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.
An investigation was undertaken to assess the effect of Neem-fortified Cocoa pod husks soil amendment against the root-knot disease caused by Meloidogyne ingonita on cacao seedlings, Theobroma cacao L. cv. F3 Amazon. Cocoa pod husks (CPH), combined use of Neem leaves and CPH, and Neem seeds plus CPH decreased the number of juveniles and galling due to Meloidogyne incognita. The greatest decrease was obtained with Neem seed-fortified cocoa pod husks with a corresponding increase in the plant growth.