In 1981 and 1982, three crop protection regimes were compared with an unsprayed control for cowpea grown alone and in mixtures with maize, sorghum and cotton. Unsprayed cowpea in mixtures with maize had yields which suggested some pest escape in 1981 but not in 1982. When sprayed, only the maize–cowpea mixture showed much yield advantage over sole crops. For maize–cowpea in 1983, a very dry year, only the alternate row mixtures showed a yield advantage and three spray applications gave cowpea yields as good as those resulting from six applications. The late, photosensitive cowpea variety Acq 1696 had better yields than the medium maturity TVx1948·01 F in the mixed crop but was greatly inferior as a sole crop.