EVALUATION OF CERTAIN MAIZE VARIETIES AGAINST THE PINK BORER, Sesamia cretica Led. AND THE EUROPEAN CORN BORER, Ostrinia nubilalis Hub.

Abstract

Maize (Zea mays L.) is an important cereal crop in Egypt. This crop is attacked by many insects, specially the pink borer, Sesamia cretica Led. and the European corn borer, Ostrinia nubilalis Hi.ib. The present study was conducted to evaluate the relative susceptibility of four commercial maize varieties, two single crosses (SC 10 and SC 129), 3W31 0, an open pollinated variety (Giza 2) and an inbred line Sk36 to infestation with the two previous insect pests under natural tield infestation at Kafr El-Sheikh region during three successtve seasons; 1998, 1999 and 2000. The maize morphological, chemical and physiological characteristics which related to susceptibility to infestation were studied. Also, effect of sowing dates was investigated. The results were summarized as follows:

1. Relative susceptibility of some maize varieties to natural infestation with the two corn borers: 1.1. Sesamia cretica Led.

Two single crosses, SC 10 and SC 129, an open-pollinated variety; Giza 2, three way cross 3W310 and an inbred line Sk 36 was evaluated to S. cretica infestation. They were sown on 20111 April at the time of high S. cretica infestation. The level of infestation was determined by two ways.

A. Numbers of immature stages; egg masses, larvae and pupae: B. Percentage of dead hearts. Results obtained indicated that:

In April plantation, 3W31 0 was the most preferred variety for egg laying (0.7 egg masses/20 maize plants) followed by scl29 variety, while