M. BORIANI, E. GERVASINI
Lombardy Region, Phytosanitary Service, P.zza IV Novembre 5, 20124 Milano, Italy

Maize is the most important field crop in Lombardy (Northern Italy) where over 350.000 hectares are cultivated. In 2000, the maize pest western corn rootworm (WCR), Diabrotica virgifera virgifera Le Conte (Coleoptera: Chrysomelidae), was detected for the first time near the Milan Malpensa Airport (Varese). Three specimens were collected on two farms using pheromone traps. As a result, two distinct areas of infestation were identified and within these maize cultivation was prohibited in 2001.

An extensive monitoring campaign was carried out in 2001 and over 300 PAL pheromone traps were placed in the 11 provinces of the region. WCR was found at different population levels in 8 provinces covering over 100.000 hectares of maize. In Como and Varese provinces, the highest numbers of WCR adults/trap were observed when compared to the other provinces. However, damage caused by larvae and adults was not noted. Preliminary evidence suggests that the area of Malpensa Airport is not the real origin of WCR spreading and that a different hypothesis on the matter is advanced here.

The results of adult monitoring and population levels observed are also reported.