European corn borer (Ostrinia nubilalis Hbn) population fluctuation at Zemun Polje between 1986 and 2005

The European corn borer (ECB) (Ostrinia nubilalis Hbn) is one of the most important pests of maize in Serbia. Therefore, it has been and continues to be an attractive subject of research. The flight of ECB adults has been monitored by light traps at the Maize Research Institute in Zemun Polje, Serbia since 1966. Significant qualitative changes in the ECB voltinism occurred during the last three decades of the 20th century. ECB used to be extremely univoltine with 80-90% moths of the first generation, but lately it has become predominately bivoltine. During these 20 years of monitoring, a total of 52,450 specimens were captured (32,382 females and 20,068 males) and their population varied between 351 moths per year recorded in 2001 and 8,347 recorded in 1987. Ratio between the first and the second generation has been changed so that the larger number is the second generation: on the average 1:5.94 (first: second generation), and ranged between 1:0.34 recorded in 2004 and 1: 21.6 recorded in 1987