Skeleton weed Management guide - Program and protocols

Page last updated: Wednesday, 27 November 2019 - 12:20pm

This Management Guide has been designed to assist landholders and increase their capacity to manage and eradicate skeleton weed infestations on their properties and to prevent further spread within the State. Section 1 - Program protocols and skeleton weed information.

Without the coordinated program aimed at controlling spread, skeleton weed would now be much more abundant and widely established throughout the cereal growing areas.

Skeleton weed is a declared plant which can reduce crop yields by competing for moisture and nutrients (mainly nitrogen).

Declaration categories and management implications

Skeleton weed is declared under section 22(2) of the Biosecurity and Agriculture Management Act 2007.





Whole of the State except Narembeen and Yilgarn

  • Eradicate infestations; destroy plants and prevent propagation each year, until no plants remain
  • Prevent the spread of seed or plant parts
  • Summer search is required 
  • Winter control is required


Narembeen and Yilgarn

  • Manage infestations to prevent the spread of seed or plant parts
  • Summer search is required
  • Treat plants to prevent seed set
  • Winter control is required to receive search assistance

​The Skeleton Weed Program

The Skeleton Weed Program is a coordinated approach to manage skeleton weed in Western Australia. It is delivered by the Department of Primary Industries and Regional Development (DPIRD) under arrangement with the Grains, Seeds and Hay Industry Management Committee. The Committee acts under the Biosecurity and Agriculture Management Industry Funding Schemes (Grains) Regulations 2010 to manage prioritised pests affecting the grains industry.

Services provided under the program are only available to landholders who contribute to the Grains, Seeds and Hay Industry Funding Scheme through the sale of grain, seed or hay. Landholders not under the scheme but who have skeleton weed on their properties are still required to meet their obligations under the program but at their cost

All landholders need to prevent the movement of seed and/or root fragments from their properties in produce (grain, seed and hay),
wool, machinery and vehicles.

What the program provides to assist landholders 

  • Identification of suspected skeleton weed plants.
  • Technical assistance and advice for the eradication and/or management of skeleton weed on your property.
  • Assistance and advice on summer and winter herbicide application.
  • Mapping of infestations.
  • Assistance with searching new skeleton weed finds and previously infested paddocks.
  • Support from DPIRD and Local Action Group staff.


Assisting Western Australian landholders to eradicate skeleton weed and to prevent its further spread within the State. 


  • Improve landholders’ ability to find and eradicate skeleton weed.
  • Increase landholders’ awareness of skeleton weed as a highly undesirable weed.
  • Widely publicise descriptions and pictures of skeleton weed to help landholders identify infestations.
  • Inform landholders about the most up-to-date techniques available for the management and eradication of skeleton weed.
  • Encourage local grower groups, Local Action Groups (LAGs), to participate in cooperative surveillance and reporting of infestations.
  • Encourage LAGs to assist in the management and eradication of skeleton weed in their local areas.
  • Implement practical compliance regimes in affected areas.
  • Provide landholders with incentives to report infestations.
  • Provision of winter control treatments where landholders are compliant with program requirements.

The Program has very effective management options
for eradicating skeleton weed

Local Action Groups (LAGs)

A LAG is a network of local farmers in a district affected by skeleton weed, and who have a shared interest in helping other landholders around them cope with the issues skeleton weed presents.

Each LAG applies annually to DPIRD for funds from the approved Skeleton Weed Program budget which is endorsed by the Grains, Seeds and Hay Industry Funding Committee. They aim to promote awareness of skeleton weed, support local landholders with skeleton weed and assist them with management and eradication.

They liaise between landholders and DPIRD to provide input into management of local non-compliance issues and formulate local/regional strategies to deal with skeleton weed within the framework of the state-wide program. Some groups also appoint a LAG Coordinator to work with landholders and in conjunction with DPIRD to undertake operational activities.

