Laboratory Production of Clusters of European Corn Borer Eggs for Use in Hand Infestation of Corn1

Abstract

To study the comparative effect of the European corn borer (Pyrausta nubilalis) in reducing the yield and quality of various strains and varieties of corn, it was found necessary that several different average borer populations or borer levels should infest each strain of corn. It was found necessary to produce, in the laboratory, clusters of corn-borer eggs with which to hand-infest the corn plants in order to obtain the levels of infestation desired. The most practical method developed for producing egg clusters in the laboratory was to place infested cornstalks in an emergence cage as a source of moths, to force the moths to lay their egg clusters on waxed paper suspended in specially designed oviposition cages, to cut from the waxed paper small disks, each bearing an egg cluster, and to pin these disks on common pins, which later are pinned on the corn leaves. A formula is presented for use in estimating the number of eggs which should be placed on each plant to obtain a definite number of mature borers. The estimated cost of producing the egg clusters was about 59 cents per 100 clusters for an experiment continued over a period of one year or 44 cents per 100 clusters when extended over three years.