LAUSR

Functional response is one of the most informative ways to study the density responsiveness of a natural enemy to the target pest. Tuta absoluta (Meyrick), one of the most destructive pests of tomato, has recently invaded India. In the present study, we investigated the functional response of Trichogramma achaeae Nagaraja and Nagarkatti, Trichogramma pretiosum Riley, Trichogramma chilonis (Ishii) and Trichogramma pieridis Nagaraja and Prashanth to the pest. All the parasitoids exhibited type II functional response to T. absoluta eggs. The handling time was minimum for T. achaeae (1.6 h) followed by T. pretiosum (1.86 h) T. chilonis (2.16 h) and T. pieridis (2.65 h). Theoretical maximum number of host eggs that could be parasitized in 24 h by each female of these parasitoids was estimated to be 16.23, 13.24, 11.05 and 8.97, respectively. Functional response parameters indicate that T. achaeae and T. pretiosum were more efficient parasitoids than the other two species against T. absoluta. It is, therefore, important to consider these tested egg parasitoids for biological control based integrated pest management programmes for this invasive pest.