Abstract: Western corn rootworm (WCR, Diabrotica virgifera virgifera Le Conte) are serious economic pest of maize (Zea mais L) in U.S. and an important invasive insect for European maize cultures. The actual situation In Romania showed a continuous extension of the WCR from west part to east part of country. In 1996 the insect was signaled for the first time in Nadlac locality from Arad County. In 1997 the Diabrotica virgifera virgifera Le Conte adults was very frequent along the border with Yugoslavia, but it also registered in the area near to Hungary. In 1998 the pests has begin to spread especially in Timis County. After, 2000 the Diabrotica population heaves increased strongly year by year until now, occupying news zones from Romania.  For counties from west part of country, the invasive species are become very damaging, so we tried by means this paper to develop some partial maps of spreading in accordance with environmental factors.  Following the statistically data it can be observed positive correlations between daily no of adults and environmental factor- relative humidity of air). The spreading maps were realized taking in consideration the number of individuals/location. We establish groups of frequency (low, middle and high level) marked with different colors. Groups: low level 600-5000 individuals/locality (600-1000 ad., 1100-1500 ad., 1600-2000 ad., 2100-2500 ad., 2600-3000), (3100-3500, 3600-4000, 4100 – 4500, 4600-5000,  6100 – 10500 6100-6500 ad., 6500-6550 ad.) and high level (10500 – 11000 ad., 11500-12000 ad., 14500 – 15000 ad., 18500-19000 ad. , 21100 – 21500ad.).  The maps of spreading shown a high level for Timis and Arad counties; middle level for Bihor county and low level for Caras Severin, Cluj Satu Mare and Salaj counties. We acknowledge a technical support of all farmers from different localities who have provided us the maize fields. The Ministery Education financed this work within the framework of PN-II-ID-PCE-2007-1/RO project.

WCR; Diabrotica virgifera virgifera Le Conte; adult; spreading; maps; maize

Presentation: oral