Behavioral responses of the three Trichogramma species to different odor sources

Abstract

Tuta absoluta Meyrick (Lepidoptera: Gelechiidae), commonly known as the tomato borer, represents one of the tomato main pests since it had been explored. Eggs of the T. absoluta moth on tomato plants can be parasitized by variety species of Trichogramma as T. brassicae, T. evanescens and T. embryophagum. This study was conducted to test the behavioral responses of parasitoids to infested plants, herbivore induced plant odors from plants infested with T. absoluta and Bacillus thuringiensis (Bt treated plants) in an airflow Y-tube olfactometer. Odors emitted by tomato plant elicited a behavioral response from females of Trichogramma species. The results showed that parasitoid T. embryophagum females have been positively attracted to the healthy tomato plants (60%) comparing with clean air jar, T. brassicae, T. evanescens and T. embryophagum females have been positively attracted to the tomato plants infested with T. absoluta eggs/larvae (65%, 60% and 60%) comparing with non-infested plants female parasitoids were not attracted, and had a negative response, experiments preference ability to use Trichogramma spp. to control T. absoluta eggs. Trichogramma spp. females were consistently weaker toward Bt spray on tomato plants, that refer there are no effect from using Bt on control T. absoluta eggs.