Plant species
Seedlings of oilseed rape (Brassica napus L, variety: Favorite) in the 5th leaf stage were used as a host plant for P. xylostella larvae during bioassays. To produce the required seedlings, seeds of the same variety were sown in a tray containing sterilized mixture of peat-moss and sand (1:1 proportion) as a growing medium then germinated seedlings were transplanted into black plastic pots (10 cm diameter and 15 cm depth) containing the same growing medium. The potted plants were properly irrigated and optimally fertilized. They were produced and kept under greenhouse conditions (25 ± 5 °C, 14:10 h, L:D photoperiod) until they were used for bioassays.