 51 Fire page 52 Biological control page 55

34

For small seedlings, take hold of the stem at ground level and pull out vertically. The young stem bends abruptly at almost 90 degrees after it enters the soil and the plant tends to break at this point unless extracted slowly. Young plants should ideally be removed before they first flower and set seed. Larger plants should be rocked backwards and forwards gently until they come away cleanly, or use a leverage tool (e.g. the ‘Peter Lever’). In areas of heavier soils you may need to wait until the soil is moist (i.e. after rain). Adult plants should ideally be removed when they are not in fruit to limit the spread of seeds. It is important to replace any disturbed soil as you go to reduce erosion and encourage regeneration of native seedlings. Plants must be left to decay on site; it is illegal to transport bitou bush in all Australian states

and territories (see Section 8). Branches can be cut to form a mulch layer which may be beneficial in sandy or exposed areas (see page 67). Ensure the roots are not left in contact with the soil to prevent re-establishment. Dead plants can help you to locate areas for followup. Follow-up will be required to control recruitment of bitou bush seedlings. Timing Any time of the year. Suitability of the method Plant age – seedlings and young plants. Habitat type – any, except where bitou bush roots are stabilising soils (e.g. cliffs or steep dune faces); ideal for natural areas. Size of infestation – isolated infestations, scattered plants or infestations that cover a small area. Advantages

Applying the method Remove all small bitou bush seedlings or other weeds and topsoil from around the base of bitou bush plants you want to treat to expose the roots. Check for native roots entangled in bitou bush roots and if present, work carefully. Cut off higher branches to expose the stem and base, if necessary. Using loppers or a pruning saw, sever all bitou bush roots around the crown – near the base of the primary stem of the plant. Check for and cut off all heels (small pieces of stem still connected to the top of the root) on roots. Leave plants to decay on site. Branches can be cut into lengths to form a mulch layer (see page 67). If leaving branches and foliage in the canopy, prop the cut base off the ground to prevent re-rooting. Replace topsoil and cover disturbed area with surrounding leaf litter, if necessary. Follow-up will be required to control recruitment of bitou bush seedlings.

Marion Winkler

• Causes no or minimal damage to desirable vegetation. • Selective (i.e. only bitou bush is removed). • Whole plants are removed preventing regrowth. • Provides easy access for follow-up works. • No chemicals or equipment required. • Low cost. • Applicable for use with threatened species. Disadvantages • Labour intensive and time consuming. • Limitations if working with very large plants. • Not applicable in some situations.

Crowning

Ellen White

The manual control method known as ‘crowning’ works by cutting the stem away from the roots below the ground level, or cutting out the ‘crown’ of the plants. This is effective as the fibrous network of roots do not regrow if the primary stem (or crown) is entirely cut out. Sever roots close to the crown using loppers or a bush saw

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Timing Any time of the year. Suitability of the method Plant age – all plants; ideal alternative to handweeding large plants. Habitat type – any; ideal for natural areas. Size of infestation – isolated infestations, scattered plants or infestations that cover a small area. Advantages • Causes minimal soil disturbance. • Selective (i.e. only bitou bush is removed).

• Causes no or minimal damage to desirable vegetation. • Provides easy access for follow-up works. • A gradual defoliation of the plant in situ may have benefits for the protection of native species. • No chemicals required. • Low cost. Disadvantages • Labour intensive and time consuming. • Not applicable in some situations (e.g. on steep slopes).

‘Crowning’ successful on bitou bush at Dirawong Headland The Dirawong Reserve, just north of Bundjalung National Park in New South Wales, is an example of large scale removal of bitou bush and other associated weeds using the ‘crowning’ method and handweeding.

“In the large areas completely dominated by bitou bush, the ground is often apparently bare immediately after removal, so erosion is prevented by coverage with the uprooted bitou bush.” Local volunteers, EnviTE (Environmental Training and Employment Inc.), and people on Community Service Orders have worked on the reserve consistently since 2003. This contributed to the longer running bush regeneration program to remove bitou bush, particularly after the wildfire in 2000, so by early 2007, three kilometres of coastline were virtually bitou At the beginning of work (above) and after control (below) bush free (about 40 hectares).

36

Ellen White

Ellen explains, “On the Dirawong, we have found that the manual techniques of handweeding and crowning bitou bush plants is less time consuming and expensive than the use of a cut-and-paint method. From a risk management perspective, it does far less environmental damage than ground or aerial spraying. It also has the advantage of instant accessibility for follow-up compared to spraying and it can be used in all weathers.

Ellen White

Ellen White of the Dirawong Trust explains, “Because of the environmental sensitivity and cultural significance of the Dirawong, we use the ‘crowning’ method instead of using herbicides on bitou bush plants which are not easily pulled and may be up to 4–5 m tall. We use spot spraying by contractors only on steep, inaccessible slopes.”

Chemical methods When used as part of an integrated management strategy, chemicals (herbicides) can be a practical and efficient way of controlling bitou bush. Six herbicide application methods are currently registered and/or permitted for use on bitou bush: • Cut-and-paint, • Stem injection, • Scrape-and-paint, • Foliar spraying, • Aerial boom spraying, and • Aerial spot spraying.

are restricted in certain states or in specific areas of the state. Herbicides must be stored in properly labelled containers, preferably in the original container and in a locked cabinet. Only chemicals that are registered for use in aquatic situations may be used in and around aquatic areas. By law, you must read the label (or have it read to you) before using any herbicide product. Always follow the label instructions. The same applies for off-label permits.

Important information below is to assist you to use herbicides in a safe manner and in accordance with the relevant legislation. Herbicide labels and legislation The Australian Pesticides and Veterinary Medicines Authority (APVMA) controls and regulates the use of all pesticides (this includes herbicides). The APVMA approves the use of herbicides to control a weed and sets the label recommendations. By law, only herbicides registered for bitou bush control (by the APVMA) can be used on bitou bush, and only in the manner specified on the label. Keep a written record of all herbicide use.

The APVMA also issues permits for herbicide applications that are not otherwise registered, these are often referred to as ‘off-label’ permits. A variety of off-label permits for bitou bush control are held by government departments and individuals and can be used by other individuals or groups with permission from the permit holder. See the APVMA website for more information. Be aware of legislation in your state regarding herbicide use – for example, some chemicals

Marion Winkler

Because new chemical products are registered on a regular basis and existing chemicals are reviewed routinely, you should check the APVMA website regularly to ensure you are not breaching any laws (www.apvma.gov.au). A search engine for registered herbicides is also available at www.pestgenie.com.au. All herbicide use should be recorded in a record book

Safety and training Personal protective equipment (such as protective clothing, eye or face shields, and respiratory protection) must be used in accordance with the recommendations stated on the herbicide label or permit. Chemical use training is required for people using herbicides as part of their job or business. Training is

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recommended for community groups and may be required if working on public land. Training courses are run by ChemCert and TAFE in each state. Other training courses may be available through state agencies (e.g. AgTrain in Victoria, SMARTtrain in New South Wales, and AgForce in Queensland), local councils or non-government organisations (see Section 8).

their use are also shown. Check the APVMA website for current registration and permit information (www.apvma.gov.au), and always check the label for the correct application rate. It may be beneficial to choose herbicides that can treat multiple weed species at one time. For information on which herbicide is most appropriate in your patch, contact your local weeds officer. The active ingredients in herbicides registered for use on bitou bush are glyphosate, metsulfuron methyl, picloram, 2,4-D amine and bromoxynil; some of these are used in combination. The characteristics of the most commonly used herbicides are described below. This information does not imply any recommendation of a specific herbicide, and individual site requirements must be considered when choosing a herbicide. The information below comes from The Pesticide Manual by C. Tomlin, published in 2003 by the British Crop Protection Council and relevant herbicide labels (for these herbicide labels see the APVMA website).

