Biology of Venturia canescens, a Larval Parasitoid of Carob Moth, Ectomyelois ceratoniae under Laboratory Conditions

The carob moth, Ectomyelois ceratoniae zeller (Lep.: Pyralidae) is the most important pest of pomegranate orchards in Iran. This current research was carried out to study the biology of Venturia canescens Gravenhorst (Hym.: Ichneumonidae) as one of its larval parasitoids. Laboratory studies were conducted on the immature developmental time, adult longevity, functional response, parasite progeny production and host stage preference of V. canescens. At 25 ± 1 ˚C, the immature developmental time (egg to adult) was 31.06 ± 0.59 d, 27.9± 0.86 d and 22.86 ± 0.3d for third, fourth and fifth host age respectively. Adult females survived on the average 15.87± 0.31, 11.77± 0.21, and 4.07± 0.14, 2.7± 0.14d at 25 ˚C when provided with honey and water, honey only, water only or no food source, respectively. Female V. canescens typically oviposited into higher larval stages, with significantly more fifth than the third or fourth instars parasitized. Logistic regression indicated a type II functional response on the fifth host larval age. The oviposition activity peak ooccured on the 8th day following emergence and when provided with honey and 10% sucrose solution. The results finally revealed that the fifth host larval age may constitute the best stage for mass production of the parasitoid.