1. Introduction
The diamondback moth, Plutella xylostella (L.) (Lepidoptera:
Plutellidae), is a serious pest of cruciferous vegetables worldwide
[1], and the larvae cause extensive damage by feeding voraciously
on foliage [2]. The annual losses from the control of P. xylostella
were calculated at $US 1.4 billion worldwide [3]. To ensure yields
of cruciferous vegetables inmany countries, insecticide application
targets this pest for control [3].