Comparing two saturniid defoliators of Holarrhena floribunda and Ekebergia sengalensis, respectively, with notes on their natural enemies

Summary

The larvae of two saturniid moths, Imbrasia epimethea and Bunea alcinoe, seriously defoliate Holarrhena floribunda (G. Don) Dur & Schinz, and Ekebergia senegalensis A. Juss, respectively. The larval stages, life history and feeding habits of both pests are described and particular reference is made to their comparable characters. I. epimethea appears restricted to H. floribunda. B. alcinoe has a wide host range, including some species of mahogany and eucalypts, Balanites aegyptica Linn., Cussonia barteri Seeman, all from the northern parts of Nigeria and Fagraea fragrans Thunb, Cleistopholis patens Benth. and Spondias mombin Linn. from the southern parts. E. senegalensis seems to be the primary or most preferred host in the south. Larvae of B. alcinoe can be grouped by differences in basic ground colour, into northern forms (dark larval skin), and southern forms (mainly orange-red larval skin). Observations on the natural enemies of both insects, made up mainly of two orders—Diptera and Hymenoptera, are reported. Parasitism is likely to help reduce the insect population and foresters may therefore feel reassured about the dangers of attack even in the event of large-scale planting of the host trees.