The methanol extracts and essential oils from 9 medicinal plants, Ulmus davidiana var. japonica, Cryptomeria japonica, Hedera rhombea, Prunus mume, Taxus cuspidatal, Paulownia coreana, Kalopanax pictus, Paris verticillata, and Ixeris dentata were tested for their insecticidal activity against larvae of P. xylostella by topical application method. And the methanol extracts and essential oils obtained from Paris verticillata and Ixeris dentata were subjected to a screening test for their antifeeding activities, pupation and adult emergence of P. xylostella by a leaf-dipping method at a concentration of LC50 value. The methanol extract from all parts of P. verticillata and the essential oil from all parts of I. dentata exhibited potent activity with LC50 of 6.34 and 6.53(g/L) 5days after treatment. And the essential oil from all parts of P. verticillata and I. dentata have shown strong antifeeding activity compared to those of methanol extracts against larvae of P. xylostella. Also, the methanol extract and essential oil of P. verticillata and I. dentata gained 37.5%, 5.0% of pupation and 22.5%, 2.5% of adult emergence, respectively.

The methanol extracts and essential oils from 9 medicinal plants, Ulmus davidiana var. japonica, Cryptomeria japonica, Hedera rhombea, Prunus mume, Taxus cuspidatal, Paulownia coreana, Kalopanax pictus, Paris verticillata, and Ixeris dentata were tested for their insecticidal activity against larvae of S. exigua by topical application method. And the methanol extracts and essential oils obtained from Paris verticillata and Ixeris dentata were subjected to a screening test for their antifeeding activities and pupation and adult emergence of S. exigua by a leaf-dipping method at a concentration of LC50 value. The methanol extract from the bark of C. japonica, the leaf of H. rhombea and all parts of P. verticillata exhibited potent activity with LC50 of 5.02, 4.21 and 5.46(g/L) 5days after treatment, respectively. But all of the essential oils except for I. dentata with LC50 of 4.92(g/L) had shown high potential insecticidal activity compared to the methanol extracts against S. exigua. And the essential oil from all parts of P. verticillata and I. dentata have shown stronger antifeeding activity than those of methanol extracts against larvae of S. exigua. Also, the methanol extract and essential oil of P. verticillata and I. dentata affected growth pattern showing those of 32.5%, 10.0% of pupation and 27.5%, 10.0% of adult emergence of S. exigua.