Received: 29-08-2023 / Accepted: 07-03-2024
This study aimed to investigate the parasitism rate of Encarsia sp.on B. tabacias well as the impact of host age, host density and parasitoid density on its parasitism. The survey on natural Encarsiaparasitism was conducted on the eggplant fields at Gia Lam, Hanoi at 7 days interval. The results showed that Encarsia sp.had the highest parasitism rate (58.57%) in the middle of June and declined afterward. The parasitoid and whiteflies were mass rearing in the laboratory and recorded for the parasitism rate in 24 hours with different host age (1st-4thinstar nymphs), host densities (5-80 nymphs(3rd-4thinstar)/ leave) and parasitoid densities (1-4 females/ 50 nymphs (3rd-4thinstar). Encarsia sp. reached the highest parasitised percentage at 3rdinstar nymph and lowest at 1stinstar nymph. As the host density increased the parasitism rate decreased, but the emerge rate increased, however. Nevertheless, parasitism increased with increased parasitoid density, but the average parasitism per female decreased. At densities of 1-2 female parasitoids the emerge rate was higher than at 3-4 female parasitoids.Overall, Encarsia sp. had high parasitism rate on the field and host age, host and parasitoid density influenced its parasitism.