Local Action Groups are designed to provide you with additional support. Check with your local DPIRD office for the name of your nearest LAG representative.

There is an extensive local support network for you to call on to assist you identify and help manage skeleton weed effectively

Finding information and advice

Communication with your local DPIRD office, your Local Action Group and your neighbours is integral to achieving skeleton weed eradication on your property.

There is a lot of information available to landholders who find skeleton weed on their land, and a lot to remember, too. If you are unsure of what to do, there are several avenues for you to follow.

In the first instance, your local DPIRD or LAG office can assist. You will be given reference material containing all the information you need to manage and eradicate skeleton weed from your property. Take the time to read it, and make a note of any additional questions that come to you later.

Regular communication with your local DPIRD officer and/or LAG coordinator is essential to ensure you are aware of all your obligations, and what support the program provides. Most of the information given to you by your local DPIRD officer and/or LAG coordinator is also available on the DPIRD website, including this Management Guide.

If you live in an area where skeleton weed is prevalent, neighbours may be able to assist you.
You may even find yourself in a position to share knowledge with those who have not yet encountered skeleton weed themselves.

Visit DPIRD’s  website:

Skeleton weed at a glance

Skeleton weed (Chondrilla juncea L.) is a perennial daisy-like plant that develops from a rosette into a sparsely-leafed, erect plant of up to 1m tall. Erect, branched stems, with little or no foliage, are produced from early October, giving the plant an untidy-look. The rosette and the adult plant exude sticky white sap when cut.

skeleton weed rosette

Rosette leaves vary in shape, but barbed lobes remain a key feature

Rosette leaves 5–10cm long present hairless barb-like lobes that point backwards towards the centre of the rosette.

A rosette can be sparsely or densely-leafed, depending on plant age, soil type and how extensive the root system has become. In late spring, stems form and the rosette usually dies off, though a healthy rosette with a well established root system may persist well into summer if there is adequate soil moisture.

Summer rain or high residual soil moisture will encourage old rosettes to re-emerge, even after chemical treatment.

skeleton weed mature plant

Can have prominent leaves along the stem in good growing conditions

Mature plants have an extensive root system. The tap root can be over 2m long and the lateral roots can radiate up to 50cm from the main tap root.

The plant develops one or more wiry-branching hairless stems growing up to 1m tall. Stems present stiff, downward-pointing bristles at the base. Leaves, if present, are narrow and elongated. Plants can live for several years; stems dying off in late summer as seeds mature. Summer rain may cause regeneration and further seed production.

Lateral root fragments as small as 5 to 10mm can generate new plants. These fragments are usually dragged by farm machinery.

skeleton weed flower

Each petal presents small teeth across its blunt tip

Flowers are bright yellow and daisy-like with 9–12 petals. Individual flower heads are about 20mm wide. Flowers appear on short stalks, in the angle between the plant stem or branch and a leaf or bract. They may occur singly or in clusters of two to five flowers.

Flowers are found along the full length of the branches and at the tip of the main stem, appear from December to May.

skeleton weed seeds

A healthy, mature plant produces 10000 to 20000 seeds

Seeds are arranged in ten or eleven seeds per flower. Each seed is 5mm long, with a white parachute attached to the top (to aid wind dispersal). Seeds are grooved, acting like ‘teeth’ to catch on wool, hair or fur.

Seeds are fragile and susceptible to mould and bacteria (causing desiccation in unfavourable weather conditions), and predation by insects and birds.

If adequate summer rainfall occurs, seeds germinate quickly, but usually die if there are no follow up rainfall events. If no rain falls during summer and the seed remains viable and survives predation, it will germinate in the following autumn or winter.

Seeds rarely survive more than 12 months under field conditions, so there is no long-term seed bank.

Skeleton weed features


Skeleton weed features


Where does skeleton weed grow?

