Effect of Pyrausta nubilalis (Hbn.) on the Growth of Leaves and Internodes of Field Corn1

Abstract

A 4-Year study on the effect of infestation by the European corn borer (Pyrausta nubilalis (Hba.)) on the growth of corn plants shows the following points: 1) Borer infestation adversely affects the elongation of the plants, results in smaller leaves, shorter internodes, and a delay in both tackling and silking. 2) Reduction in size of leaves increases progressively toward the tip of the plant. 3) The reduction in the length of internodes, however, is greater in internodes near the ear and tassel than in other internodes. 4) The decrease in the length of internodes began when only the leaf blades were injured by the borers, and without the physical destruction or obstruction of the vascular bundles in the stalk. 5) These facts indicate a need for investigations on (a) feeding activates of the young larvae and plant reaction to such feeding; (b) whether a phytotoxic secretion may be involved; and (c) the possibilities of interrelationships between micro-organisms and corn borer infestation.