Ekstrak tanaman dapat mempengaruhi fisiologi dan biokimia serangga yang meliputi penghambatan makan, asimilasi makanan, dan dan aktivitas enzim detoksifikasi, yaitu sitokrom b5 dan sitokrom P450. Penelitian ini bertujuan untuk menguji pengaruh ekstrak campuran Tephrosia vogelii : Piper aduncum (1 : 5) terhadap fisiologi Crocidolomia pavonana (F.) dan pengaruh ekstrak P. aduncum terhadap biokimia C. pavonana. Pengujian ekstrak campuran T. vogelii : P. aduncum (1 : 5) pada konsentrasi 0,06% atau setara dengan LC 95 menghambat makan larva C. pavonana hingga 94,82%. Ekstrak campuran yang diuji pada LC 25 (0,007%) dan LC 50 (0,014%) menyebabkan gangguan pertumbuhan relatif larva C. pavonana. Gangguan ini disebabkan oleh toksisitas intrinsik ekstrak campuran yang masuk ke dalam tubuh serangga. Selain gangguan pada pertumbuhan larva uji, juga terjadi peningkatan daya cerna serangga sebesar 11,11% sebagai bentuk adaptasi terhadap senyawa toksik tumbuhan. Adaptasi lain yang dilakukan larva C. pavonana adalah mekanisme detoksifikasi terhadap ekstrak P. aduncum. Hal ini tampak dari peningkatan aktivitas enzim oksidasi sitokrom b5 dan sitokrom P450 pada perlakuan in vivo dan in vitro jika dibandingkan dengan kontrol. Penelitian ini memberikan informasi mengenai cara kerja ekstrak campuran T. vogelii : P. aduncum (1 : 5) pada larva C. pavonana dan mekanisme detoksifikasi larva terhadap ekstrak P. aduncum. Key words: antifeedant, asimilasi, enzim, oksidasi, sitokrom ABSTRAKPlant extracts have been known to cause physiological and biochemical interferences against insect, such as feeding inhibitor, food assimilation, and changes on activity of cytochrome b5 and cytochrome P450. This study was carried out to examine the effect of the extracts mixture of Tephrosia vogeliiand : Piper aduncum (1 : 5) on the physiology of Crocidolomia pavonana (F.) as well as extract of P. aduncum on biochemical of C. pavonana. The study showed that larvae of C. pavonana was experiencing a feeding inhibition until 94.82% after treated with extracts mixture on concentration 0.06% or equivalent to LC 95 . However, larvae treated with extracts mixture on LC 25

The research was conducted at Laboratory of Insect Physiology and Toxicology of Plant Protection Department of Bogor Agricultural University from May to July 2008. Leaves, twigs, barks, and roots of Eurycoma longifolia (Pasak bumi) were extracted with hexane, ethyl acetate, and methanol solvens. The extraction was used single method and level method. Insecticidal activity of each extract has been examined in laboratory to major cabbage pests Crocidolomia pavonana using leaf residual method. Methanol root extract from single method and level method caused 100 and 75.5% mortality of insect test respectively. Hexane and ethyl acetate extracts of leaves, twigs, and barks have low insecticidal activity. The antifeedant effect worked at insect test and varied depends on concentration level. Antifeedant effect also contributed to mortality of larvae along with toxicity of each extract.