Influence of European Corn Borer (Lepidoptera: Pyralidae) Feeding on Various Stages of Field Corn in Kansas

Abstract

The impact of second-generation European corn borer (ECB), Ostrinia nubilalis (Hübner) stalk tunneling on yield reductions in corn, Zea mays L., was investigated for the Kansasproduction system. The stage of corn development when larval tunneling was initiated, vertical location of larvae on the plant, and number of larvae per plant were variables in the study. The probability of ECB larval occurrence at nodes above ground level was highest on the ear node; larval frequency decreased rapidly as distance increased from the ear node. Acrossall fields, the average probability of larval occurrence per stratum was 18.4, 59.5, and 22.1% for the bottom, middle, and top strata, respectively. A significant negative linear relationship between grain yield and level of infestation in the bottom and middle strata was fitted for all plant stages, with the exception of bottom-dent in 1981 and middle-dough in 1982. No relationship was seen between grain yield and level of infestation in the top stratum regardless of plant stage. The relationship between percentage yield reduction and cumulative corn growing degree-days (GDD) remaining to corn physiological maturity was described using a second-degree polynomial equation. Maximum potential yield reduction as a result of tunneling initiated by third-instar larvae was predicted to occur when ca. 35.7% of the corn GDD remained to physiological maturity. This coincided approximately with initiation of the blister stage. The percentage yield reduction per borer decreased as tunneling was initiated nearer to physiological maturity. Larval tunneling initiated during the pollination period of corn development appeared to have a smaller effect on yield than tunneling initiated near blister stage.