What is classical biological control?

In only two cases did the introduction of exotic parasitoids result in successful biological control in rice production. In the first case, populations of immigrant rice leaffolder, Marasmia exigua (Butler) (Lepidoptera: Pyralidae), in the Fiji Islands were apparently reduced by the introduced larval parasitoid, Trathala flavoorbitalis (Careron) (Hymenoptera: Ichneumonidae) from Hawaii in 1928.

The second case involved the control of introduced rice striped stem borers Chilo suppressalis (Walker) (Lepidoptera: Pyralidae) in Hawaii through the introduction of an egg parasitoid – Trichogramma japonicum Ashmead (Hymenoptera: Trichogrammatidae) from Japan and two larval parasitoids – Eriborus sinicus (Holmgren)(Hymenoptera: Eulophidae) and Bracon chinensis Szepligeti (Hymenoptera: Braconidae) from China in 1929. All three parasitoids established and helped to reduce infestation of this stem borer.

Several attempts have been made to introduce exotic parasitoids to control indigenous rice insect pests in South and Southeast Asia but none was successful. One such example involved the introduction of a larval parasitoid Paratheresia claripalpis (ven der Wulp) (Diptera: Tachinidae) from Trindad to Malaysia to control the dark-headed stem borer Chilo polychrysus (Meyrick) in 1951. A more recent example involved the introduction of two egg parasitoids Psix lacunatus (Johnson and Masner) (Hymenoptera: Scelionidae) and Telenomus cyrus (Nixon) (Hymenoptera: Scelionidae) to Palawan Island from the Island of Luzon, Philippines during 1985-87 to control Malayan black bug, Scotinophara coarctata (F.) (Hemiptera: Pentatomitidae). This project was not successful.