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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 form Hawaii. To date, a total of 62 agents have been deliberately introduced into the PICTs to control 21 weed species in 17 countries.

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.

Biological control of weeds in Vanuatu began in 1935, with the introduction of the tinged Teleonemia scrupulosa to control Lantana camara. To date, nine biological control agents have been intentionally introduced to control eight weed species. Seven of these agents have established on their respective hosts while an eighth, Zygogramma bicolorata, an agent for Parthenium hysterophorus has only recently been released and establishment is unlikely.

PACC reports

Reports from the PACC project

n More than 60 percent of the world’s reefs are under immediate and direct threat from local sources—such as overfishing, destructive fishing, coastal development, watershed-based pollution, or marine-based pollution and damage (see map inside front cover). n Approximately 75 percent of the world’s coral reefs are rated as threatened when local threats are combined with thermal stress. This reflects the recent impacts of rising ocean temperatures, linked to the widespread weakening and mortality of corals due to mass coral bleaching (figure ES-1, column 6).