The aqueous extracts from Tephrosia vogelii, Syzygium aromaticum and Croton dichogamus were assessed for the control of Crocidolomia binotalis in the Brassica oleracea field. Synthetic pesticide, water and water plus soap were used as positive and negative controls, respectively. Results show that the aqueous extracts from S. aromaticum, C. dichogamus and T. vogelii were significantly (P ≤ 0.05) as effective as synthetic pesticide in controlling C. binotalis in weeks 1 and 2 after treatments. On weeks 3, 4 and 5, the population of C. binotalis was significantly (P ≤ 0.05) lower in 5% concentration of aqueous extract of the mixed plants compared with aqueous extracts from the individual plants. However, the aqueous extracts from individual plant at 1, 5 and 10% concentrations possessed significantly (P ≤ 0.05) lower number of C. binotalis compared with negative controls. Also, the 5% of extracts of the mixed plants had significantly (P ≤ 0.05) lower percentage damage of B. oleracea comparable to synthetic pesticide in weeks 1 to 5 after treatment applications, respectively. The aqueous extracts of each individual plant at 10% exhibited less percentage damage of B. oleracea compared with the 5 and 1% concentrations of the extracts. However, 1 and 5% of the extracts of the individual plant reduced the percentage damage of B. oleracea crops compared with negative controls. Therefore, the aqueous extracts of mixed plants at 5% concentration and individual plant at 10% concentration can be used by smallholder cabbage growers to control C. binotalis larvae in the field.
