Biological control activities in the Mariana Islands Pacific Ocean from 1911 to 1988

Biological control started in the Marianas in 1911. Biocontrol agents have been introduced to control herbivorous insects, weeds, dung, molluscs, livestock pests, mosquitoes and household pests. In all, 104 species of insects, two predatory mites, three snails, one nematode and four vertebrates have been intentionally introduced to Guam for the purposes of controlling 41 pest species. Of the insect species, 34 established, 48 did not establish, 5 established temporarily and the status of the rest is not known. Additional introductions were made to other islands in the Marianas. Among the pests most successfully controlled by biological agents were Achatina fulica, Aleurocanthus spiniferus, Aleurothrixus floccosus, Aspidiotus destructor, Brontispa mariana, B. palauensis, Epilachna vigintisexpunctata philippinensis, Nipaecoccus viridis, Erionota thrax, Penicillaria jocosatrix, and Spodoptera litura. Two weeds, Lantana camara and Chromolaena odorata have been successfully controlled by herbivorous insects. Most attempts at biological control in the Marianas have been transfers of species successfully introduced elsewhere. Most species introduced from temperate climatic zones failed to establish. Species which established on Hawaii [USA] frequently established on Guam as well. Reasons for failure to establish were varied. Against Homopteran pests, 58% of the introduced natural enemies established. The establishment rate against Lepidoptera and Diptera was low.