Characteristics Of Parasitism Of Plutella Xylostella (Lep., Plutellidae) By Oomyzus Sokolowskii (Hym., Eulophidae)

Laboratory and greenhouse studies were conducted on Oomyzus sokolowskii Kurdjumov, a parasite of the crucifer pest Plutella xylostella ( L.). O. sokolowskii preferred the 3^rd and 4^th instar P. xylostella larvae over fresh pupae for parasitization. It is thus a larval parasite. Within the range of 10?C to 35?C, parasitism was positively correlated with temperature. High parasitism at temperatures of 30?C and 35?C indicates that this insect is suitable for the control of P. xylostella in the tropical lowlands. In a no- choice test where only fresh pupae of Cotesia plutellae Kurdjumov, another potentially competing larval parasite of P. xylostella, were offered, O. sokolowskii failed to parasitize pupae of C. plutellae. In a choice test where the 4^th instar P. xylostella larvae and fresh C. plutellae pupae were offered, O. sokolowskii parasitized only P. xylostella larvae. This parasite, therefore, is not a hyperparasite of P. xylostella. When C. plutellae-ovvposited P. xylostella larvae were offered at intervals, O. sokolowskii, parasitized only freshly oviposited host larvae. The longer the period that elapsed after C. plutellae oviposition of P. xylostella larvae, the lesser was the parasitism of these larvae by O. sokolowski.