Mick Richards

Glyphosate

Wear personal protective equipment when using herbicides

Registered herbicides There are many different herbicide products registered for use on bitou bush. It is important to check that each herbicide product is registered in your state or territory for the particular application method you are planning to use. The table on page 40 lists the herbicides registered for use on bitou bush and the states in which these registrations apply. Herbicides that are not registered for use on bitou bush but which have off-label permits covering

38

Glyphosate is a non-selective herbicide (it targets both grasses and broad-leafed plants) that is absorbed through leaves and green stems and then moves rapidly (translocates) to actively growing parts of the plant. It is usually applied diluted in solution to the leaves, or neat (100% strength) to cut stems. The herbicide then interferes with the formation of amino acids which are essential for the growth of plant cells. The particular amino acids disrupted are present in plants, fungi and bacteria, but not in animals. Glyphosate is rapidly deactivated on contact with the soil because it binds to soil particles. It is broken down in the soil by microbial activity. The average half-life of glyphosate in soil is 32 days (half-life is the time taken for the concentration of herbicide to be halved). The rate of decomposition depends on temperature, soil moisture and the organic matter content of the soil.

Success using glyphosate Numerous Bushcare and Coastcare programs have consistent success using glyphosate in their control efforts. Volunteers who are trained in the safe use of chemicals find “glyphosate is effective, has few restrictions on its use, is cost-effective and requires less safety training than other chemicals, making it ideal for use by community groups”. – Peter Tucker, Technical Officer with Bush for Life.

Metsulfuron methyl Metsulfuron methyl is a selective herbicide (it targets only broad-leafed plants) that is absorbed through both roots and leaves. It is usually applied in solution to the leaves, then moves rapidly through the plant (translocates) and inhibits the enzyme required for the production of amino acids necessary for cell division. The particular enzyme affected is not present in animals. The residual activity of metsulfuron methyl varies with soil type, soil pH and organic matter. The soil activity of metsulfuron methyl may be reduced by the presence of high carbon levels following fires. Metsulfuron methyl is broken down by microbial activity and chemical hydrolysis. The average half-life of metsulfuron methyl in soil ranges from five days in acidic soils to 69 days in alkaline soils. Also, leaching of metsulfuron methyl is greater in alkaline soils and sands. Success using metsulfuron methyl Bush regenerator Stephen Booth has had particular success using metsulfuron methyl in littoral rainforest areas. Stephen accepts the trade-off that “metsulfuron methyl can be residual for a short time in the soil, which could inhibit native seed germination in the short-term, but it is not likely due to the free draining sandy soils in the area”. He says, “we use metsulfuron methyl because we can use the same rate of application (1 g/10 L) all year round, plus metsulfuron methyl is effective in treating a suite of other weeds on the site, particularly where glory lily, mistflower, crofton weed, etc. are present”.

Picloram Picloram is a selective herbicide (it targets only broad-leafed plants) which is absorbed through roots and cut stems and moves (translocates) throughout the plant. For bitou bush it is usually applied in a thick gel directly to cut stumps. It is slow-acting and can take 2–3 months for the symptoms to appear and up to six months or two growing seasons after application to completely kill the plant. The herbicide can remain active within the plant for up to two years. It affects the synthesis of proteins, disrupting cell growth. Picloram is a very persistent herbicide. It may remain active in the soil for more than a year depending on the rate of application, soil characteristics and climatic conditions. It does not bind strongly with soil and can suppress seed germination and plant growth for some time after treatment. Picloram is degraded in soil and water mainly by microbial activity. Success using picloram Terry Inkson, the Noxious Weeds Inspector at Great Lakes City Council says the council chooses to use picloram in a gel application especially for volunteer use because “it is easy to apply and is a highly effective product. The thick gel form that we use also minimises spillage.” Safety is an important concern when working with volunteers. “The picloram product we use improves our OH & S” because of the gel formulation. “We also find the use of picloram beneficial because we can purchase small (240 g) containers, that each come with individual applicator caps and herbicide labels. The small size of the container also means volunteers can use it without the need for ChemCert training, although we do provide in-house training and inductions for our volunteers on the correct techniques for use of chemicals.”

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Summary of registered herbicides for bitou bush control (as at September 2008) Situation (as per label/permit)

Comments (PERXXXX denotes permit number)

Undiluted (gel form)

Native vegetation, conservation areas, gullies, reserves and parks

Apply 3–5 mm layer of herbicide gel to cut stump from ‘brushbottle’ supplied

QLD, NSW, VIC, SA, WA

1 L/10 L water

Pastures, rights of way, commercial and industrial areas

Apply as spray to freshly cut stump at any time of year

Roundup®, Roundup® Biactive™, Weedmaster® Duo, Nuturf Razor, Biochoice™ 360

NSW

1:1.5 with water

Urban bushland and forests, and coastal reserves



Roundup®, Roundup® Biactive™, Weedmaster® Duo, Nuturf Razor, Biochoice™ 360

QLD

Undiluted to 1 L/12 L water

Non-agricultural areas, bushland, forests, wetlands, coastal and adjacent areas

PER7485, expires 30/6/2009 • Applicable method valid if bitou bush is woody • Paint stump immediately after cutting

metsulfuron methyl 600 g/kg

Brush-off ®

NSW

1–2 g/10 L water

Urban bushland and forests, and coastal reserves

PER9158, expires 31/3/2010 • In coastal reserves, only products registered for use in aquatic areas should be used • Best applied in winter months

glyphosate 360 g/L + metsulfuron methyl 600 g /kg

Roundup® + Brushoff ®

NSW

Tank mixes of 1:1.5 glyphosate + 1 g metsulfuron methyl per 1 L water

Areas of native vegetation e.g. subtropical rainforest remnants, littoral rainforest and other bushland reserves

PER9907, expires 31/3/2012 Application method valid if bitou bush is woody

glyphosate 360 g/L C

Roundup®, Roundup® Biactive™, Weedmaster® Duo

NSW

Undiluted herbicide to 1:1.5 in water

Areas of native vegetation e.g. subtropical rainforest remnants, littoral rainforest and other bushland reserves

