東方果實蠅之防治現況與展望

Abstract

東方果實蠅為日據時代以來，台灣果樹的重要害蟲。其防治試驗及工作，在台灣已有70多年的歷史。其間經過數次的嘗試錯誤，已確定利用甲基丁香油誘殺板之滅雄法為最佳防治方法。於是自去年(1994)7月下旬，將防治方法全面改為利用誘殺板之滅雄法。即使用以98％甲基丁香油中添加混合比成5％之乃力松及抗氧化劑，將如上10ml之藥液滴於4.5×4.5×0.9cm3纖維板上浸漬一夜者。目前暫以10萬公頃之栽植果樹地區為主，每兩個月分發一次誘殺板，以每公頃6枚的比例，讓農民自行懸掛。另在宜蘭縣員山鄉等全省六十個地區，選擇栽培中之果園、廢棄果園及空地等各懸掛3個偵測用誘殺器，共540個，進行誘殺雄性蟲數之調查。此時將2ml之含毒甲基丁香油沾於棉花後裝於誘殺器中，在誘殺器下方接上尼龍紗製作網口直徑35cm、深40cm的漏斗型接網以便收集誘殺蟲。將它懸於上述果園、廢棄果園及空地距離地面約1.5m之處。至1994年11月23日為止，就540個誘蟲器而言，一個誘蟲器一天平均誘蟲數，已自開始防治時之77.7隻降低為12.6隻，即已減少至約l/6，效果相當顯著。然在部份地區之誘殺蟲數仍居高不下，經初步分析結果推測，其最大原因為處理面積不足，使未處理地區之果實蠅源源不斷的入侵處理地區。本文除對其原因深入探討外，並就將來應採取之對策加以討論。 Oriental fruit fly (Dacus dorsalis)is one of the most destructive pests on many kinds of fruit in Taiwan. The damage by this fly is recorded from Japanses ocupied period and more than 70 year had passed since the control operation in this island. Through some error and trial of the control methods, male annihilation is already proved most effective and promising method against this fly. Then, the large scale male annihilation is started since end of July 1994 with poisoned methyl eugenol (ME) soaked fiber board. Accordingly 4.5x4.5x0.9cm fiber board are dipped in a mixture of 98% ME, 5% Naled and anti-oxidant for night. Then, lOmI of mixture are considered to be soaked into a piece of the board. In the present, 100,000ha of fruit orchard are decided for the treated area, where the ME soaked fiber boards applid in the dosage of 6 piece/ha every 2 months. The application is done by the farmer themselves. Besides, 60 localities covered whole the island are designated as the oriental fruit fly monitoring site. In those area, 9 monitor traps are set at orchard, with fruit plants, abandoned orchard and not cultivating area. Namely 540 monitor traps are used to investigate the change attracted male fly for 60 localities. In the monitor trap, cotton soaked 2m1 of poisoned ME is set. The trap is hung on a branch at the 1.5m height with 35cm Diameter and 40 cm length nylon net to accomodate the attracted male flies. No. of attracted is counted every 10 days. At the begining of moni-toring, namely on 23 July 1994. 77.7 male /trap/ day were attracted in an average of provided 540 traps. While , through 3 month¡¦s survey, No. of attracted male decreased apparently. Accordingly, on 23 Nov., No. of attracted in average recorded 12.6, namely around 1/6 of the first survey. However, in some area, the density of the flies still keep in high level. Through preliminary analysis, it may almost due to the limited treated area and immigration of the flies from the untreated area. In this paper, the cause of the low efficiency in some localities, and the future prospective aspect are also discussed.