Efficacy of Basil-Cabbage intercropping to control insect pests in Benin, West Africa

Cabbage (Brassica oleracea L.) is a common vegetable whose production is severely limited by insect pest pressure in Western Africa. This study was conducted during the dry and rainy season in the south Benin to evaluate the potential of tropical basil (Ocimum gratissimum L.) for repelling cabbage pests (Hellula undalis Fabricius, Plutella xylostella L. and Spodoptera litto-ralis Boisduval). In a complete randomized block design with four replicates, the insect infestation were compared between three association modalities: (i) cabbage intercropped with tropical basil, (ii) cabbage plots surrounded by tropical basil and (iii) control (no basil in the cabbage area). The presence of tropical basil near cabbage plots significantly reduced insect pest abundance on cabbage. Damages were also less important on cabbage intercropped with tropical basil. Among both intercropping modalities, alternate rows showed the best results in terms of reducing pest populations and damages than compared to cabbage plots surrounded by tropical basil.