Economic analysis of habitat manipulation in Brassica pest management: Wild plant species suppress cabbage webworm

Chemical insecticide application has been the most widely used form of insect pest management in last six decades and resulted well-documented negative impacts. Habitat manipulation based on intercropping to exert direct effects pests promote biological control explored various systems as a more sustainable option. A range intercrop plants have evaluated, with many studies reporting successes terms enhanced natural enemy density, reduced numbers and, less commonly, crop loss. Economic benefit cost-effectiveness are frequently explored, despite importance these criteria farmer adoption scope scale. Here we quantify contrasting experimental habitat treatments densities pest, cabbage webworm, Hellula undalis Fab. (Lepidoptera: Crambidae), yield quality, profitability cost: ratio Brassica oleracea var. capitata (Brassicaceae) production system West Africa. Six wild plant species were evaluated intercrops suppression. Ageratum conyzoides, Tridax procumbens (Asteraceae), Crotalaria juncea (Fabaceae), Cymbopogon citratus (Poaceae), Lantana camara (Verbenaceae) Talinum triangulare (Talinaceae) plantings compared no-plant treatment randomised block experiment over three growing seasons Ghana. Costs gathering propagules establishing each recorded, was market value from treatment, allowing calculation precise ratios. larvae numerous treatments. The had higher undamaged yields control. Reflecting this, establishment costs, better ratios than control, ranging 1:2.8 for C. 1:46.6 A. conyzoides. These findings provide an important evidence base considering economic case highlight that identity this type agricultural intervention major effect outcome.