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

Michael D. Day,Rachel L. Winston

doi:10.3897/neobiota.30.7113

Abstract

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.

Highlights

Introduced invasive weeds are of increasing concern and importance in the Pacific region, which is reflected by the growing number of publications and websites documenting their distribution and impacts (e.g. Swarbrick 1997, Waterhouse 1997, Meyer 2000, Shine et al 2003, PIER 2013)
The seed-feeding fly Ophiomyia lantanae, which successfully established in Hawaii, was subsequently introduced into Fiji and New Caledonia in 1911 (Guiterrez and Forno 1989), becoming the first weed biocontrol agent released in the Pacific island countries and territories (PICTs)
The number of weed biocontrol agents introduced into the 22 PICTs, their establishment status, and their current impact were extracted from Winston et al (2014) and supplemented by recent publications and personal communications with local researchers to provide an updated account through to 2015

Summary

Introduction

Introduced invasive weeds are of increasing concern and importance in the Pacific region, which is reflected by the growing number of publications and websites documenting their distribution and impacts (e.g. Swarbrick 1997, Waterhouse 1997, Meyer 2000, Shine et al 2003, PIER 2013). Introduced invasive weeds are of increasing concern and importance in the Pacific region, which is reflected by the growing number of publications and websites documenting their distribution and impacts Weeds affect ecosystem processes through impacts such as degrading soil and reducing water quality and quantity, and are second only to land clearing as a major threat to biodiversity (Meyer 2000, Sherley and Lowe 2000, Dovey et al 2004). The seed-feeding fly Ophiomyia lantanae, which successfully established in Hawaii, was subsequently introduced into Fiji and New Caledonia in 1911 (Guiterrez and Forno 1989), becoming the first weed biocontrol agent released in the PICTs

Methods

Results

Conclusion