Preliminary Studies on the Occurrence of Stem Borers and the Incidence of Stalk Rot under Varying Plant Population Densities in Maize

Abstract

A field experiment was carried out to study the occurrence of stem-borers and the incidence of stalk rot under varying population densities (64,000, 32,000, and 21,333 plants/ha) of two common cultivars (TZSR-Y and DMRZ-Y) of maize. Whereas the percentage of plants with stem borers infestation and those with stem tunnels increased with decrease in population density, the percentage of plants with stalk rot, but without stem borer infestation, was found to be higher in high density plots. In low-density plots significant predisposition of plants to stalk rot infection was observed. Heights of plants of the two cultivars was apparently the same but a significant reduction in the height of infested and infected plants, compared to those without, was recorded. While the number and weight of cobs and grains per plot were apparently higher, in low-density plots, expressing the results per individual plants, however, showed that those in low-density plots produced heavier cobs and more grains. The results showed that the medium plant density was more desirable from both disease and pest control points of view.

JARD Vol. 1 2001: pp. 67-74