花蓮地區台灣三月始灰象鼻蟲密度調查與防治

Survey and control of Sympiezomias cribricollis in Hualien area

"近兩年來，花蓮地區許多栽培文旦的農民反應象鼻蟲數量增高，文旦受害嚴重，本蟲經鑑定結果，中名為台灣三月始灰象鼻蟲，學名為Sympiezomias cribricollis Kono。經調查，台灣三月始灰象鼻蟲已廣泛存在於瑞穗鄉文旦園中，不只取食文旦葉片造成缺刻，亦棲息於枝幹、花器與幼果上，本象鼻蟲在柑桔類上曾發現過，約於3月出現，主要食害嫩葉、嫩梢，有群集和假死習性。針對花蓮縣瑞穗鄉鶴岡地區7處文旦果園進行衛星定位與本象鼻蟲密度調查，平均每株文旦上的象鼻蟲數為0至32.3隻，在文旦園調查每平方公尺雜草上的象鼻蟲數為0至11.3隻，發現象鼻蟲的分佈極不平均。另外，調查台灣三月始灰象鼻蟲於花蓮地區所危害的植物種類，發現本蟲至少可取食7科11種以上的植物，且本蟲族群已有往文旦園外遷移的現象。測試7種推薦用於柑桔類的殺蟲劑對本蟲的致死效果，藥劑經處理文旦葉片與象鼻蟲後，結果顯示以畢芬寧、丁基加保扶與加保扶1,000倍稀釋液對本蟲的致死率極高。藥劑處理文旦葉片方面，結果顯示以畢芬寧的效果最好，與同時處理文旦葉與蟲體的效果一樣，3天後均可達100%的致死率，加保扶的效果次之，3天後達93%的致死率，7天可達100%的致死率。另一方面，噴施丁基加保扶、畢芬寧1,000倍稀釋液與賽洛寧4,000倍稀釋液於田間進行防治試驗，藥劑處理2至3次後調查文旦植株上的象鼻蟲密度，結果顯示3種藥劑均能防治本蟲，其防治率為37.9至77.2%。另以菸草浸液等6種非農藥防治資材測試對台灣三月始灰象鼻的致死效果，結果顯示，處理兩株白殭菌10天後分別可達86與100%的致死率，其餘資材的致死率低，與對照組（展著劑）差異不顯著。"

"Recently, the wentan pomelo farmers reported the rapid rise of the weevil population and the decrease in the pomelo productivity in Hualien area. These weevils were identified as Sympiezomias cribricollis Kono. We also found that the weevils spread widely in Rueisuei. The weevils not only fed on leaves to cause damages but also stayed on fruit to endanger its growth. According to the density investigation of the weevils in seven pomelo orchards located by Global Positioning System(GPS) in Hegang area of Hualian County, we detected 0-32.3 individuals on one pomelo plant and 0-11.3 individuals on weeds in a square meter, indicating the uneven distribution of weevils in the field. When polmelo leaves and adult meevils were dipped in one of the seven pesticide suspensions before being placed on a petri dish, bifenthrin, carbosulfan and carbofuran were found to be effective in increasing the mortality rate. High mortality rate was obtained even when non-treated adult weevils were placed on pomelo leaves treated with bifenthrin or carbofuran. When pomelo trees and weeds in the field were sprayed with bifenthrin, carbofuran or lamda-cyholothrin, all the pesticides tested were effective in reducing the weevil population, with the control rate ranging from 37.9 to 77.2 %. For increasing the control rate, farmers should cut weeds before chemical spray to increase the contact of chemical with weevils. Among six non-chemical control materials tested, only two strains of Beauveria bassiana were effective, causing 86 to 100 % weevil mortality."