| Summary: | 碩士 === 臺灣大學 === 昆蟲學研究所 === 98 === 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.
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