Biological control of weeds has been conducted since 1902, resulting in over 500 biological control agents being internationally released against nearly 200 weed species in over 90 countries.

A persistent problem in weed biocontrol is how to reliably predict whether a plant that supports development in laboratory host-specificity testing will be utilized in field conditions, and this is undoubtedly preventing releases of safe and effective agents.

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.

The introduction and naturalization of plant species outside their native range is likely to intensify with continuing globalization and increasing international trade. Although only a very small percentage of naturalized plant species become invasive the ones that do can have severe negative effects of individual vital parameters of native species, species richness and diversity agriculture and forest production, nutrient and fire cycles water availability and recreation and tourism.