Defra

The Western corn rootworm, Diabrotica virgifera virgifera, was first confirmed on five farms in the vicinity of London Heathrow and Gatwick airports in 2003. Surveys in 2004 and 2005 confirmed the continuing presence of the beetle in the outbreak area but the more extensive national surveys did not identify any new outbreaks.

The 2006 survey comprised

1) A national survey to monitor maize-growing areas throughout the UK

2) Increased monitoring of maize fields in an extended buffer zone within 50km of outbreak farms

3) Continued intensive monitoring in the Focus Zone (1km around outbreak farms) and Safety Zone (1-6 km).

Results

• No beetles were confirmed in the national survey

• The increase in the radius of the buffer zone survey to 50km did not result in any new finds outside the Focus and Safety Zones demarcated in 2005

• The number of adult beetles captured in the existing outbreak area was lower than in previous years. A total of 27 beetles were found on traps in 9 maize fields at 6 farms

• The first beetles to be caught were trapped on the 27th July, earlier than in previous years

• Several Beetles were caught in fields planted with treated seed. This may indicate that either the beetles have flown in from surrounding crops or that the seed treatments have not been effective under UK conditions.

Recommended Control Measures

Crop rotation is the most effective means of control. Maize growers, particularly in the south of England, are advised to rotate maize with alternative crops wherever possible. This helps to break the life cycle of the pest. Larval stages hatching in spring from eggs laid in the soil will starve if no maize roots are available to feed on.

Avoid maize or rotate game cover crops as this provides a reservoir of the pest and poses a risk to maize crops in the surrounding area. Use non-maize seed mixes wherever possible or rotate maize grown for game cover.

Further details on the Western corn rootworm, including recognition, life-cycle, pest status and action being taken in the UK, can be found here* (pdf). A Pest Risk Analysis (PRA) (pdf) is also available.

*Large file - you can also right-click link and save to your PC.  Click right if you need free pdf software