How To Manage It?
Best practice management
The economic costs of control are high once Parkinsonia becomes established. The prevention of spread within and between catchments, early detection and control of small manageable outbreaks are thus high priorities when considering management strategies (CRC 2003).
Soil or sand which could contain Parkinsonia seeds should not be removed from infested areas. Any transport or machinery used in infested areas should be thoroughly cleaned before moving to other areas. Because water is responsible for much of the spread of Parkinsonia, outbreaks on watercourses, particularly in upper catchments, are a priority for control (CRC 2003).
Research into Parkinsonia control commenced in the 1950s and has been ongoing. The results from this research have shown that seedlings are particularly susceptible to different forms of control, especially fire, drought or inundation, soon after germination. An integrated approach using several weed management techniques (e.g. mechanical and chemical control, fire) is the most effective way to deal with dense infestations of Parkinsonia. However, the characteristics of the infestation (e.g. size, density, location, position within the catchment) and the availability of resources will determine the exact course that control should take.
Chemical control: There is a wide range of herbicides registered for Parkinsonia control, with several different application methods. Herbicides are useful for controlling dense high priority infestations but otherwise may be too expensive for widespread use. Particular care with herbicides should be taken near waterways (CRC 2003). Herbicides can be applied in a number of ways including aerial spraying and manual foliar application. Basal bark spraying and cut stump application can also be effective. For general information of the use of chemicals please visit the Australian Pesticides and Veterinary Medicines Authority at http://www.apvma.gov.au
Non-chemical control: Mechanical removal, such as hand pulling for small plants and bulldozing or chain pulling for larger plants, can be effective as long as roots are removed to a depth of 200 mm to prevent regrowth. Mechanical removal is more cost-effective that chemical control over large areas. However, it is not advised for river banks due to the potential for erosion and damage to non-target species. Follow-up is essential to treat seedlings (which can germinate prolifically in the disturbed ground) and any remaining adult plants (CRC 2003).
Fire kills seedlings and seeds on the surface and is an excellent form of follow-up control after mechanical or chemical control. With mature plants, however, the results are mixed. The Queensland Department of Natural Resources and Mines is currently researching which fire regimes give maximum kill rates of mature Parkinsonia in central Queensland (CRC 2003).
Biological control: Parkinsonia has also been recognised as a target for biological control through a cross-jurisdictional government process. This allows activities to be undertaken to develop effective biological controls. Biological control has yet to show any major successes but research is continuing (CRC 2003).
For more detailed information on control strategies see Deveze (2004).
For further information see the Parkinsonia Best Practice Manual (available at https://www.weeds.org.au/WoNS/Parkinsonia)
Does it have a biological control agent?
YES. Five biocontrol agents released: including seed-feeding beetles (Penthobruchus germaini and Mimosetes ulkei), a leaf bug (Rhinacloa callicrates) and leaf-feeding moths Eueupithecia cisplatensis, Eueupithecia vollonoides) (Harvey, et al 2023).
When does it grow? (lifecycle/growth calendar)
Parkinsonia plants grow quickly and are known to flower as early as the summer of their second year.
Established plants may bear flower and fruit at anytime of the year but, across Australia, flowering is generally in the warmer months after winter (from as early as July to the end of January) with pods developing soon after (October to April). Seeds germinate in response to prolonged periods (several days worth) of rain, with most germination occurring (CRC 2003).