In 1996 Paterson's Curse was listed in the Restoration Plan as "very abundant and widespread". It was particularly dense in the western part of the park, despite annual spraying. There were smaller patches in the back paddock.
Parks Victoria no longer sprays weeds to any significant extent, and by 2016 Paterson's Curse had increased in density in many areas such as the former back paddock. There are also dense areas near Mickleham Road and on Melbourne Airport land. More recently it has become common in Twin Dams Paddock, spreading from a large infestation in the adjoining Greenvale Reserve. The council sprayed the reserve in 2020, but the damage is done and they will not be able to control it due to seed spreading back from Twin Dams. Also in 2020 many isolated plants were found on Greenvale Sanatorium Land for the first time. They are probably spreading both from Twin Dams Paddock and also the privately owned former sanatorium site, where infestation has also increased significantly in recent years. Note however that weed populations fluctuate greatly from year to year depending on the weather.
Biological Control
Common Name | Scientific Name | Released | Effectiveness Nationally |
---|---|---|---|
Paterson's Curse Crown Weevil | Mogulones larvatus | 1993 | killed up to 80% of plants prior to flowering in NSW trial over 8 years |
Paterson's Curse Root Boring Weevil | Mogulones geographicus | 1996 | unknown |
Paterson's Curse Taproot Flea Beetle | Longitarsus echii | 1996 | most damaging agent in drier areas |
Paterson's Curse Leaf-mining Moth | Dialectica scalariella | 1998 | ineffective |
Paterson's Curse Pollen Beetle | Meligethes planiusculus | 1998 | ineffective |
Paterson's Curse Stem Beetle | Phytoecia coerulescens | 1998 | ineffective |
The Paterson's Curse Crown Weevil was released at Melbourne Airport in the mid 1990s and is present in the park. In Nov. 2016 grubs, presumably of the Taproot Flea Beetle, were also found in the roots of one plant. Paterson's Curse is considered to be a major biological control success story in parts of the country but not at Woodlands Historic Park. Even in years when many plants were obviously affected by the Crown Weevil, I do not recall seeing any plants that were prevented from flowering. The continued increase of this weed in the park is probably due to the chronic over-grazing by Kangaroos. There are now no Kangaroos in the Back Paddock, and Patterson's Curse has become less noticeable there as the grass has recovered. The amount of Patterson's Curse seed in the soil may decrease over time, although autumn burns in Kangaroo Grass areas would probably benefit the weed and could lead to mass flowering which would reverse the gains.