Efficiency of female age of egg parasitoids on parasitism of Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) eggs of various ages.

The use of egg parasitoids in the biological control of insect pests is a promising technique in integrated pest management. However, there is little information on the effects of parasitoid female age and host egg age on parasitization rates specifically on the behaviour of the egg parasitoids such as Trichogramma pretiosum Riley and Telenomus remus Nixon which can have substantial effects on parasitism towards insect pest eggs. Thus, this communication evaluated the relationships between the age of the parasitoid and host egg on the parasitism of Spodoptera frugiperda eggs by T. pretiosum and T. remus in three independent bioassays. In the first and second bioassay, two egg parasitoids (T. pretiosum and T. remus) females were grouped by age in days (ranging from 1–6 and 1–10 days old for T. pretiosum and T. remus, respectively) and were offered 100 eggs of S. frugiperda per treatment for 24 h separately. In the third bioassay, 100 eggs of S. frugiperda of different ages (24, 48 and 72 h old) were offered separately to T. pretiosum and T. remus females for 24 h. The variables such as the number of eggs parasitized, parasitoid emergence (%) and female progeny were evaluated. The results indicated that as the age of the T. pretiosum increases, per cent parasitism and adult emergence decreases but age of T. remus females did not affect the number of S. frugiperda eggs parasitized or the emergence of the progeny. However, the sex ratio was more male-biased in the progeny of 1- and 2-day-old females compared to older wasps in the case of T. remus. In the third bioassay, the highest parasitism was observed in 24- and 48-h-old eggs and the per cent emergence decreased with increasing female age. [ABSTRACT FROM AUTHOR]