Controls were acetone with 1%
tween-80, the solvent used to prepare test solutions. Leaves
of Chinese kale (2 cm) were dipped in different concen trations
of the extracts separately for 1 min and air-dried. Thirty 3 rd
instar larvae of P.xylostella each were released in plastic
cups (10 ml capacity) containing either treated or untreated
(control) leaf disks as one replicate