台灣藜對三種植食性害蟲之忌避效果

Abstract

台灣藜 (Chenopodium formosanum) 為台灣南部原住民傳統作物，本研究探討台灣藜粗萃液對溫室蔬菜和花卉害蟲：小菜蛾 (Plutalla xylostella)、桃蚜 (Myzus persicae) 及銀葉粉蝨 (Bemisia tabaci) 之忌避活性。將種子、種皮、葉片的甲醇粗萃液針對三種害蟲進行選擇及非選擇性之忌食與忌產卵試驗。結果顯示，台灣藜的葉子與種皮之粗萃液對小菜蛾幼蟲、桃蚜若蟲及銀葉粉蝨成蟲具忌食活性；對小菜蛾成蟲和銀葉粉蝨成蟲，亦具忌產卵活性。忌食結果顯示葉子的粗萃液於 1% 濃度時，桃蚜和銀葉粉蝨的選擇性忌食率平均為 32.43% 及 37.95%，而非選擇性忌食率平均為 30.13% 及26.55%，對小菜蛾幼蟲選擇性忌避食率平均為 29.73% 而非選擇性忌食率平均為 21.40%；忌產卵選擇性結果顯示，對小菜蛾及銀葉粉蝨平均為 39.31% 和 42.83% 之忌產卵率，而非選擇性試驗則分別為 29.33% 及 32.3% 之忌產卵率；根據試驗結果，葉子粗萃液的忌避活性高於種皮粗萃液，而種子粗萃液則較微弱。進一步將葉子粗萃物進行液-液分離，得到乙酸乙酯層、正丁醇層及水層。忌食結果顯示，1% 水層粗萃液對三種害蟲 (桃蚜、銀葉粉蝨、小菜蛾) 的選擇性忌食率分別平均為21.88%、30.73%、27.53%，非選擇性忌食率平均為 24.33%、23.75%、28.27% 皆高於另兩層萃取物；選擇性忌產卵結果顯示，小菜蛾及銀葉粉蝨的忌產卵率分別平均為 33.89%、35.16%，而非選擇性結果分別平均為 31.26% 及 37.90%。另外，氣相層析質譜儀分析鑑定結果中，在忌避效果最佳的葉子粗萃液發現 15 個化合物，種皮發現 18 個化合物，種子 7 個化合物，再經液-液分離後，由水層鑑定出 16 個化合物，正丁醇層 14 個化合物，乙酸乙酯層 8 個化合物。

Djulis (Chenopodium formosanum) is the traditional crops in the southern Taiwan. This study aims to investigate the deterrent effect of crude extract from leaves and seeds of djulis to the Plutalla xylostella, Myzus persicae and Bemisia tabaci which are the common agricultural pests in vegetables and flowers in greenhouse. We evaluated the methanol extract of djulis for their anti-feeding and anti-oviposition efficiency by using choice and no-choice bioassay. The results showed that the deterrent efficiency of 1% leaf crude extract for M. persicae and B. tabaci on anti-feeding were 32.43% and 37.95% in choice test；in no-choice test, the deterrent efficiency were 30.13% and 26.55%. The efficiency of anti-feeding on P. xylostella in choice test and no-choice test were 29.73% and 21.40%. For anti-oviposition, the efficiency of leaf extract in choice test were 39.31% and 42.83% on P. xylostella and B. tabaci, however, the efficiency in no-choice test were 29.33% and 32.3%. Overall, the deterrent of methanol leaf extract of djulis for pests was better than testa and seed extract. The methanol leaf extract were further partitioned into ethyl acetate, butanol and water layer. The results showed that anti-feeding efficiency of 1% water layer for M. persicae, B. tabaci and P. xylostella were 21.88%, 30.73% and 27.53% in choice test. However, the deterrent efficiency were 24.33%, 23.75% and 28.27% in no-choice test. The results of choice and no-choice bioassay for water layer were better than butanol layer and ethyl acetate layer. In addition, the efficiency of anti-oviposition for P. xylostella and B. tabaci were both higher than 33% in choice test, however, the efficiency in no-choice test were 31.26% and 37.90%. The gas chromatograms of leaf extract showed the difference from seed and testa extract. Moreover, fifteen components were identified from leaf extract, eighteen components were identified from testa extract and seven components were identified from seed extract by gas chromatography-mass spectrometry (GC/MS). Similarly, the gas chromatograms of water layer showed the difference from butanol layer and ethyl acetate layer. Moreover, sixteen components were identified from water layer, fourteen components were identified from butanol layer and eight components were identified from ethyl acetate by GC/MS. In conclusion, leaf crude extract of djulis have efficiency of both anti-feeding and anti-oviposition on P. xylostella, M. persicae and B. tabaci, indicating the potential candidacy of the djulis as a new deterrent plant to agricultural pests.