The efficacy of different rates (5, 10 and 20% w/v) and application schedules (2, 4 and 6 weekly spraying) of Syzigium aromaticum (L.) Merr and Perr extracts was investigated in two years field trials for the control of the legume pod borer, Maruca vitrata Fab. and the coreid bug, Clavigralla tomentosicollis Stal. on cowpea plants. The different concentrations and spraying schedules of aqueous extracts of clove, S. aromaticum exhibited considerable reduction on the populations of M. vitrata and C. tomentosicollis as compared to the untreated check. Of the clove extract treatments tested, 10 and 20% rates with four and six weekly applications were superior to 5% rate at all weekly schedules. Pod damage was equally reduced and there was a substantial increase in grain yield at higher concentrations and more frequent sprayings but their values were inferior to the synthetic insecticide treatment. Clove extract could form an integral part of a new approach to pest control on arable crops in small farm holdings commonly found in limited resource farmers` enterprises in Africa.
Oparaeke and Alphonsus Mbonu , 2006. The Potential for Controlling Maruca vitrata Fab. and Clavigralla tomentosicollis Stal. Using Different Concentrations and Spraying Schedules of Syzigium aromaticum (L.) Merr and Perr on Cowpea Plants. Journal of Plant Sciences, 1: 132-137.