Corn Borer

The corn borer is the most economically important maize pest in Germany.

The first larvae of these microlepidoptera feed on maize leaves and then drill into the stem and the cob of the maize plant. In cooler, temperate climates common in Europe, the corn borer completes only one generation per year. Larvae hibernate in maize stubble, pupating in the spring. It was was brought to North America from Europe around 1910.

There are two known strains (Z and E). In Germany the E strain is found almost exclusively in a weed: the mugwort. The Z strain is today found mainly in the maize-growing regions of southern Germany and in the Oderbruch region. The infestation limit is continually shifting towards the north-west. The first infestation was found in Lower Saxony in 2006. In Mecklenburg-Western Pomerania the little moth has already reached the Baltic coast.

There are several strategies for corn-borer control:

• mechanical methods involve chopping up the plant remains left on the field and ploughing them under
• Spraying chemical insecticides
• Biological control: Trichogramma (ichneumon flies)
• Bacillus thuringiensis (Bt) toxin, either in the form of preparations applied externally as a spray or the transgenic introduction of the Bt gene into maize plants

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