SEASONAL ABUNDANCE AND RESPONSE OF DIAMONDBACK MOTH, PLUTELLA-XYLOSTELLA (L) (LEPIDOPTERA, PLUTELLIDAE), AND NATURAL ENEMIES TO ESFENVALERATE AND BACILLUS-THURINGIENSIS SUBSP KURSTAKI BERLINER IN COASTAL SOUTH-CAROLINA

Seasonal abundance of diamondback moth (DBM), Plutella xylostella (L.) (Lepidoptera: Plutellidae), the parasitoid Diadegma insulare (Cresson ) (Hymenoptera: Ichneumonidae) and a major predator Pardosa milvina (H entz) (Araneae: Lycosidae) was monitored in field plots of esfenvalera te-treated, Bacillus thuringiensis-treated and untreated collards (Bra ssica oleracea L.). Diamondback moth populations were kept below the a ction threshold (< 1.0 larva per plant) by indigenous natural enemies in plots were 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 signifi cantly lower (P < 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 < 0.05) in esfenvalerate-tr eated plots during the late season resurgence in two of three seasons. Esfenvalerate significantly reduced (P < 0.05) numbers of P. milvina, one of the most abundant preators of diamondback moth.