none Abundance of the larval and pupal stages of the diamond-back moth P. xylostella (L.), was estimated in a kale crop in 1980-1981. Samples were taken every 3rd day; the sampling unit was the leaf. The sampling universe was 500 plants of B. oleracea L. var. acephala D.C. The experimental area was situated at the "Estacao Experimental Fitotecnica de Viamao", Aguas Claras District, Viamao County, RS (RioGrande do Sul, Brazil). Mortality of the larval and pupal stages due to parasitoids was estimated along with host of abundance. Mortality was estimated independent of the abundance of the host, and only the 2 last larval stages of P. xylostella were considered. The complex of parasitoids consisted of 3 main species: the eulophid Tetrastichus sokolowskii Kurdjmov, the braconid Apanteles piceotrichosus Blanchard and the chalcid Spilochalcis sp. The occurrence of both P. xylostella and its parasitoids was restricted to a short period of the year (Dec.-Feb). The density of P. xylostella was low throughout the sampling period. Their scarcity might be attributed, at least in part, to the inadequate combined effect on fecundity of photoperiod and temperature. T. sokolowskii was the main parasitoid in both seasons. This is the 1st record of this species for South America.