Effects of temperature and humidity on some biological properties of the egg parasitoid, Trichogramma euproctidis Girault (Hymenoptera: Trichogrammatidae)

Trichogramma species are important egg parasitoids of many Lepidopteran pests. In this study, effects of four different temperature (15, 20, 25 and 30ºC) and three different humidity (30%, 60%, and 80%) conditions on some biological properties of the egg parasitoid, Trichogramma euproctidis (Girault) (Hymenoptera: Trichogrammatidae) were studied. The Mediterranean flour moth, Ephestia kuehniella (Zeller) (Lepidoptera: Pyralidae) was used as factitious host for T. euproctidis rearing. Adult longevity, pupation time, preimaginal developmental period, the total number of parasitized eggs, the number of emerged parasitoids, the number of emerged parasitoids per host egg, emergence ratio (%) and sex female ratio (%) of emerged parasitoids were calculated. Results have demonstrated that temperature and humidity significantly affected pupation time, preimaginal developmental period and the number of emerged parasitoids per host eggs. However, total fecundity, the number of emerged parasitoids eggs and adult longevity was affected by temperature. Interaction of temperature and humidity influenced all parameters. In addition, as the temperature increased, adult longevity, pupation time and preimaginal developmental period were decreased while the number of parasitized eggs was increased. The combination of 30ºC temperature and 80% humidity was found to be optimal in terms of the number of parasitized eggs, the number of emerged parasitoids and sex ratio while the combination of 20ºC temperature and 60% humidity was optimal for adult longevity. This study suggests that tested temperature and humidity combinations should be taken into account in mass rearing procedures of T. euproctidis for maximum performance in terms of tested biological properties. Key words: Trichogramma euproctidis, Ephestia kuehniella, egg parasitoid, humidity, temperature, biological properties