The influence of weather and geographical conditions on flight dynamics of WCR adults

Since the appearance of western corn rootworm (Diabrotica virgifera virgifera Le Conte) (Coleoptera: Chrysometidae) in Romania, many researchers have been made, in more or less success. In this study we try to clarify the ecology of the species in order to predict its evolution and its potential area of distribution. In Romania, this species was signalled for the first time in 1996, in western part of country neighbouring with Hungary. This region is an important area for maize production for seed and silage. Together, the climatic conditions, altitude and their influence on species behaviour and distribution have become more apparent. Their habitat and survival strategies are strongly dependent on local weather patents and altitude. In order to investigate the potential impact of weather and altitude on pest populations, a clear understanding of the nature and characterization of pest is required. In general, most pest species are influenced by warm, rainfall and altitude. Taking into consideration our data from the years 2008 and 2009, we can emphasize a very serious influence of air temperature, rainfall and altitude on WCR flight dynamics in adults. Dry and warm conditions generally lead to increasing of insects' number. Our data shown positive correlations between air temperature (daily mean) and adults number captured on pheromone traps (daily mean), but the there are limits from which these become negative. The same trend was recorded in previous research period (2004-2006). The rainfall is an important factor that influences adults' dynamics in maize fields. Excessive rainfall leads to adults' number decreasing. Our daily observations showed a decreasing number of beetles while rainfall increases. Regarding the altitude, we observed a decreasing number of WCR adults at once the attitude increase. For capture of adults we used pheromone traps, in 3 replications (T1, T2 and T3) at difference altitude where maize was grown. Significant relationship of WCR flight dynamic with weather and geographical conditions were found. Activities were carried out under the PN-II-ID-PCE-2007-1/RO project.