PER9907, expires 31/3/2012 Application method valid if bitou bush is woody

Roundup®, Roundup® Biactive™, Weedmaster® Duo

QLD

Undiluted to 1 L/2 L water at 1 mL per 2 cm of hole or cut

Non-agricultural areas, bushland, forests, wetlands, coastal and adjacent areas

PER7485, expires 30/6/2009 • Applicable method valid if bitou bush is woody • Paint stump immediately after cutting

glyphosate 360 g/L C

Roundup®, Roundup® Biactive™, Weedmaster® Duo

NSW

Undiluted herbicide to 1:1.5 water

Areas of native vegetation e.g. subtropical rainforest remnants, littoral rainforest and other bushland reserves

PER9907, expires 31/3/2012 Application method valid if bitou bush is woody

glyphosate 360 g/L C

Roundup®, Roundup® Biactive™

QLD, NSW, VIC, TAS

5 or 10 mL/1 L water

All situations

Best results achieved when treated at peak flowering during winter. Use higher rate on plants over 1.5 m high D

Roundup®, Roundup® Biactive™, Nuturf Razor, Biochoice™ 360

NSW

1 mL/100–200 mL water

Urban bushland and forests, and coastal reserves

PER9158, expires 31/3/2010 • In coastal reserves, only products registered for use in aquatic areas should be used • Best applied in winter months

Roundup PowerMAX™

All

50–100 mL/15 L water

Around buildings, commercial and industrial areas, domestic and public service areas, right of ways, dry drains and channels only, forests and farm situations



Active ingredient

Commercial product examplesA

picloram 43 g/kg

Vigilant®

All

picloram 75 g/L + 2,4-D 300 g/L

Tordon™ 75-D

glyphosate 360 g/L C

Foliar spraying page 45

Scrapeand- paint page 44

Stem injection page 43

Cut-and-paint page 42

Application method

40

glyphosate 540 g/L C

State or territoryB

Rate

PER9158, expires 31/3/2010 In coastal reserves, only products registered for use in aquatic areas should be used • Best applied in winter months

• •

Best results achieved when treated at peak flowering during winter Use higher rate on plants over 1.5 m high D Do not apply to weeds growing in or over water

glyphosate 680 g/L C

Roundup® Dry

QLD, NSW, VIC, TAS

5 g/L water

Around buildings, commercial and industrial areas, domestic and public service areas, right of ways, dry drains and channels only, forests and farm situations

Apply when plants are actively growing. Do not apply to weeds growing in or over water

metsulfuron methyl 600 g/kg

Brushmaster

All

10 g/100 L water

Native pastures, rights of way, commercial and industrial areas

Spray thoroughly to wet all foliage

Bushwacker® WG Brushkiller™ 600, Brush-Off ®

QLD, NSW, VIC, SA,

10 g/100 L water

Pastures, right of way, commercial and industrial areas

Spray thoroughly to wet all foliage

Situation (as per label/permit)

Comments (PERXXXX denotes permit number)

95 g/100 L water

Pastures, rights of way, commercial and industrial areas

Spray thoroughly to wet all foliage

QLD, NSW, VIC, SA, WA

650 mL/100 L water

Pastures, rights of way, commercial and industrial areas

Spot spray when flowering or fruiting

Bronco 200, Bromo 200, Bromicide® 200

VIC, TAS

160 mL/100 L water + Spraymate Activator (125 mL/100 L spray)

Pastures, roadsides and rights of way

Spot spray for young seedlings

Roundup®, Roundup® Biactive™, Wipe-Out 360

QLD, NSW, VIC, TAS

1:29 or 1:19 with water

All situations

Use higher rate (1:19) on bushes over 1.5 m high4

Weedmaster® Duo

All

1:29 or 1:19 with water

For general weed control in domestic areas, commercial, industrial and public service areas, agricultural buildings and other farm situations

Spray thoroughly to wet all foliage. Use higher rate (1:19) on bushes over 1.5 m high4

metsulfuron methyl 600 g/kg

Bushwacker® WG

QLD, NSW, VIC, SA

1 g/L water + Spraymate Freeway (10 mL/5 L spray)

Pastures, right of way, commercial and industrial areas

Spray thoroughly to wet all foliage

glyphosate 360 g/L E

Roundup®

NSW

2 L/ha

Coastal sand dunes and coastal bushland

Permit available to qualified people who hold a current pilot licence in New South Wales to apply herbicide by air. For wetlands and other aquatic areas ONLY use glyphosate based herbicides approved for use in aquatic areas

1.8–3.0 L/ha

Coastal sand dunes

Permit available to qualified people who hold a current licence in New South Wales to apply pesticide by air and who comply with the requirements of Pesticide Order AIR-1

Active ingredient

Commercial product examples1

State or territory2

glyphosate 760.5 g/kg + metsulfuron methyl 63.2 g/kg

Cut-Out®

QLD, NSW, VIC, SA, ACT

picloram 75 g/L + 2,4-D amine 300 g/L

Tordon™ 75-D

bromoxynil 200 g/L glyphosate 360 g/L C

Aerial spot spraying page 50

Aerial boom spraying page 48

Splatter gun page 47

Foliar spraying (continued) page 45

Application method

Rate

metsulfuron methyl 600 g/kg

Brush-Off ®

NSW

20–30 g/ha

Coastal sand dunes

Permit available to qualified people who hold a current licence in New South Wales to apply pesticide by air and who comply with the requirements of Pesticide Order AIR-1

glyphosate 360 g/L E

Roundup®

NSW

0.5–1.0 L/100 L water

Coastal sand dunes and coastal bushland

Permit available to qualified people who hold a current pilot licence in New South Wales to apply herbicide by air. For wetlands and other aquatic areas ONLY use glyphosate based herbicides approved for use in aquatic areas

1:100 with water

Natural ecosystems

Permit available to staff or contractors employed/contracted by the NSW DECC or agencies/organisations represented on regional weeds advisory boards

10 g/100 L water

Coastal sand dunes, bushland and grassland

Permit available to staff or contractors of NSW DECC or agencies/organisations represented on the Far North Coast or Mid-North Coast regional weeds advisory boards

1–2 g/10 L water

Natural ecosystems

Permit available to staff or contractors employed/contracted by the NSW DECC or agencies/organisations represented on regional weeds advisory boards

metsulfuron methyl 600 g/kg

Brush-Off ®

NSW

A

Commercial products listed here are examples only, and many other products containing these active ingredients are registered for use on bitou bush, visit www.apvma.gov.au. Products may be registered for use on bitou bush in all states and territories (shown as ‘All’) or only in the specific states and territories listed. C Products containing different concentrations of the active ingredients 2,4-D amine and/or glyphosate are also registered for use on bitou bush in various states, visit www.apvma.gov.au or www.pestgenie.com.au. D Some manufacturers specify using a higher rate on plants over 1.5 m high. E Other registered products containing 360 g/L glyphosate are included in this permit but have not been trialled in aerial spray trials for their impact on native plants. B

