Abstract: A field studywas conducted to determine the most effective intercropping combination of chilli and maize to reduce the occurrence of Phytophthora blight ( PB) on chilli and Northern & Southern leaf blight (NSLB) on maize. The treatment combinations were MC₅M, MC₆M, MC₇M, MC₈M, MC₉M, MC₁₀M, M₁₀
and C₁₀ , (M, Maize; C, Chilli; 5 - 10, number of rows ofmaize or chilli per p lot). All intercrop combinations reduced incidence of both PB and NSLB significantly over their counterpart monocrops. The chillimaize combination of MC₅M had the most drastic effect in reducing PB on chillies while MC₁₀M proved to be the best
combination formanagement of NSLB in maize. The incidence of PB increased and that of NSLB decreased with increasing number of rows of chilli in the intercrop combination. The statistical analysis showed that all intercropping systems had greater yields and economic advantage over their monocrop counterparts. Intercrop combination ofMC5M had the greatest combined yield but smallest economic value whereas MC₁₀M had the opposite effect. Maize and chilli yields per plant increased gradually with the increasing rows of intercropped chilli. The programme establishes useful potential at farm-level for using interspecific diversity as means to improve control of PB and NSLB.

Key words: Chilli pepper, Maize, Intercropping, Disease management