J. KISS, B. KHOSBAYAR, J. KOMÁROMI
Szent István University, Department of Plant Protection, H-2100 Gödöllö, Hungary, J. IGRC-BARCIC, R. DOBRINCIC
University of Zagreb, Agricultural Faculty. Svetosimunska 25. Zagreb, Croatia
I. SIVCEV
Inst. for Plant Protection and Env. T. Drajzera 9. P.O.B. 936. 11001Beograd, FR. Yugoslavia
C.R. EDWARDS
Purdue University, Dept. of Ent., 1158 Smith Hall, West Lafayette, IN 47907-1158, USA
I. HATALA-ZSELLÉR
Plant Health and Soil Cons. Station, H-6801 Hódmez?vásárhely, P.O. Box 99, Hungary

The focus of this study was to evaluate how WCR may adapt to European crops grown in rotation with corn. A three-year crop rotation trial was established in 2000 in Szeged in Southern Hungary (EU-5 project). This system was followed within the framework of the FAO WCR Network in Croatia and Federal Republic of Yugoslavia in 2001. This allowed for comparisons to be made among three different regions in Europe (Szeged in Hungary; Tovarnik in Croatia; and Dobanovci, near Belgrade in FRY). The crops rotated with corn were corn (therefore, continuous corn), sunflower, soybean, and a cereal (winter wheat, oat or spring barley). Corn was grown on the trial fields in previous years. The study field was divided into two sections. One section consisted of corn (field A), while the other consisted of 6 replications each of a cereal, sunflower, soybean, and corn (field B). The year after, these two sections were rotated so that the rotated crops in one section were followed by corn and the corn section by the rotated crops. The presence of WCR was assessed and quantified by using Pherocon AM traps and emergence cages (3 each per plot) from mid June to mid September. In addition, corn roots were dug from each plot and rated for WCR larval damage and soil samples were taken from each plot to determine WCR egg populations. Weed cover data were recorded 2 times during the growing season.

In Hungary, results for 2000 showed small catches of WCR adults on Pherocon AM traps and no WCR adults in emergence cages in crops other then corn. The WCR population increased in the area in 2001. For 2001, an increased number of WCR adults were caught on Pherocon AM traps in sunflower, soybean, and cereal (latter harvested) plots, in addition to significant numbers caught on the traps in the corn plots. Some WCR adults were found in emergence cages in corn after soybean and cereal. WCR population in the region was low in FRY, while higher in Croatia in 2001. In FRY, WCR adult occurrence on Pherocon AM traps was low in corn and soybean. In sunflower and oat, there were no WCR adults caught. In Croatia, the numbers of beetles caught on Pherocon AM traps in the corn field were high (similar to those of 2001 in Hungary). Numerous WCR adults were trapped in crops other then corn (again similar to Hungary in 2001). Emergence cages caught some WCR adults in corn (field A) and no adults in crop rotation strips (field B) in FRY. The number of beetles caught in emergence cages in Croatia in corn field A averaged 34.75 beetles, while in corn field B the average was 5.8 beetles per 3 cages during the growing season. Some WCR adults were trapped in emergence cages in soybean and sunflower, but no beetles were found in the barley. The sex ratio for all WCR adults, root damage ratings, egg washing results, etc., will be presented at the meeting.