Vol. 4, Issue 1 (2019)
Establishment of Telenomus isis polaszek (Hymenoptera: Scelionidae), an exotic egg parasitoid of noctuid stem borer pests in maize production systems in Kenya
Author(s): Esther Abonyo, George Ongámo, Catherine Lukhoba, Gideon Nyamasyo, Pierre Bruno
Abstract: The noctuid Busseola fusca forms a major proportion of the stem borer pest community in Kenya and various management initiatives including importation and release of egg parasitoids have been undertaken. Telenomus isis Polaszek, a noctuid stem borer egg parasitoid endemic to West and Central Africa was released in Kenya in 2005 to manage B. fusca in Wundanyi and Eldoret. Since the releases, their establishment status remains unknown. This study was undertaken to assess the parasitoid’s establishment and fields with maize at pre-tasselling stage around the release sites were inspected. Three egg parasitoid species; the indigenous Telenomus busseolae Gahan and Trichogrammatoidea lutea Girault and the exotic T. isis were recovered from survey sites. The establishment of T. isis in Kenya is hereby confirmed, though the parasitoid was only present in release fields in both localities. Results of this study also revealed changes in egg parasitism (from parasitoid pre-release figures) with a significant reduction in Eldoret (V=326; p=0.00072). In Wundanyi, a significant increase in egg parasitism was recorded (V=211; p=0.00035). Mean egg parasitism was significantly different between the localities (W=57; p=6.8e-10). Mean discovery efficiency in Wundanyi was significantly higher (55.4±6.1%) than in Eldoret (8.9±2.2%) (W=87; p=6.08e-095). There was no significant difference in parasitism efficiency between the two localities (W=397, p=0.061).