Skeleton weed is mainly found in crop and pasture paddocks but can also be found growing in various types of environments including road verges, railway lines, industrial sites, tree plantations and bush areas.

skeleton weed in industrial yard

Mature plant growing in industrial yard

skeleton weed elongated stems

Plant with elongated stems from herbicide or frost damage

skeleton weed in crops

Skeleton weed can be difficult to spot among crops

Plants growing alonside rail line

Plant growing alongside rail line

Plants confused with skeleton weed   

Flatweed and smooth catsear (Hypochaeris spp.)

Flatweed (Hypochaeris spp.)

Hypochaeris species have more than 11 yellow petals

Flatweed is a short-lived perennial, and smooth catsear is an annual plant. Hybrids of these two species exist throughout the south of the State.
Characteristics of Hypochaeris species:

  • fleshy basal rosette with club-shaped leaves and a rounded apex
  • simple or slightly branched, semi-erect stem up to 30cm tall
  • more than 11 seeds per head that disperse with a parachute of silky hairs.


Wild lettuce (Lactuca serriola L.)

Wild lettuce (Lactuca serriola) can be confused with skeleton weed

Wild lettuce has deeply lobed leaves

A biennial plant, seen in townsites, on road verges and in paddocks.

  • stiff, prickly stem up to 1.5m tall
  • stalkless, deeply lobed or toothed, leaves, with spines along upper margins and along the lower midrib
  • pale yellow flowers borne on florets
  • lower leaves are spiny. Less divided upper leaves held upright in a north-south alignment.


Prickly lettuce (Lactuca saligna L.)

Prickly lettuce (Lactuca saligna) is often confused with skeleton weed

Prickly lettuce grows taller than skeleton weed

Prickly lettuce is a biennial herb often confused with wild lettuce. It is common in townsites and around farm buildings.

  • reaches up to 1–1.5m tall
  • very narrow leaves up to 15cm long and free of spines
  • flowers are pale yellow
  • seeds disperse by air, aided by a parachute of silky hairs.


Wild turnip (Brassica tournefortii G.)

Wild turnip (Brassica tournefortii) is often confused with skeleton weed

Wild turnip flowers much
earlier than skeleton weed

An erect annual plant up to 60cm tall.

  • basal rosette leaves with scattered hairs on the midrib and veins
  • plants with one or more stems, with soft, downward-pointing bristles
  • small, pale yellow to cream flowers 10-20mm in diameter, with four petals
  • elongated and segmented seed pods 7cm long.


Wild mustard, Indian hedge mustard (Sisymbrium orientale L.)

Wild mustard or Indian hedge mustard (Sisymbrium orientale) is often confused with skeleton weed

Seeds are contained in
smooth elongated pods

An erect annual, sometimes biennial plant, up to 1m tall.

  • presents dense, dark foliage on one or more stems, no lasting basal rosette
  • arrow-shaped leaves densely covered in imperceptible fine hairs
  • leaves on short stalks along the stems
  • yellow flowers 10–20mm in diameter with four petals
  • smooth, elongated seed pods 11cm long, splitting lengthways when mature.


Wild radish (Raphanus raphanistrum L.)

Wild radish (Raphanus raphanistrum) is often confised with skeleton weed

Wild radish flowers much
earlier than skeleton weed

An erect annual plant up to 1m tall.

  • basal rosette with broadly lobed, hairy leaves that die off before maturity
  • hairy stems with oblong and toothed or lobed stem leaves
  • pale orange or yellow to white flowers, and sometimes lilac, 30–40mm in diameter, with four dark-veined petals
  • seed pods are up to 8cm long.


Spot the difference...

comparison skeleton weed with other weeds

Surveillance for skeleton weed

Skeleton weed control requires effective monitoring and surveillance.

The effectiveness of skeleton weed control treatments depends on:

  • correctly identifying the location of skeleton weed in the paddock
  • correctly identifying the growth stage of skeleton weed.