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Cut-and-paint Also called cut-stump or cut-and-swab, the cut-and-paint method involves cutting the plant off at the base of the stem and immediately applying herbicide to the stump. Always read and follow all directions on the herbicide label and relevant permit, including usage restrictions (e.g. use is often restricted in wet weather).

before the plant cells close up and inhibit entry of the herbicide. Herbicide can be applied using a paint brush, a squeeze bottle, a sponge-tipped bottle or a spray bottle – some herbicide products even come with a special spongetipped attachment, see table on page 40. On large stems, apply the herbicide to the outer sapwood (cambium layer) only. Sapwood will transport the herbicide to the roots. Leave plants on site to decay. Branches can be cut into lengths to form a mulch layer (see page 67). Follow-up will be required to target recruitment of bitou bush seedlings. Timing Any time of the year (weather permitting). Most effective when bitou bush is actively growing so that herbicide is rapidly transported to the roots.

Kerry Brougham

Suitability of the method Plant age – all plants; useful for plants that are too large to handweed or be crowned. Habitat type – any; ideal for use in native ecosystems as there is limited chance of offtarget damage or soil disturbance. Size of infestation – isolated infestations, scattered plants or infestations that cover a small area. Advantages

Norman Yeend

• Very high kill rate. • Selective (i.e. only bitou bush is controlled). • No soil disturbance. Applying the method Cut through the stem horizontally as close to the ground as possible with a bush saw, secateurs, loppers, chainsaw or brush-cutter. A horizontal cut is important so the herbicide does not run off. Immediately (within 15 seconds) apply herbicide to the cut surface of the stump,

42

Disadvantages • Labour intensive. • Time consuming when dealing with large infestations. • Cannot be used in wet weather. • May require training. • Not applicable in some situations (e.g. on steep slopes or near cliffs without trained contractors).

Stem injection Also called drill-and-fill, stem injection delivers herbicide directly to the sapwood. Always read and follow all directions on the herbicide label and relevant permit, including usage restrictions (e.g. use is often restricted in wet weather).

Herbicide dyes can enable you to see where you have treated. Follow-up will be required to target recruitment of bitou bush seedlings. Timing Any time of the year (weather permitting). Most effective when bitou bush is actively growing so that herbicide is rapidly transported to the roots. Suitability of the method Plant age – old, established bitou bush plants with thick woody stems that are too thick to cut-and-paint (e.g. >10 cm diameter).

Kym Smith

Habitat type – any; particularly useful for plants that are entwined around native trees and shrubs in woodlands and rainforests (where removing the mass of bitou bush plants may damage the canopy of natives). Applying the method Herbicide movement Use a cordless drill or hand drill to make holes Bark Drilled around the base hole Sapwood of the trunk, no more than Heartwood 50 mm apart. Holes should go no deeper than the sapwood layer, as the heartwood layer will not transport herbicide around the plant.

Drill holes at a 45° angle (downwards) to aid herbicide retention by creating a reservoir. This will increase absorption by the plant. Alternatively, a chisel and hammer can be used to make a 45° angled incision down into the stem. Ensure the flat side of the chisel is facing upwards. Inject the herbicide within 15 seconds of drilling/cutting the hole, using a squeeze bottle or plastic syringe. Do not overfill the holes. Excess herbicide can contaminate the environment. Injection guns are also available that can drill the hole and deliver a precise amount of herbicide at the same time.

Size of infestation – isolated infestations, scattered plants or infestations that cover a small area. Advantages • • • •

Very high kill rate. Selective (i.e. only bitou bush is controlled). No soil disturbance. Gradual defoliation of the plant in situ may have benefits for the protection of native species. • Also suitable for targeted control over a small area, when other methods are unacceptable (e.g. around threatened species). Disadvantages • Labour intensive. • Time consuming when dealing with large infestations. • Dead bitou bush vegetation remains in situ which may become a fire hazard. • May require training. • Not applicable in some situations (e.g. on steep slopes or near cliffs without trained contractors).

43

SECTION 4:

Control methods C

Scrape-and-paint This method involves scraping away a small section of the bark and applying herbicide directly onto the sapwood. It is rarely used in the field to control bitou bush, but has been proven to be effective where used. Always read and follow all directions on the herbicide label and relevant permit, including usage restrictions (e.g. use is often restricted in wet weather).

Follow-up will be required to target recruitment of bitou bush seedlings. Timing Any time of the year (weather permitting). Most effective when bitou bush is actively growing so that herbicide is rapidly transported to the roots. Suitability of the method Plant age – old, established bitou bush plants with thick woody stems that are too thick to cut-and-paint (e.g. >10 cm diameter). Habitat type – any; it is particularly useful for plants that are entwined around native trees and shrubs in woodlands and rainforests (where removing the mass of bitou bush plants may damage the canopy of natives). Size of infestation – isolated infestations, scattered plants or infestations that cover a small area. Advantages

Stephen Booth

• • • • Applying the method Using a knife or sharp axe head, scrape a 15 cm long length of bark off the main trunk running vertically along the trunk. Only scrape off enough bark to expose the sapwood (i.e. a few millimetres deep). Immediately (within 15 seconds) apply herbicide to the exposed surface (sapwood) using a squeeze bottle, sponge-topped applicator bottle or paint brush. Herbicide dyes can enable you to see where you have treated. Depending on the diameter of the stem, multiple scrapes may be required around the circumference of the stem. Place a few centimetres space between each scraped patch to ensure maximum herbicide uptake without ringbarking (removing a complete ring of bark and conductive tissue from the stem prevents herbicide transport to roots).

44

Very high kill rate. Selective (i.e. only bitou bush is controlled). No soil disturbance. Also suitable for targeted control over a small area, when other methods are unacceptable (e.g. around threatened species). • Gradual defoliation of the plant in situ may have benefits for the protection of native species. Disadvantages • Labour intensive. • Time consuming when dealing with large infestations. • Dead bitou bush vegetation remains in situ which may become a fire hazard. • May require training. • Not applicable in some situations (e.g. on steep slopes or near cliffs without trained contractors).

Foliar spraying

Phil Maughan

Foliar spraying is the application of herbicide solution to the leaves of a plant in the form of a fine spray. There are a number of foliar spray application techniques available, the selection of which depends on the: • Size of and access to the infestation, • Access to equipment and chemicals, • Herbicide label recommendations/permits, • Training and/or contractor availability, • Funds, and • Specifics of the technique relevant to your goal and site conditions.

