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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.

The Fourth Assessment Report of the IPCC (IPCC AR4) Working Group II (2007) identifies small island states as being among the most vulnerable countries of the world to the adverse impacts of climate change. Hay, el al.y (2003) in discussing the Pacific's observed climate noted that compared to earlier historical records during the twentieth century, the southern Pacific had experienced a significantly drier and warmer climate (by 15 percent and 0.8°C, respectively). The Central Equatorial Pacific is facing more intensive rain (about 30 percent) and a similarly hotter climate (0.6°C), and sea surface temperatures in both areas have increased by about 0.4°C. These conditions are linked to an increased frequency of El Nino episodes since the 1970s (without alternating La Nina events). Other studies show that climate projections for the South Pacific indicate warming of 0.8 to 1.8°C and precipitation changes that range from -8 to +7 percent by mid-century (Ruosteenoja, el ai, 2003). By the end of the century, projected warming is 1.0 to 3.1°C and precipitation changes range from -14 to +14 percent. Projections of globally averaged sea-level rise range from 0.18 m to 0.58 m in 2090-2099 relative to 1980-1999; while tropical cyclones are likely to become more intense, have higher peak wind speeds, and bring heavier rainfall (IPCC, 2007). Thus, it is clear that there are winners and losers when it comes to climate and food security with mostly the countries in the mid to higher latitudes benefiting from global warming and the small island countries of the Pacific in the warmer latitudes standing to lose the most. The IPCC has concluded that the mounting evidence shows that climate change is unequivocally happening and may worsen in future; there is a need to act urgently to minimize these impacts.