(37(2):211-219)Biological Control of Coconut Leaf Beetle in Taiwan

臺灣省農業試驗所於民國72年自關島引進紅胸葉蟲釉小蜂（Tetrastichus brontispae）供可可椰子紅胸葉蟲（Brontispa longissima）之防治。自民國73年l月起至75年6月止先後分別在高雄縣澄清湖、大樹、湖內，屏東縣林邊、里港，臺束縣知本、建和、東河、成功，花蓮縣豐濱、吉安、鳳林，雲林縣斗南，嘉義縣大埔以及臺北市植物園等處遭受紅胸葉蟲為害之椰樹上釋放釉小蜂共l06次，共計143,082隻成蜂，各地區之釋放次數為l至14次，寄生率可達90％以上。該蜂釋放後都能在各該地立足，且能自行分散至鄰近椰子產區，其中澄清湖、大樹、林邊以及知本等地均已獲得明顯之防治成效。釉小蜂可寄生於紅胸葉蟲之老熟幼蟲及蛹齡l－6天之蛹，而以1－4天之蛹較為所好。該蜂在25°C，70～80％RH時完成一世代需19～21天，成蟲飼以純蜜壽命為雌蟲2～20天，平均14.l 天；雄蟲2～18天，平均為11.6天；卵期為3天，幼蟲期有三齡，約需6天。前蛹期l天，蛹期9～11 天。每隻被寄生之寄主蛹可羽化出釉小蜂3～48隻，平均20隻。雌雄蜂性比平均為3.5 : 10。 The coconut leaf beetle, Brontispa longissima Gestro (Chrysomelidae, Coleoptera), is a serious pest of the coconut palm in Taiwan. The larval and pupal parasitoid, Tetrastichus brontispae (Ferr.) (Eulophidae, Hymenoptera), was introduced into Taiwan from Guam in November, 1983. A total of 106 releases of about 143,082 adults were released to Kaohsiung, Pingtung, Taitung, Hualien, Taitung, Chiayi, Yunlin and Taipei from January, 1984 through June, 1986. It is evidently that the introduced parasitoid has already established in Taiwan and hence to perform as a good biological control agent of the coconut leaf beetle. T. brontispae can parasitize the mature larvae and pupae of B. longissima, however apparently preferred to oviposite in 1 to 4 days old pupae. Under the room temperature of 21°C and 70─80% RH, the parasitoid required 19 to 21 days to complete its life cycle from egg to adult. The duration of egg, larval, prepupal and pupal stages were approximately 3, 6, 1, and 9 to 11 days, respectively. The longevity of adult male and female averaged 11.6 and 14.1 days, respectively. Generally, an average of 20 parasitoids were emerged from one host pupa, the sex ratio was 3.5 (female) : 1 (male)