Based on a systematic field investigation,the temporal and spatial niches of the diamondback moth(DBM),Plutella xylostella(Linnaeus)and major predatory enemies in spring cabbage fields were studied.The results showed that the diamondback moth had a narrow temporal niche breadth and a relative wide spatial niche breadth.This implied that the incidence of the diamondback moth had the characteristics of obvious peak-period and whole-plant damage.The temporal and spatial niche breadths of DBM had no significant...