Foliar spray application techniques use herbicides diluted in water. A range of other chemicals may also be added (e.g. penetrants, adjuvants, surfactants, wetting agents, etc.). The application rate, volume and concentration of herbicide in water varies depending on the application technique. For example, backpack spraying and vehicle mounted spray rigs apply a high volume of liquid with a low concentration of herbicide (e.g. 1:100 for glyphosate 360 g/L), while the splatter gun technique uses a low volume of liquid with a high concentration of herbicide (e.g. 1:29 for glyphosate 360 g/L). Always read and follow all directions on the herbicide label and relevant permit, including usage restrictions (e.g. use is often restricted in wet weather).

Jeff Thomas

The foliar spray application techniques available to control bitou bush include: • Low-pressure spraying using a hand-held container or backpack sprayer (with either a wand or hand gun), • High-pressure spraying using a vehicle mounted spray rig and hand gun (e.g. pump powered Quikspray® unit), • Low-volume, high-pressure splatter gun (using either manual or gas powered equipment), • Aerial spot spraying using a helicopter, or • Aerial boom spraying using a helicopter. No bitou bush-selective herbicide currently exists, so care needs to be taken not to damage desirable native vegetation by off-target spraying, over-spraying or spray drift. Applying the method Determine the training required and ensure you have been suitably trained. Select an appropriate herbicide and application technique. Read the herbicide label carefully and follow the instructions and any required conditions on the permits. Ensure you have adequate personal protective equipment. When spot spraying you must ensure that the plants are sprayed thoroughly, wetting all foliage. On unstable soils, spraying areas in a patchwork fashion (e.g. leaving parallel strips unsprayed along sand dunes) can aid stabilisation and the transition to restoration.

45

SECTION 4:

Control methods C

Put in place measures to minimise spray drift and off-target damage. Consider weather conditions and only apply herbicide in accordance with the label (e.g. avoid spraying when rain is forecast). Herbicide dyes enable you to see where you have sprayed. Follow-up will be required to target recruitment of bitou bush seedlings.

• • • • •

High kill rate. Large areas can be treated quickly. Not labour intensive. Can be used in steep or erosion prone areas. Minimal soil disturbance as plants are left to die in situ.

Timing

Disadvantages

Any time of the year (weather permitting). Most effective during the peak flowering period (i.e. in winter) as bitou bush is actively growing so herbicide is rapidly absorbed through the leaves and transported to the roots. However, it is not as effective if plants are stressed by hot, dry, cold, wet or other extreme weather conditions.

• • • • •

Suitability of the method Plant age – all plants. Habitat type – any except where prohibited by legislation (e.g. threatened species legislation). Size of infestation – the area treatable is dependant on the application technique, for example, a backpack spray unit is only suitable for small infestations or isolated plants. Larger areas can be treated with vehicle mounted spray units (e.g. quad bike, tractor or 4WD). Protecting native species Make sure you thoroughly check the area for native plant species prior to spraying, particularly for threatened species or those identified as being at risk in the NSW Bitou Bush Threat Abatement Plan. If native species occur in the area to be sprayed, clear an area (buffer) of bitou bush away from such species using handweeding techniques prior to herbicide applications. Alternatively, small native plants can be covered with hessian or cardboard prior to spraying – ensure that these coverings are removed once the herbicide has dried. If a native plant is inadvertently sprayed, remove the affected leaves or immediately rinse off the herbicide with water.

46

Advantages

Risk of off-target damage. Cost of spray equipment. Cannot be used in wet weather. May require training. Successful control requires the plants to be free from coatings of salt-spray, water, dust or other vegetation (e.g. vines). • Limitation on individual methods (e.g. backpack spraying requires the regular refilling of the tank, which increases time and costs and there may be long walking distances from the spray site to the nearest water supply). Accessing sand dunes to spray bitou bush Quad bikes (if registered for this use) can be used to drive over vegetated sand dunes to gain access to the hind dune to treat bitou bush. In a few instances a 4WD tractor with caterpillar tracks (or a wide-wheeled tractor) has been used. Caterpillar tracks or large tyres have the least impact on vegetation, and are least likely to cause sand compaction and erosion. Volunteers at Lake Cathie Landcare have registered a small tractor to transport their mulching machinery which has proved more useful than a quad bike for some areas, and easier for the community group to register. Off-target damage must be evaluated carefully before you drive over sand dunes, even though stable vegetation such as coastal wattle can recover within a short period of time. Alternatively, see Mechanical methods for ways of creating access pathways. Make sure the vehicle is properly registered as there is no insurance without registration.

Splatter gun Splatter guns administer large droplets of highly concentrated herbicide solution to target plants from a distance of 6–10 m. Due to the high concentrations of herbicide used, only a small amount of solution per plant is required for maximum effect; the herbicide translocates throughout the plant. Always read and follow all directions on the herbicide label and relevant permit, including usage restrictions (e.g. use is often restricted in wet weather).

at intervals of 1–2 m. Then splatter a strip at the top and bottom of each plant, creating a square ‘lattice’ pattern. Follow-up will be required to target recruitment of bitou bush seedlings. Timing Any time of the year. Most effective when bitou bush is actively growing (at peak flowering in winter) so that herbicide is rapidly transported to the roots. However, it is not as effective if plants are stressed by hot, dry, cold, wet or other extreme weather conditions. Suitability of the method Plant age – small to large mature plants; limited suitability for seedlings.

Marion Winkler

Habitat type – any; particularly within dense vegetation that is difficult to access using vehicles, or on steep slopes and cliff edges. Splatter gun is also useful on sand dunes where sand is clumping over bitou plants and part of the plant is layered under the sand. Hand powered splattergun equipment

Size of infestation – heavy infestations or scattered bushes. Advantages

Marion Winkler

• Equipment is lightweight and portable. • An entire plant can be treated with only a small amount of spraying effort. • Requires minimal use of water. • Very high kill rate for mature plants. • Large areas can be treated quickly. • Easy to operate in difficult terrain. • Minimal soil disturbance. • Reduced chance of spray drift. Gas powered splattergun equipment

Applying the method Herbicide concentrations for splatter guns differ from that of normal foliar spray guns. Splatter herbicide onto individual bitou bush plants in long arching vertical stripes placed

Disadvantages • Cost of spray equipment. • Off-target damage can be amplified because of the concentrated nature of this technique. • Cannot be used in wet weather. • May require training.

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SECTION 4:

Control methods C

Aerial boom spraying Treating plants in difficult-to-access locations – cliff faces

Aerial boom spraying refers to the broad scale application of herbicide from a boom spray rig attached to a helicopter flying at very low altitude (i.e. 5 m above bitou bush plants).

1. Several people have used extension devices with foliar spray apparatus to reach plants in hard to access areas (e.g. steep area and cliff faces). These devices include an aluminium extension pole (similar to a swimming pool cleaner handle) with a sprayer attached to the end.

