Spreading of western corn rootworm Diabrotica v. virgifera in Slovenia in the period 2003 - 2007

Abstract

The western corn rootworm, Diabrotica virgifera virgifera (Dvv), was found for the first time in Slovenia in 2003, in the eastern regions of Pomurje and Podravje along the border with Hungary and Croatia, and in the western region Goriška near the border with Italy. Between 2003 and 2007, its spreading in Slovenia was systematically monitored. To catch the pest we used pheromone and floral bait traps and yellow sticky traps. Computer analyses adopting plant protection geographical information systems (GIS) suggested that between 2003 and 2006 Dvv was spreading progressively from north-east towards the interior of the country by 24 km/year on the average while in 2007, due to favourable environmental conditions, the area of its spread increased by 70 km. The pattern of Dvv spreading indicates that the main transport routes such as roads, railway, Jože Pučnik Airport including some small scale airports with an increased inland traffic and larger resting places along the highways are, beside its natural spreading and growing of maize as monoculture, one of the major factors affecting its spread in Slovenia. In 2007, Dvv appeared earlier than in the previous years which resulted in a considerable difference as to the extent of spreading.