CHANGES OF WEIGHT AND IN-KERNEL CONTENT VALUES OF MAIZE HYBRIDS (OCCITAN, COLOMBA, DK-471) AS A RESULT OF DAMAGING BY EUROPEAN CORN BORER (OSTRINIA NUBILALIS HBN)

Abstract

The research was conducted in the year 2001 on two fields sown with three different maize hybrids and was based on randomly chosen sample plots. The first survey was carried out on the field sown with hybrids COLOMBA and OCCITAN (total area 120 ha), the second survey was performed on 50 ha of hybrid DK-471. The assessment was focused primarily on the difference between the cobs developed by healthy and damaged maize plants with regards to their weight and the content of protein, fat and starch in the maize kernel. The hybrids unambiguously reacted to infestation by the European Corn Borer by cob weight reduction. The decrease of kernel fat content in the case of COLOMBA and that of the starch content in the case of OCCITAN displayed significant dependence on the degree of infestation by the European Corn Borer. The results of the survey verifiably showed that in both cases either metabolism, or incorporation of protein, fat and starch had experienced disorder. A close link has been ascertained between the growth of larvae population and the kernel-cob rate of the examined hybrids. The distribution and number of larvae significantly affected the weight of maize cobs of hybrid DK-471 and the quantity of the basic nutrient components (raw protein, fat and starch) incorporated in the kernel.