© 2022, The Author(s).Background: This study was conducted to investigate host stage preference and demographic parameters of the parasitoid species, Leptomastix dactylopii Howard (Hymenoptera: Encyrtidae), the parasitoid of vine mealybug Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae), an important pest in vineyards in many countries. Results: The results revealed that L. dactylopii was not able to develop on the 1st and 2nd nymphal instars of P. ficus and preferred female mealybugs as the host to the 3rd nymphal instar. Hind tibia length and head capsule width of both female and male parasitoids emerged from the mummies of mealybugs parasitized in the female stage were greater than the values of the parasitoids emerged from the mummies of mealybugs parasitized in the 3rd nymphal instar. Demographic parameters of the parasitoid were calculated with the use of development and reproduction data obtained from life table of L. dactylopii. The intrinsic rate of increase was determined as (r = 0.1527 d−1), finite rate of increase as (λ = 1.1650 d−1), net reproductive rate as (R0 = 46.0667 offspring), and mean generation time as (T0 = 25.0830 d). Conclusions: It was concluded that L. dactylopii was able to develop, especially in the female and in the 3rd nymphal instar of P. ficus and could be used for biological control of the vine mealybug.