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Diabrotica virgifera virgifera (Western Corn Rootworm)

Analysis of the economic, social and environmental impacts of options for the long-term EU strategy against Diabrotica virgifera virgifera (Western Corn Rootworm), a regulated harmful organism of maize

Diabrotica beetle feeding on maize silks (Picture Dr. Peter Baufeld/Julius-Kühn Institute)

Diabrotica virgifera virgifera, a serious threat to agriculture in the EU

Diabrotica virgifera virgifera (Western Corn Rootworm) is the most important insect pest of maize in North America, where it is endemic, and probably the most important worldwide. The insect has been listed in the EU as a regulated harmful organism with quarantine status. It was first detected in Europe in former Yugoslavia in 1992 and has since spread and become established in nine Member States. In the year 2008 incidental findings (isolated outbreaks) have been made in two additional Member States.

Diabrotica is a serious threat to agriculture in the EU because, as far as cultivation area is concerned, maize is one of the main EU crops. Both adults (beetles) and larvae attack maize, but the main economic losses are caused by the root damage inflicted by feeding larvae. Spread of the beetle is through natural migration, but there is also evidence for a passive spread of the insect through aircraft and probably by road and water transport (e.g. trucks and ships).

Damage to maize roots caused by Diabrotica larvae (four plants on the left; the four plants on the right have not been in contact with Diabrotica larvae) (Picture:Dr.Peter Baufeld/Julius-Kühn Institute).

Present Community provisions against Diabrotica

In the EU Diabrotica is a regulated harmful organism (the subspecies present in Europe, namely Diabrotica virgifera virgifera Le Conte, is listed in Council Directive 2000/29/EC, Annex I, Part A, Section II).

On 22 October 2003 the Commission Decision 2003/766/EC on “emergency measures to prevent the spread within the Community of Diabrotica virgifera Le Conte” was adopted. According to this Decision Member States have to conduct yearly official surveys for the presence of the insect in areas of their territory, where maize is grown. In case of an outbreak in an area which was previously known to be free from Diabrotica, defined measures have to be taken with the aim of eradication of the insect. In 2006 this decision was amended to introduce additional requirements for the containment of Diabrotica in the infested zones and their vicinity, to limit the spread of the insect from the infested zones into areas that are free of the insect. Technical guidance for the organisation of containment programmes is provided in Commission recommendation 2006/565/EC.

The present experience shows that the measures for the eradication of isolated outbreaks in place since 2003 are effective. For the official containment measures there is still limited information about their efficacy (they were applied for the first time in the 2007 maize growth season).

Diabrotica beetles feeding on maize silks (Picture: Dr. Peter Baufeld/Julius-Kühn Institute)

Need for a long-term strategy: Impact Assessment

Whilst Community emergency measures to control this pest are already in place, there has been increasing pressure from some Member States, and from farmer's organisations, to considerably review/amend the current rules in the light of the ongoing spread of the pest in the past years into new regions. However, in order to define a Community long-term strategy against Diabrotica, there is a need to carry out an evaluation of different policy options for their economic, environmental and social impact, and the resulting cost/benefit ratio. This would allow aligning the Community policy with the Better Regulation agenda. It would also seem sensible to consider such a strategy now because the range, and practicality, of options available for a long-term strategy will become restricted with time.

The European Commission has decided to carry out such an impact assessment for five previously identified policy options. An external contractor, the Food Chain Evaluation Consortium (FCEC), has been entrusted with the collection and collation of data on the potential economic, social and environmental impacts of these policy options, including on the status quo, on which information is needed to establish the baseline scenario. To this end, the contractor has consulted with all relevant stakeholders. The Terms of Reference prepared for this study provide a detailed description of the work to be carried out by FCEC and its deliverables. The study started in December 2008 and its final report was delivered at the start of June 2009.

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