DPIRD has been carrying out targeted surveillance since 2002 with the objective to find infestations in areas considered a high risk of having skeleton weed. This program also raises awareness of the presence of skeleton weed on high risk properties.

Since 2008 DPIRD has increased its surveillance effort to include areas outside of the known infested areas, in an attempt to properly delimit the true extent of skeleton weed infestations across the Western Australian cereal growing districts. The main focus of surveillance is in areas of likely spread, for example shires on the western and southern edges of the current infestation areas.

The surveillance program involves checking a minimum of three paddocks (preferably containing crop stubbles) on each selected property, such that around 300 hectares is searched per property.

The Skeleton Weed Program is also using a “spread modelling” computer program developed to identify properties with a higher risk of having skeleton weed – thus enhancing surveillance searching.

Surveillance helps landholders locate skeleton weed that they may not be aware is present on their property

Protocols checklist

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Report all suspected skeleton weed finds to DPIRD or LAG within 48 hours.

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If skeleton weed is confirmed, notify all neighbours of the discovery and location of all infestations within five working days.

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Complete a Full Search of all new infested paddocks within 14 days of confirmation.

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Complete a Full Search of all current Code 1 paddocks by 31 December.

small tick Complete a Full Search of all current Code 3 paddocks by 31 January.
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Complete a Surveillance Search of all Code 2, and all paddocks adjacent to Code 1 paddocks from last season by 31 January.

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Keep the minimum required search and treatment records and submit with property maps to your local DPIRD or LAG office by 15 February.

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Do not cultivate through marked infestations during the first seeding period after discovery of skeleton weed.

small tick Prevent active movement of skeleton weed by minimising the risk of contaminated produce and equipment moving around and off the property.

Non-compliance with protocols

By following the protocols to manage skeleton weed, landholders ensure the success of the Skeleton Weed Program. Failure to comply with any of the protocols will result in regulatory management, and this applies to both broad acre and urban landholders.

Regulatory management involves:

  • The issuing of a Direction Notice under Section 36 of the Biosecurity and Agriculture Management Regulations 2013. This Notice will require the landholder/manager to complete the nominated search/treatment work as directed and complete and submit fully compliant records to DPIRD within a specified time frame, usually seven days.
  • Failure to comply with a Direction Notice will result in the work being carried out by DPIRD under Section 38 of the Biosecurity and Agriculture Management Act 2007, with all associated costs being recovered from the landholder/manager. Prosecution will be considered where there is evidence the landholder/manager has been aware of an infestation and their responsibilities, and has made no effort to comply. 

Pest control notices

In the shires of Narembeen and Yilgarn where skeleton weed is declared category C3 (Management), DPIRD can issue a pest control notice under section 31 of the Biosecurity and Agriculture Management Act 2007. The notice will require the landholder to treat the land area, described within the notice, with herbicide to prevent seed set and will negate the need to conduct a search. It will only be issued for paddocks with widespread infestations of skeleton weed.

The landholder will not be eligible for assistance from the program.

Skeleton weed infested properties

Cropping areas

When skeleton weed is found on a property (usually in summer and autumn), it is referred to as an ‘infested property’. Each infested paddock on the property is assigned a code that signifies a particular stage in the eradication process.
A current infested paddock becomes a Code 1 paddock. Infestations are marked with a 20m buffer and must not be worked through during the next seeding period. This will allow the winter treatment application of picloram based herbicides, such as Tordon™ 75D or FallowBoss™ (or equivalent) as these are highly effective at moving through the soil profile and destroying the plant roots.
The paddock remains Code 1 until the pegged infestation(s) has received a winter treatment AND a Full Search by the landholder (or Skeleton Weed Program registered contractor) the following summer. If the paddock is found to be re-infested it remains Code 1 for the next season. If it receives a Clear Search, it progresses to Code 2. The entire paddock should then be cropped the following season (including old pegged infestation sites).
A Code 2 paddock requires a Surveillance Search post-harvest. If no plants are found it becomes Code 3. A clear Full Search the next summer results in the paddock becoming Code 4, and it is released from the ‘infested list’ of paddock/s on the property. If the paddock is re-infested at any time during this period, it returns to Code 1 and the process starts over.

