STUDIES ON THE STRAINS OF TRICHOGRAMMA-EVANESCENS WESTWOOD (HYM, TRICHOGRAMMATIDAE) COLLECTED FROM DIFFERENT HOSTS IN NORTHERN MALDOVA

Biological and morphological characteristics together with electrophor etic patterns were compared for five strains of Trichogramma evanescen s W., collected from the eggs of Mamestra brassicae L., Ostrinia nubil alis Hb. and Agrotis segetum Schiff. in northern Maldova. Significant differences were observed in the biological characteristics including the proportion of female progeny, developmental period, longevity and fecundity. The strains also differed in the ratio of antennal hair len gth to the maximum width of flagellum in males. Patterns of esterase s ystems indicated that the strains differed in the mobility and intensi ty of esterase bands, All the strains had a strong preference for the host from which they were collected in the field. Crossing of the stra ins indicated that one strain was reproductively isolated. The results have application in selecting the strategy for establishing initial c olony in mass rearing of parasitoids and for research on Trichogramma ecology and evolution.