Evaluation Of Tetrapleura Tetraptera (Schum & Thonn) Fruit For The Control Of Balanogastris Kolae (Desbr.) Infesting Stored Kolanuts

Abstract

The efficacy of the powder of Tetrapleura tetraptera fruit (Schum & Thonn) in the control of the kola weevils, Balanogastris kolae (Desbr). was investigated in the laboratory. The plant material was tested at three concentrations 20, 40 and 80 g powder/kg of cured kolanuts. These were compared with the untreated nuts (control). T. tetraptera powder was toxic to B. kolae, especially at 40 and 80 g/kg concentrations. At 40g/kg and 80g/kg concentrations, T. tetraptera powder caused high mortality (100%) on introduced weevils after 7 and 14 days, respectively. The level of weevil damage observed on nuts treated at concentration of 40 g and 80 g were significantly lower than at 20 g concentration and the control, when parameters such as feeding holes, oviposition holes and percentage damaged were considered. Although the colour and texture of nuts were not affected by the treatments, the flavour from the application was slightly felt at the 80 g/kg level.


Key words: Balanogastris kolae, Tetrapleura tetraptera, cured kolanuts, weevil damage

Ife Journal of Science Vol. 7(1) 2005: 27-30