Grazing areas

The codes for the pasture paddocks remain the same, and the summer searching and winter treatment regimes still apply. However, because no cropping takes place, two additional surveillance searches are required once the paddock becomes a Code 4 paddock.

This mainly applies to areas west of Gingin and Moora. As there is no cropping, fragments of plants are unlikely to be moved and re-establish, so spread is generally only by seeds.

Explanation of paddock codes



Code 1

New infested paddock/infested last search

Code 2

First clear search of previously Code 1 paddock

Code 3

Second consecutive clear search

Code 4*

Third consecutive clear search, possible release from 'infested list'

Code 5**

Surveillance Search of (non infested) suspect paddock or adjacent paddocks, no plants found

* Code 4 paddocks require a ‘paddock audit’ by DPIRD or LAG staff before release from the infested list.

** Paddocks that are not infested, but where a Surveillance Search is undertaken, are recorded as Code 5 paddocks on the Infested property paddock records.

Searching infested paddocks

  • If you have paddocks already on the infested list you will be issued with an Infested property paddock record for each infested property and paddock details indicating which paddocks require Full or Surveillance searching. Additional guidelines need to be followed:

    • Full Search of all Code 1 paddocks.
    • Surveillance Search of all paddocks adjacent to Code 1 paddocks from last season.
    • Surveillance Search of all Code 2 paddocks.
    • Full Search of Code 3 paddocks followed by a search audit is required to progress to Code 4 and release from the infested list.
    • Remember to inform your local DPIRD office post-search, to allow an audit prior to stock being introduced.
  • Code 1 paddocks should be searched as soon as possible after harvest. It is advisable to allow 5–10 days before searching harvested paddocks as this will allow skeleton weed plants to grow above the stubble; and ideally in early December, before flowering. Search all current Code 1 paddocks by 31 December.
  • Search Code 2 and 3 paddocks and paddocks adjacent to Code 1 paddocks from last search season (summer) by 31 January and record details of all searching and plant treatments on your Infested property paddock record. If paddocks adjacent to Code 1 paddocks from last season are on a neighbouring property, your neighbour(s) are responsible for searching them and also need to record their search activities.
  • Regular monitoring of all paddocks, infested sites in particular, should be ongoing.
  • All paper records, including farm maps indicating paddocks searched and the location of all infestations, must be submitted to your local DPIRD or LAG office by 15 February. Audits will be undertaken on 100 percent of all records.

The Skeleton Weed Program covers the cost of a Departmental or LAG officer to visit your property to confirm the infestation and discuss your obligations, when required

Search protocols

Full Search

Applicable to all Code 1 paddocks and Code 3 paddocks due for release from the infested list.

Full search coverage requirements varies depending on the number of people, vehicles and area to be surveilled
Full search logistics
  • Keep stubble to a maximum height of 45cm to enhance searching and limit the fire risks (particularly in heavy stubble or frosted paddocks).
  • Searching while harvesting or spraying is not a Full Search.
  • Paddocks should be livestock-free at least four weeks before searching. 
  • Allow 5–10 days before searching harvested paddocks; this will allow skeleton weed plants to grow above the stubble. Search paddocks as early as possible after this period and ideally in early to mid December – before plants begin flowering.
  • Always be prepared to find skeleton weed. Ensure all vehicles used for searching are fully equipped with flagging tape, star pickets and a post driver or drums to mark finds.
  • Take a farm/paddock map and pen with you to accurately mark finds as they are found. Search speed should range from 10 to 20km/h, depending on stubble density or pasture density.
  • Use only elevated cab, diesel-powered vehicles to reduce fire risk.
  • DPIRD recommends a minimum of a 400L firefighting unit to be present whilst searching.

