Corn rootworm

Diabrotica - the nightmare of all corn producers

In America it is called the "billion dollar bug". And it seems that the western corn rootworm is trying to live up to this reputation on the old continent. Brought in from the USA in the early 1990s, the beetle has already caused billions of dollars’ worth of damage in European corn crops. Until 2014, the spread was controlled with insecticides from the neonicotinoid group. After the ban on these bee-killing pesticides, the problem has intensified dramatically.

The most important figures on corn rootworm misery.

  • Corn is the economically most important arable crop worldwide
  • Around 7 million hectares of European corn acreage are already infested by the corn rootworm (corresponding to approx. 36% of the total corn area)
  • 20-80% loss of yield = € 360-1.440/ha

Exponential propagation aggravates the problem

  • The females are ready to mate shortly after hatching. Their eggs do not have to be fertilized immediately. Sperm can be kept in the spermatheca for a long time and are then continuously used to fertilize the eggs.
  • Within a few weeks, a single female lays an average of 400 eggs. 6-11% of these survive.
  • A single beetle therefore produces about 40 beetles in the following year. This exponential growth illustrates how extensively and rapidly the pest spreads without containment measures

How Diabrotica v.v. damages the corn plant

The greatest damage is caused by the larvae of the corn rootworm, which eat the roots. The resulting severely restricted absorption of nutrients and water reduces their stability. As a result, a corn plant attacked by the pest cannot develop as usual (goose-neck symptom) or falls over. The beetles cause feeding damage to the plumes (pollen feeding), to the grain threads, to the cobs (grain feeding) and to the leaves (strip feeding). Feeding on the grain threads impairs fertilization, whereby the plant hardly develops any corn grains on the cob. The loss of yield on the infested areas amounts to between 20 and 80% and therefore runs into billions if not controlled.

Crop rotation only partially solves the problem

In many places, crop rotation is recommended as a means of controlling the pest. This is a very sensible measure, which is also prescribed by law in heavily affected regions. However, it does not solve the problem in the long term because the corn rootworm also lays its eggs in other crops such as pumpkin, soy, or wheat. The beetle can also feed on cereal grasses and it has been observed that some larvae can even hibernate for more than two years.

Securing the future with biotechnology

Combating invasive species poses completely new challenges for developers of crop protection products. And failure is not an option. That is why we are working all the harder to provide agriculture with effective methods that make ecological and economic sense. Together, sustainable agriculture can succeed!

Questions about the corn rootworm?

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This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No #880432