Does varying cowpea spacing provide better protection against cowpea pests?

The incidence and damage by PSBs in both varieties did not vary significantly (P<0.95, df=15 and P<0.18, df=15, respectively) with variation in plant spacing, but their damage contributed to the reduction of total grain yield. Pod yield increased with fewer insects as plant spacing increased from 0.8 to 1.5 m. Optimum plant spacing was different for the four insect pests. Aphids were less of a problem when plant spacing was less than 0.8 m, whereas a spacing of 1.0-1.5 reduced flower thrips and the pod borer.