Herbicide solution is then broad acre sprayed over vegetation from a long (12 m wide), medium (8 m wide) or mini (4 m wide) boom. This technique (for bitou bush) was developed in New South Wales in the early 1990s after substantial trials with both bitou bush and native species (see case study Developing aerial spraying techniques in natural ecosystems in Section 7 for more information). These trials showed that if used in winter, a very low rate of herbicide (e.g. 2 L/ha) could control bitou bush while having limited impacts on native species. However, the actual herbicides used in aerial boom spraying are not strictly selective for bitou bush and therefore all plant species may potentially be affected.

2. Machines with specialised attachments may also be used such as the pictured long armed tractor sprayer. 3. Another method used in steep areas is the splatter gun technique (see page 47) applied during abseiling into difficult-to-reach areas. Splatter guns can be used while abseiling because the equipment is lightweight, easy to use in difficult situations and accurate at a distance.

A permit and specialised training is required for aerial spraying – always read and follow all directions on the herbicide label and relevant permits. Applying the method

48

Terry Inkson, Great Lakes Council

Marc Stettner, Apunga Ecological Management

Matt Craig

Dallas Gooding

Aerial boom spraying should be incorporated into a broader integrated weed management program and not used in isolation. Plan to

Aerial boom spraying along a beach from a 12 m wide boom

commit to long-term control over the entire treatment area as follow-up control using other techniques will most likely be required. If you can’t afford to manage the follow-up work in consecutive years, then you should reconsider the size of the area you intend to treat. Best practice guidelines for aerial boom spraying of bitou bush in New South Wales have been produced and should be used in any aerial spray program. These guidelines are in the form of a checklist of activities in chronological order from preliminary planning through to post control. Best practice guidelines for aerial spraying of bitou bush in New South Wales can be downloaded from www.environment.nsw.gov. au/pestsweeds/BitouSprayingGuidelines.htm Best practice guidelines for

aerial spraying of bitou bush in New South Wales

Elizabeth A. Broese van Groenou and Paul O. Downey

0

Timing Aerial boom spraying is best undertaken in winter, when bitou bush plants can be killed while limiting off-target damage to native plants. Suitability of the method Plant age – mature plants, but is also effective on young plants. Habitat type – Ideal for cliff faces, rocky headlands and other hard to access areas and where bitou bush is the dominant plant, particularly where bitou bush does not grow under a native canopy; native plants are more susceptible to off-target damage when a protective bitou bush canopy is absent.

Aerial boom spraying in littoral rainforests in New South Wales is not legally permitted as it is an Endangered Ecological Community. Size of infestation – monocultures, spread over large areas. Advantages • Large areas can be treated in a single event. • Cost per unit area is low. • Plants in otherwise inaccessible areas can be controlled. • Detailed best practice guidelines developed. Disadvantages • Significant planning and extensive community consultation and notification required beforehand. • Requires the closure of the areas to be treated from public access. • Labour intensive before and on the day of operation. • Very weather dependant, which may delay the operation. • Helicopter availability and access required. • Use restricted to winter months. • Off-target damage possible. • Contractor only. • Public concerns over aerial spraying use. • Extensive follow-up is required. Impact to native species Information continues to be gathered on the effect of aerially applied herbicide on native species. Eighty-three species (natives and weeds) have now been assessed for their response (or lack of response) to metsulfuron methyl as applied from aerial boom spraying, and 220 species have been assessed for their response to glyphosate application. Lists of the species are available within the aerial spraying guidelines, or can be downloaded from www.environment.nsw.gov.au/ pestsweeds/BitouSprayingGuidelines.htm. See Developing aerial spraying techniques in natural ecosystems for bitou bush case study on page 95.

49

SECTION 4:

Control methods C

Aerial spot spraying

Many aspects of the aerial boom spraying guidelines also apply here (e.g. notification, helipads, limiting public access etc.).

Aerial spot spraying is a relatively new foliar spraying application technique. It uses the ground based spot spraying technique, but applies it from a helicopter rather than a backpack or spray rig. This technique was developed by the NSW National Parks and Wildlife Service and uses a modified spray rig and hose and nozzle assembly protected by a cone which is suspended from beneath the helicopter. Aerial spot spraying enables treatment of individual plants or small clumps that may not otherwise be treatable due to limited or difficult access (e.g. on cliff faces).

Follow-up will be required to target recruitment of bitou bush seedlings which may require repeated aerial application. Timing Aerial spot spraying is best undertaken in winter, when bitou bush plants can be readily controlled, while limiting off-target damage to native plants. Mature plants are also easiest to locate and identify when flowering in winter. Suitability of the method

Aerial spot spraying is used to treat individual plants with ground based spray rates, as opposed to aerial boom spraying which uses a specific aerial spray rate of herbicide applied across a large area.

Plant age – mature plants.

To apply this technique you need a permit and a specially trained pilot – always read and follow all directions on the herbicide label and the permit.

Size of infestation – isolated bitou bush plants.

Habitat type – anywhere bitou bush does not grow under a canopy. Particularly useful for treating plants on cliff edges and steep slopes.

Advantages • Plants in otherwise inaccessible areas can be controlled. • Very effective control can be achieved. • Decreases safety issues with regards to treating plants on steep slopes or cliff faces.

NSW DECC

NSW DECC

Disadvantages

Spot spraying using a conical device suspended from a helicopter

Applying the method The pilot/co-pilot selects a specific bitou bush plant. The helicopter hovers over it and lowers the cone so it is as close to the target plant as possible and then the operator pulls the trigger. Herbicide covers the plant with the aid of gravity and downward wind from the rotors.

50

• The hose can sway and thus it may be difficult to treat the right plant. • Off-target damage in immediate area may be high. • Highly weather dependent, but less so than aerial boom spraying. • Public concerns over the use of aerial spraying. • At present this method is only employed by the NSW National Parks and Wildlife Service. • Not suitable for treating large areas. • Specialised equipment. • High cost. • Extensive planning required.

Other control methods Mechanical methods Mechanical methods of control involve the use of machinery such as brushcutters, or heavy machinery such as tractors, mulchers and excavators. While not commonly used in the control of bitou bush, mechanical methods have been used in a few instances. Heavy machinery can be used to control bitou bush plants (by slashing or mulching the standing biomass) or to create access paths into areas that are otherwise difficult to reach for spraying. However, the use of such machinery can have negative effects on native plant communities and may lead to erosion. Mechanical methods using slashing (mowing) attachments on a vehicle can be used on both live and dead bitou bush plants to reduce the biomass of standing plants, enabling faster decomposition and reducing the chance of arson in sprayed dead bitou bush. Slashing live plants also prevents further seeding. When used on live plants, the cut stumps may resprout and will need to be treated with herbicide before the next flowering period. If you are using heavy machinery, make sure it is registered appropriately and that you are licenced to use all equipment.

used with a tractor or purpose built machine, which is then driven over the infestation. Dead bitou bush can be mulched on site with a hand-fed mulching machine (see page 67). Alternatively, a front end loader/backhoe can be used to deconstruct dead bitou bush material after it has been sprayed. The teeth of the bucket are turned facing the operator and the outer section of the bucket is used to flatten the bitou bush. The results are an instant rough mulched layer with less resprouting from bitou bush stumps. There will be little regrowth from the stumps of the original infestation if it has already been sprayed, however follow-up spraying of germinating seedlings is necessary. With all vehicular movement there is a risk of transporting undesirable plant species via seed, so ensure correct vehicle hygiene procedures are implemented prior to and directly after any control. Timing Any time of the year, except during fruiting periods to prevent the machinery spreading bitou bush seeds. Suitability of the method Plant age – mainly mature adult plants.

