none. Seasonal abundance of diamondback moth (DBM), Plutella xylostella (L.) (Lepidoptera Plutellidae), the parasitoid Diadegma insulare (Cresson) (Hymenoptera: Ichneumonidae) and a major predator Pardosa milvina (Hentz) (Araneae: Lycosidae) was monitored in field plots of esfenvalerate-treated, Bacillus thuringiensis-treated and untreated collards (Brassica oleracea L.). Diamondback moth populations were kept below the action threshold ( lt 1.0 larva per plant) by indigenous natural enemies in plots where applications of esfenvalerate were avoided. Late season resurgence of DBM populations occurred in esfenvalerate-treated plots in each of three seasons. Numbers of DBM larvae and pupae were significantly lower (P lt 0.05) in all three seasons in Bacillus thuringiensis-treated plots and in two of three seasons in untreated plots. Percent parasitization was significantly lower (P lt 0.05) in esfenvalerate-treated plots during the late season resurgence in two of three seasons. Esfenvalerate significantly reduced (P lt 0.05) numbers of P. milvina, one of the most abundant predators of diamondback moth.