Assesment of population level of the invazive species Nezara viridula in diferent crops from South West of Romania

Green bug (Nezara viridula) is a pest recently reported in our country (respectively in 2010, Timisoara). It is known to be present in different areas and different plants. It has a different food regime from one area to another. Therefore, in this paper we proposed an approach to knowledge the population size in Caras Severin County, from the South-West of Romania. The research covered all areas of the county and were carried out during the years 2015-2016. Observations were conducted in eight cities (Resita, Caransebes, Oravita, Anina, Bocsa, Moldova Noua, Herculane and Otelu Rosu). In each locality was determined several areas and observation points (ZO-5/OP-5) representing the previously established crops. Readings were performed monthly beginning in June and ending with October. The plants under the macroscopic observations were part of both agricultural area and the horticultural. The results of the monitoring and measurement of specimens found have shown an abundance of species in areas Bocsa, Oravita and Herculane. Maximum values recorded in observation points reached 80-100 individuals. Few individuals were made in Resita and Caransebes (8-12 individuals). Most specimens were observed during August-September. In all areas monitored prevailed larvae and nymphs. As regards the type of crop/plant, it can be noted that the higher presence was indicated on corn, beans, tomatoes, and berries. Bug has not been reported in towns: Anina, Moldova Noua and Otelu Rosu. The presence of the species was noted especially in the lowlands of the county and less or no in higher areas. Bug current state in the Caras-Severin County are of installation and ongoing monitoring