Biological control of weeds in the 22 Pacific island countries and territories: current status and future prospects

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Biological control of weeds in the 22 Pacific island countries and territories: current status and future prospects

Biological control of introduced weeds in the 22 Pacific island countries and territories (PICTs) began in
1911, with the lantana seed-feeding fly introduced into Fiji and New Caledonia from Hawaii. To date, a total
of 62 agents have been deliberately introduced into the PICTs to control 21 weed species in 17 countries.
A further two agents have spread naturally into the region. The general impact of the 36 biocontrol agents
now established in the PICTs ranges from none to complete control of their target weed(s). Fiji has been
most active in weed biocontrol, releasing 30 agents against 11 weed species. Papua New Guinea, Guam,
and the Federated States of Micronesia have also been very active in weed biocontrol. For some weeds such
as Lantana camara, agents have been released widely, and can now be found in 15 of the 21 PICTs in which
the weed occurs. However, agents for other commonly found weeds, such as Sida acuta, have been released
in only a few countries in which the weed is present. There are many safe and effective biocontrol agents
already in the Pacific that could be utilised more widely, and highly effective agents that have been released
elsewhere in the world that could be introduced following some additional host specificity testing. This paper
discusses the current status of biological control efforts against introduced weeds in the 22 PICTs and reviews
options that could be considered by countries wishing to initiate weed biological control programmes.