Biological Control of the Invasive Plant Chromolaena odorata (Asteraceae). R. Muniappan and G.V.P. Reddy. Agricultural Experiment Station, University of Guam, Mangilao, Guam

Chromolaena odorata (Asteraceae) is of Neotropical origin, introduced as an ornamental plant to the Calcutta Botanical Gardens, India in 1836. It escaped cultivation and eventually became an invasive weed throughout the humid tropical Asia. It was introduced in West Africa in 1946 and to Micronesia in the 1960s. A different biotype of C. odorata has established in South Africa. This plant is highly allelopathic. It occupies vacant lands, pastures, disturbed forests, game reserves, roadsides, and orchards. In the dry season, the tops dry up and become a fire hazard. For biological control of this weed several natural enemies were screened and of these the arctiid moth, Pareuchaetes pseudoinsulata and the tephritid gallfly, Cecidochares connexa have proven effective. P. pseudoinsulata has been established in Ghana, India, Indonesia, Philippines, Guam, Saipan, Rota, Tinian, Pohnpei, Chuuk, Kosrae, Yap and Papua New Guinea. C. connexa has been established in Indonesia, Guam, Rota, Chuuk, Yap, Pohnpei, Kosrae and Papua New Guinea. To coordinate the biological control of this weed on an international level, a working Group of the International Organization of Biological Control has been formed. Under its auspices, six international workshops were conducted. Six proceedings and sixteen newsletters were published. A seventh International workshop has been scheduled to take place in Taiwan in 2006.