Morphological Study and Its Changes in Immature Stages of Parasitoid Wasp Trichogramma brassicae (Hymenoptera:Trichogrammatidae) on Ephestia kuehniella (Lepidoptera :Pyralidae)

In spite of increasing the use of applied research in Trichogrammatidae family, study the morphology of the immature stages of the species seems to be necessary and important. One of the important biological control agents against numerous pests of Lepidoptera is Trichogramma brassicae Bezdenko (Hymenoptera: Trichogrammatidae). In the present study, biological traits including the lengths of the developing period of the immature stages, morphological traits were measured in each immature stages of Trichogramma brassicae Bezdenko (Hymenoptera: Trichogrammatidae) including larvae, prepupae and pupae, as well as mean body length and width and compound eyes spacing by dissecting of parasitized host egg. At 25± 1°C, an average of the larval stage lasted a bit more than two days, the pre-pupa stage was 2.5 days and the pupa stage was 3.5- 4 days. Neonate Larvae, with an opaque body, which is lack of external morphological characters had the highest mean length ((mean= 0.98± 0.002 SEM) and width (mean= 068±0.001 SEM) of the body in comparison with other immature stages of development. The emergence of urate disks, promising the being the prepupa stage, appeared approximately 52 hours after egg-laying. Pupa was exarate and without cocoon. As there are very few studies on the immature stages of Trichogramma parasitoid, the results of this study can be used as the basis for other future studies.