Stem borer damage in maize as affected by host plant density

Maize grain production in Nigeria is the collective effort of several growers individually cropping small areas. In these farms, maize stands are at suboptimal densities, soil fertility is low and crop loss from pests is high. Consequently, grain yields are characteristically low. By planting maize at closer spacing than the current standard, 90 x 25 cm, Fayemi (1963), Chinwuba (1967), and Okigbo (1972) were able to raise grain yield. However, the effect on pest population in Nigeria of increasing host plant density has received little research attention. Cromartie (1975) showed that host plant density and arrangement affect insect population dynamics. Other reports by Ficht (1932), Finch & Skinner (1976), Ralph (1977), Zepp & Keaster (1977), Adesiyun (1978) and Mayse (1978) indicate differential insect colonization, establishment and damage on host plants sown at different densities.