Reece Luxton, Clarence Valley Shire Council

Habitat type – mechanical slashing from a vehicle is not selective so has limited use in natural areas as it can damage native vegetation. It is also not recommended on highly mobile sand dunes. Be aware of areas that are sensitive and where the use of heavy machinery may increase the risk of erosion (e.g. only use on stable soils). This technique also has limitations in steep or hilly terrain. Mechanical methods (e.g. slashing) can be used to create access pathways through bitou bush monocultures

Applying the method Heavy duty slashing equipment can simultaneously fell bitou bush plants and cut them into pieces. Slashing attachments can be

Size of infestation – mechanical slashing from a vehicle is not suitable for broad scale control of bitou bush, but is applicable within monocultures of bitou bush on a scale where follow-up is feasible. Advantages • Can open up areas for further control.

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SECTION 4:

Control methods C

• Less labour intensive than manual or chemical control for large infestations. • Can be cost-effective for large infestations. • Herbicides are not needed pre-slashing. Disadvantages • • • •

Follow-up effort required. Damages desirable vegetation. Can lead to erosion and/or soil compaction. Can open up areas quickly which may have adverse effects (e.g. increased public access or erosion). • Machinery is expensive and can only be used by trained operators. • Not applicable in most situations.

In the event of a wildfire in bitou bush infestations, all effort should be taken to capitalise on the depletion of the bitou bush seed bank. Failure to do so may lead to bitou bush outcompeting germinating native species. Incorporate contingency planning in your management plan for follow-up control for several years after a wildfire.

Daintry Gerrand

52

Mike Dodkin

While it may look as though the problem has grown worse when you see a carpet of seedlings after a fire, this mass germination will significantly deplete the seed bank, but you must ensure follow-up.

Spray bitou bush prior to burning to establish the fuel load

Involve the local fire authority when planning and carrying out a prescribed burn

Hillary Cherry

Fire can be used to control bitou bush, but must be part of an integrated control strategy. Fire may be very advantageous as it can kill bitou bush plants and seeds in the top 2–3 cm of soil. Fire may also stimulate germination of the soil seed bank, thus helping to deplete the seed bank more quickly. The success of fire in controlling bitou bush is highly dependent on commitment to treat the resulting germination before young plants flower and set seed. Also, even the hottest fire may not stimulate seeds below 3–8 cm, as soil is a good insulator.

Jeff Thomas

Fire

Capitalise on native species germination after fires – remove bitou bush when it is still small and young

Applying the method You need to consult with the local fire authorities and council in your area before considering a burn and you will need a permit to undertake a prescribed burn. Determine if fire is appropriate, practical or possible at your site (e.g. what will be the response of native vegetation and other weeds at the site? What are the costs versus benefits of burning/not burning?). Develop a fire management plan in consultation with all relevant stakeholders and authorities. In many instances you may need to spray the bitou bush beforehand, as ‘green’ bitou bush does not burn readily. After a fire, a protective crust is formed on the soil surface. This crust reduces erosion and retains soil moisture. Working in a newly burnt area can disturb the protective crust and cause soil compaction. Therefore delay the initial follow-up work until at least three months after burning. Commitment to follow-up control is essential, ensure it occurs before first flowering (e.g. within six months of the fire). Follow-up needs to occur regularly each year for several years to gain the maximum benefit from the fire, so ensure the area you burn is not larger than the area you can manage to follow-up. Fire may also be beneficial for restoration (see Section 5 for further information). Note: It can be more efficient to spray regrowth after a fire, however research indicates that handweeding (or targeted spot spraying) may cause less damage to regenerating native species (French et al. 2008).

Timing Dependent on the issuing of a permit and weather conditions. Consult the relevant fire authorities and council. Suitability of the method Plant age – all plant ages. Habitat type – fire is not suitable in all situations (e.g. rainforests, exposed sand dunes which may erode, or within some Endangered Ecological Communities or near threatened species). Size of infestation – medium to large infestations where follow-up control is ensured across the entire area. Advantages • Can deplete the soil seed bank via seed mortality and germination. • Stimulates germination of some native seedlings which can aid restoration. • Can open areas to access. • Planned use of fire can reduce the threat of undesirable arson attacks. Disadvantages • Not suitable in all vegetation types. • Fire can kill native plants as well. • Follow-up of mass bitou bush recruitment is time consuming and expensive. • May increase erosion. • Other weeds may invade after control. • Weather dependent. • Extensive planning required. • It is not a method that community groups can carry out on their own.

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SECTION 4:

Control methods C

Iluka Bluff and the successful use of fire to control bitou bush

Growth from native plantings is extensive on Iluka Bluff and the surrounding area, and the area has been completely transformed to a thriving native plant community in less than 10 years.

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Jeff Thomas

Site with bitou bush before control, 1997

Jeff Thomas

Six months after burn, 1998

The site in 2000

Jeff Thomas

Iluka Bluff had been infested with bitou bush for many years. The rocky headland, bounded in the west by littoral rainforest and in the east by coastal beaches, was covered in a near monoculture of bitou bush plants. In August 1997, the area was sprayed, leaving bands of green bitou bush as firebreaks around the few remnant trees in preparation for a controlled burn. The dead bitou bush plants were burnt three months later by NPWS staff, and the bare area brush-matted. With the assistance of Conservation Volunteers Australia and Landcare volunteers, initial plantings occurred six months later, after an assessment of soil seed bank regeneration. In June 1998, staff controlled a dense carpet of bitou bush seedlings, which were approximately 50 cm tall; few plants had commenced flowering. Subsequent follow-up has been minimal, although selective treatment of other weeds such as Sida rhombifolia, Solanum sp. and Eleusine indica was required to promote native regeneration in the first two years. Maintenance weeding in the area continues under the guidance of a very committed community group with NPWS support.

Jeff Thomas

Fire has been used successfully to control bitou bush on the headland at Iluka Bluff on the North Coast of New South Wales. The successful restoration was based on using fire in a manner suitable to the landform and through extensive long-term commitment to follow-up control by community members and the NSW National Parks and Wildlife Service (NPWS) staff.

The site in 2008

Biological control

Brief history

Biological control (biocontrol) is the use of a weed’s natural enemies (biocontrol agents) to suppress a weed population. The aim of biological control is to: • Suppress plant vigour, • Reduce seed production, • Slow plant growth, and • Reduce the density of the weed infestation. For more information on biological control see the CRC for Australian Weed Management website www.weedscrc.org.au/ weed_management/biological_control.html.

