Plant extracts

Six acetone extracts of Annona senegalensis root-bark; Tephrosia vogelii root-bark; stem-bark, leaf and seed; Tephrosia candida seed; and two aqueous residue extracts of neem seed kernel and Annona muricata seed kernel were tested for bioactivity against Rasdtrococcus invadens Williams at different concentrations with three replications. The six acetone extracts were highly toxic to adult female R. invadens in the combined mode experiment. T. vogelii stem-bark, followed by its seed; A. senegalensis root-bark and T. candida seeds extracts, was most insecticidal to the mealybug.

The effect extract of Ocimum gratisimum L., Carica papaya, Azadirachta indica A. Juss, Vernonia amygdalina and Bixa orellana L. on pathogenicity and reproduction of Meloidogyne incognita race 3, the causal organism of the root-knot disease of cacao was investigated in the greenhouse. Leaf extracts were prepared by blending and filtration of 25g of chopped leaves in 100ml of distilled water. Each cocoa seedling in a naturally infested soil received 40ml water extract of the leaves. Nematode populations were reduced by the application of the extracts in a descending order of A. indica, B.