Hexane extracts from Tephrosia vogelii Hook. f. protect stored maize against the weevil Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae)

Powdered dried leaves of Tephrosia vogelii (Hook) (Leguminosae: Papilionoideae) were extracted using hexane, acetone, and ethanol. The extracts were tested for their ability to protect stored maize from damage by Sitophilus zeamais Motschulsky, the major maize weevil in Africa. The acetone and ethanol extracts were ineffective, but the hexane extract had a relatively high efficacy, producing within 7 days a slow reduction in adult survival, reduced numbers of eggs laid and reduced numbers of F₁ progeny, resulting in seed damage averaging 8.8% compared with 98.6% in the untreated control after one generation. This hexane extract provided control of S. zeamais at a higher level compared with neem (the botanical control) but at a lower level compared with pirimiphos‐methyl (the synthetic control). These findings are discussed in the context of T. vogelii containing rotenoids.