Vol. 2, Issue 5 (2017)
Application of Afrostyrax lepidophyllus and Piper guineense extracts and their mixtures in the control of Cowpea weevil Callosobruchus maculatus (F.)
Author(s): Onekutu A, Iboyi MO, Otakpa EO
Abstract: The effects of sole application of Afrostyrax lepidophyllus and Piper guineense extracts and their mixtures on the cowpea weevil Callosobruchus maculatus (F.) was investigated under laboratory conditions. The plant extracts were combined in different ratios of 1:1, 1:0, 3:2 and 0:1 in the form of A. lepidophyllus: P. guineense and applied to the seeds at the rate of 2ml/30g and 0.5ml/ 10 cowpea seeds. A. lepidophyllus extract (1:0) recorded an adult mortality of 100% four days after the treatment application similarly, P. guineense (0:1) extract also recorded an adult mortality of 100% but this occurred on the sixth day after treatment application while, the treatment ratio 3:2 was found to significantly affect adult mortality after the fourth day of post treatment (P<0.05). However, P. guineense extract was found to be the most effective in deterring the adult weevils from emerging while the treatment ratio 3:2 also significantly deterred adult emergence in the weevils (P<0.01). The ovipositon deterrence test revealed that the treatment ratio 3:2 was most effective in deterring oviposition in the bruchids this is followed closely by the P. guineense extract (P>0.05). Similarly, the highest ovicidal effect was recorded with the 3:2 treatment ratio while P. guineense extract also had a significant effect on the bruchid ova (P<0.05). The study therefore concludes that A. lepidophyllus and P. guineense extracts (3:2) have synergistic effect on cowpea weevil C. maculatus and can therefore be used to control these weevils in stored cowpea seeds.