Report to the Republic of Palau: 2008 update on Invasive Plant ...

• Pennisetum setaceum (fountain grass) was present at only a few locations in 2002 and was
not observed in this survey. While <strong>the</strong> specimens noted previously were planted as
ornamentals, if this species escaped in<strong>to</strong> wildlands it would contribute <strong>to</strong> <strong>the</strong> risk and
intensity <strong>of</strong> wildfires (it has wind-dispersed seed). A good precautionary measure would be
<strong>to</strong> eliminate any examples found and prohibit fur<strong>the</strong>r importation (it is commonly used in
landscaping).
• The single specimen <strong>of</strong> Pereskia aculeata (Barbados gooseberry, leafy cactus) on Ngercheu
(Carp) Island should be eliminated before it spreads.
• Pistia stratiotes (duckweed, water lettuce) was seen in cultivation at a house in Airai. The
source is unknown. The extent <strong>of</strong> this species in <strong>Palau</strong> should be immediately determined
and, if feasible, it should be eradicated. Unless it is already widespread, import and sale <strong>of</strong>
this species should be prohibited as it poses a grave danger <strong>to</strong> <strong>Palau</strong>’s rivers and reservoirs.
• Pi<strong>the</strong>cellobium dulce (kamatsíri, opiuma, Madras thorn), was seen only in cultivation in Airai
although o<strong>the</strong>r cultivated specimens may exist. Since this species appears <strong>to</strong> be present only
<strong>to</strong> a limited extent it should be a candidate for eradication.
• Both Pluchea carolinensis (sour bush) and P. indica (Indian fleabane) have apparently been
on Angaur and Peleliu for a long time without becoming a serious problem. However, since
Pluchea carolinensis has a bad reputation as an invasive species elsewhere and is not
widespread, it could possibly be eliminated at low cost, but this would not be high priority. It
is a serious pest on some o<strong>the</strong>r Pacific islands and eradication would prevent its possible
movement <strong>to</strong> o<strong>the</strong>r <strong>Palau</strong>an islands where conditions might prove more suitable for its
spread.
• The principal infestation <strong>of</strong> Solanum <strong>to</strong>rvum (prickly solanum, devil’s fig) seems <strong>to</strong> be in <strong>the</strong>
Nekken area <strong>of</strong> Babeldaob. It should be surveyed and mapped for extent and evaluated for
control measures (eradication if feasible). Individual plants in wildland areas should be
eliminated whenever <strong>the</strong>y are found. Since this species is most likely <strong>to</strong> occur in farm fields
and grazed areas, landowners should be encouraged and provided advice and assistance <strong>to</strong>
remove plants on <strong>the</strong>ir land. A biological control agent, Leptinotarsa undecimlineata, is
reportedly available, but may not be appropriate as <strong>the</strong> infestation appears <strong>to</strong> be scattered.
• There is only one known remaining infestation consisting <strong>of</strong> several trees <strong>of</strong> Spathodea
campanulata, <strong>the</strong> o<strong>the</strong>rs having been eliminated in an eradication program. Hopefully this
last infestation can be removed in <strong>the</strong> near future.
• Sphagneticola [=Wedelia] trilobata (ngesil ra ngebard, Singapore daisy) is planted as an
ornamental and it can be a problem along roadsides, in gardens and fields, or any o<strong>the</strong>r open,
disturbed areas. Fur<strong>the</strong>r planting should be discouraged and advice should be made available
<strong>to</strong> landowners and <strong>the</strong> public on how <strong>to</strong> control it outside <strong>of</strong> cultivation.
• Tecoma stans (yellow bells, yellow-elder, yellow trumpetbush) is quite common, mostly in
cultivation. It should be moni<strong>to</strong>red for spread as it has wind-dispersed seed and is a problem
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