Who’s afraid of the corn rootworm?: Baykomm

Special Story

Who’s afraid of the corn rootworm?

The corn rootworm. Even its name is unattractive. And the damage it does to corn plants is even less pleasant.

The pest that does the most damage to corn crops all over the world is at Germany's door. A product from Bayer CropScience can help - and has been given special regulatory approval.

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The pest that does the most damage to corn crops all over the world is at Germany’s door. A product from Bayer CropScience can help – and has been given special regulatory approval.

As the name suggests, yellowish-white larvae hatch from the corn rootworm beetle’s eggs and make straight for the next corn plant, where they eat their way through the roots. As a result, water uptake and the transport of nutrients to the higher parts of the plant are interrupted, and the roots are weakened to such an extent that one day they become unable to provide adequate support for the growing plant. The corn plant bends near the ground, a phenomenon known as gooseneck lodging, and the plant may even fall over and die.

But that’s not all. After a brief pupation phase, beetles between five and seven millimeters long emerge in the summer and launch a second attack on the corn, this time eating the leaves and silks. The crop is diminished further. Finally, in late summer, the females lay several hundred eggs close to the plant.

The larvae emerge in May, and if more corn has been sown on the same field, the cycle starts all over again.

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The larvae of the corn rootworm

Throughout the world, the corn rootworm is considered to be the most harmful corn pest in economic terms. It has been ravaging the USA for many years, having migrated from Latin America. The loss of yield and the cost of treating crops against the corn rootworm in the USA mean expenses totaling around one billion U.S. dollars every year.

The beetle was first observed in Europe in the early 1990s, initially in the Balkans and later in Switzerland, Austria, Italy and France. It is said to cause damage worth 500 million euros annually, and this figure is bound to rise because the hungry insect increases its radius of activity by 80 kilometers every year.

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Affected corn plants

Germany is already “surrounded”, and experts believe that it is only a matter of time until the aggressive rootworm starts eating German corn too. The south-west of the country, in particular, is at risk; the corn rootworm has been observed in Alsace, and the neighboring region of Baden-Württemberg is already on the alert.

So interest in a product supplied by Bayer CropScience to protect corn plants is bound to be great. The product is a seed dressing, a compound used to treat seed before it is sown so that the active ingredient is released into the immediate surroundings of the young plant as it grows. This produces a protective zone of active ingredient around the plant which keeps pests at bay. This principle of action makes seed dressing an extremely efficient approach to crop protection. Protection is provided exactly where it is needed. In contrast, spraying is much more labor-intensive and less accurate.

The regulatory authorities in the USA approved the product from Bayer CropScience in 2003. The German authorities also recently gave expedited regulatory approval to enable farmers to respond rapidly to the threat of corn rootworm attack. Bayer CropScience deployed a mobile seed dressing unit to allow seed to be dressed quickly before it had to be planted.