Evaluation of Trichogramma brassicae native strains as egg parasitoid of tomato leafminer, Tuta absoluta (Meyrick) in the laboratory conditions

The tomato leafminer, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is a devastating pest of tomato, originating from South America. As the key pest of tomato, it occurs throughout the all stages of host plant and its damage and leads to the total destruction of the product. One of the controlling measures of T. absoluta is the use of biological control agents, such as Trichogramma wasp (Hym.: Trichogrammatidae) as the egg parasitoid. Laboratory tests were undertaken to evaluate the potential of 6 Iranian strains of T. brassicae to control T. absoluta. A completely randomized design with 12 replications was employed to evaluate treatments. Tomato (Nanhemz 6189) was used as host plant and all experiments were carried out at 25±1˚C, 70±10 % RH and 16:8h (L:D). Mated Trichogramma females aged 12-24h, were placed individually on an infested tomato leaflet harbouring 30 T. absoluta fresh eggs (15 eggs in both sides of leaves, equally) in a plastic glass (11×8.5cm). The parasitoid wasps were then removed from the glass after 24 hours. After five days the parasitized eggs were counted and the parasitism rate of T. absoluta eggs by T. brassicae strains was compared. The highest and lowest parasitism rate was achieved as 53.89±9.34 and 6.94±4.05 percent for Baboulsar and Some-e-Sara strains, respectively. The average of T. absoluta eggs parasitized by Trichogramma brassicae strains was not significantly different on both sides of tomato leaves.