Suitability of Ectomyelois ceratoniae Zeller (Lepidoptera: Pyralidae) as host for two local Trichogramma species (Hymenoptera: Trichogrammatidae) and possible implications on biological control programs.

Abstract

In this study, laboratory tests were conducted to evaluate the suitability of Ectomyelois ceratoniae (Zeller) eggs as host for the development of two Trichogramma species: Trichogramma cacoeciae (Marchal) and Trichogramma bourarachae (Pintureau and Babault) (Hymenoptera: Trichogrammatidae) collected in Tunisia and reared on Ephestia kuehniella Zeller eggs. We also studied effects of five different temperature regimes (15, 20, 25, 30 and 35°C) on the biological traits of these two parasitoids. Results showed that eggs of E. ceratoniae were more suitable for the development of T. bourarachae. The number of parasitized eggs (15.46±2.04) as well as the emergence rate (95.78±5.10) was significantly higher compared to T. cacoeciae. For both Trichogramma species, the highest parasitism rate was observed at 30°C. At 35°C, the mean number of parasitized eggs (32.06±13.32) and the longevity (4.03±0.56) of T. bourarachae females were significantly higher compared to T. cacoeciae. The developmental time of both Trichogramma species was shorter at higher temperatures. The emergence rates were similar and relatively high in all tested temperature ranging from 80.48% to 97.92% for T. bourarachae and from 92.03% to 99.33% for T. cacoeciae.