Surveillance Search

For Code 2 paddocks and paddocks adjacent to:

  • Code 1 paddocks from last year
  • New find paddocks.

Full search coverage requirements vary according to area to be surveilled

If plants are found:

  • Stop and search the immediate area on foot.
  • Clearly mark all the infested area with flagging tape, drums, spears or steel posts around each plant; or clumps of plants (refer to section 1 on Marking search squares).
  • Clearly mark the infestation on the paddock map.


Marking search squares

Square sizes depend on the number of plants found in the paddock.

Dimensions of searching areas depend on the number of plants found on the paddock
Dimensions of searching areas depend on the number of plants found on the paddock


Marking a single plant find square on a paddock
Marking a single plant find square on a paddock

Single plant find

  • Mark the plant(s) using flagging tape, a star picket or a drum.
  • Search thoroughly to ensure there are no other plants, and step out a 20m buffer in all directions as shown. Where adjoining squares with single plants are within 50m of each other, combine the squares into one large square (while keeping a 20m distance between each individual plant and the edge of the square).
  • Place star pickets or drums in each corner of the square.
  • Mark the find on a farm map and submit with a Record Sheet from your Infested property paddock record to your local DPIRD or LAG office by 15 February.

Multiple plant find

  • Where the site contains multiple plants, search thoroughly to locate the extremity of the infestation and mark using flagging tape, star pickets or drums. Step out a 20m buffer from the outermost plants, as shown above.
  • Place star pickets or drums in each corner of the square.
  • Mark the find(s) on a farm map and submit a Record Sheet from your Infested property paddock record to your local DPIRD or LAG office by 15 February.

All marked squares will be GPS mapped by the Searching contractor or the local DPIRD/LAG officer.
Landholders will be provided with detailed maps showing infested squares and paddocks after the summer search

Which search method is required?


Skeleton weed searching and monitoring requirements according to paddock codes
Skeleton weed searching and monitoring requirements according to paddock codes


Infested property  paddock record

Infested property paddock record 2017-2018 (sample only)
Infested property paddock record 2017-2018 (sample only)


Landholder responsibilities

Infested properties

  • All infestations are to be treated in summer and winter according to Table 3 found in Control of Skeleton weed section. Landholder must provide a full record of searching, plus summer and winter treatments. Infested property paddock records are issued to landholders for this.
  • Paddocks with two consecutive clear searches (Code 3 paddocks) must be searched following the Full Search protocol to qualify for release from ‘infested’ status. The Full Search will be audited by DPIRD or LAG staff.
  • For pasture paddocks to qualify for release, at least two of the Clear Searches must have been done in a crop year. If no cropping occurs, two additional surveillance searches are required once the paddock becomes a Code 4 paddock.
  • All paddocks should be monitored throughout the summer and autumn, to increase the chance of detecting (and treating) plants that emerge in the weeks following the Full Search.
  • Landholders with skeleton weed infestations are eligible for assistance if a ‘Landholder Acknowledgment for Assistance’ (LAA) is signed and returned by 10 December each year.
  • Follow required search and treatment protocols once identification is confirmed by Departmental or LAG staff.

The above requirements are legal obligations under the Biosecurity and Agriculture Management Regulations 2013.

Non-infested properties

  • Ensure ability to identify skeleton weed plants at various stages of development.
  • Maintain vigilance for skeleton weed plants during normal operations and particularly at harvest time.
  • Mark the location of any suspected skeleton weed plants and report the finding to the nearest DPIRD or LAG office.
Finding skeleton weed in your property is not an indication
of any failing on your part as a farmer.
Skeleton weed is unpredictable and
can spread over long distances due to wind dispersal,
but once identified it can be managed effectively and eradicated


Annual Program changes and Control recommendation updates are described in the Skeleton weed Management Guide Section 2: Skeleton weed Control Program


Martin Atwell