A biological control program to combat bitou bush and boneseed was established in 1987 which examined the insects that attacked these plants in their native South Africa to determine potential effectiveness in Australia. Following extensive host-specificity testing and approvals from AQIS, several insects have been released. To date, four of the six insect species (agents) released on bitou bush in Australia have established, with the bitou tip moth (Comostolopsis germana) and the bitou seed fly (Mesoclanis polana) now widely distributed and causing damage (see Downey et al. 2007 for more information).

Bitou tip moth

At some sites bitou tip moth is attacked by two native parasites (up to 50% of the moth larvae can be killed), but in many areas it is having a significant impact on the flowering and seed production of bitou bush (Holtkamp 2002).

CSIRO (left and right), Tom Morley (centre)

The bitou tip moth (C. germana) is a foliage-feeding insect and was the first agent to be released on bitou bush in 1989. It destroys the developing leaves, buds and flowers of bitou bush plants by feeding on new stem tips. The tip moth is now widespread in New South Wales.

Larva

Adult

Plant damage

Larva

Adult

Plant damage

The bitou seed fly (M. polana) is a seed-feeding insect that lays its eggs into developing flower buds. The larvae feed on developing flowers and seeds, causing major reduction in seed production. The seed fly is now widespread, with flies observed from Fraser Island in Queensland to Tathra in southern New South Wales. Seed production of bitou bush has been halved in many areas.

Jessica Schoeman (left), Tom Morley (centre and right)

Bitou seed fly

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SECTION 4:

Control methods C

Bitou leaf roller moth

Reece Luxton, Clarence Valley Shire Council

Royce Holtkamp, NSW DPI

The leaf roller moth has only established at a few sites in New South Wales. Studies show that these moths establish most easily on bitou bush plants on headlands, and thus new release sites should be on headlands rather than dunes.

Reece Luxton, Clarence Valley Shire Council

The bitou leaf roller moth (Tortrix sp.) is a foliagefeeding insect. It destroys the developing leaves, buds and flowers of bitou bush plants by feeding on the new stem tips. The larvae roll leaves together around a stem tip, forming an enclosed shelter in which they feed on the developing leaves, buds and flowers.

Larval feeding shelter (top), adult (left), plant damage and larva (right)

The bitou tortoise beetle (Cassida sp.) is a leaf-feeding insect that attacks older leaves, which complements the damage caused by the bitou tip moth. It was first released on the Central Coast of New South Wales in 1995. However, it has failed to establish widely despite several attempts and its natural spread appears to be very slow.

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Royce Holtkamp, NSW DPI (both)

Bitou tortoise beetle

Larva

Adult

Biocontrol agents and other control techniques

Redistribution of bitou bush biocontrol agents

Biocontrol alone will not remove bitou bush. These insects need to be used as part of an integrated approach to bitou bush control. When developing your control program where these insects have established, leave patches of bitou bush as nurseries so the insects can rapidly attack any bitou bush recruitment following control. Conventional control methods may still be undertaken.

Anyone can help in the redistribution of bitou bush biocontrol agents in the field by deliberately moving insects to a new location. The leaf roller moth is relatively easy to locate and redistribute. Given that the tip moth and seed fly are already widespread, redistributing them is of limited use.

Centre for Learning Innovation

Firstly you need to be familiar with all the biocontrol insects, then collect as many as you can find, up to about 100 if possible (it is best to collect numerous individuals, to ensure you have a collection of breeding pairs and genetic variety). The leaf roller moth and tip moth can be easily confused in the larvae stage so you might need to wait to confirm identification when they become adults.

Carefully transport the larvae directly to a new site prior to any wilting of the bitou bush branches, and lay branches over uninfected bitou bush plants. Be sure to place them in the same situation (i.e. for the leaf roller, lay them onto newly forming stem tips). The larvae are mobile and quickly move off the dying branches onto the new food source. Notify the land manager or local council weeds officer if you plan to redistribute bitou bush biological control agents so that a record can be kept of how far the insects have been transported. Weed Warriors Weed Warriors is a program developed to engage school children in weed issues. Students rear biocontrol agents in the classroom and then release them on weed infestations in their community. Your local primary school can become involved in this program by contacting the Weed Warriors coordinator in your state (see Section 8). A Weed Warriors program has recently begun for bitou bush using the bitou leaf roller moth in New South Wales.

Centre for Learning Innovation

Larvae of the leaf roller moths can be found on the tips of stems, inside a white webbing (the larval feeding shelter) or crawling over the tip foliage or stems. Cut leaves or branches carrying the larvae off the infected plant, and store these branches in a cool, shaded container, for example an esky, prior to transportation.

Weed Warriors is an extensive education program involving school children

Leaf roller (Tortrix sp.) caterpillar

In addition to Weed Warriors, an integrated educational resource called Weeds Attack! is available to teach children about biocontrol and other weed issues. See the case study on Weed Warriors and Weeds Attack! on page 80 for further details.

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SECTION 4:

Control methods C

Comparison of control methods Once you have identified appropriate methods for your habitat type (see page 33 and the specific control methods), use the summary table below to compare the advantages between methods to finalise your decision. Control method

Advantage / disadvantage

Stem injection Hand Cut-and- / Scrape- Foliar weeding Crowning paint and-paint spraying

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Splatter gun

Aerial boom spraying

Aerial spot Mechanical spraying methods

Fire

Biological control

Page

34

35

42

43 / 44

45

47

48

50

51

52

55

Easy to use (minimal training required)

9

9

9

9

}

9

8

8

8

8

9

Minimal equipment required

9

9

9

9

8

8

8

8

8

8

9

Low or no off-target impacts

9

9

9

9

8

8

8

8

8

8

9

Low level of soil disturbance if done carefully

}

9

9

9

9

9

9

9

8

8

9

Suitable for community groups

9

9

9

9

}

}

8

8

8

8

9

Covers large areas quickly

8

8

8

8

9

9

9

9

9

9

n/a

Can be used in all weather

9

9

8

8

8

8

8

8

8

8

9

Follow-up required

9

9

9

9

9

9

9

9

9

9

9

Enables access for follow-up control

9

9

9

8

8

8

8

8

9

9

8

No or limited growth if applied properly

9

9

9

9

9

9

9

9

8

8

n/a

Applicable in inaccessible areas

8

8

8

8

}

}

9

9

8

8

9

Bitou bush dominance replaced gradually

}

9

}

9

}

}

8

8

8

8

9

9

Yes.

8

No.

}

Dependant on situation and scale of infestation – see specific description of the method along with the advantages/disadvantages of the method in respective environments before using it.

n/a

Not applicable.

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Control methods - Office of Environment and Heritage

Control methods Plan before you control Key control considerations Control method decision matrix 32 33 34 Manual methods Chemical methods Other co...

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