engleski

Western corn rootworm adult movement and possible egg laying in fields bordering maize fields

Western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte, larval damage in maize following soybean was observed in Croatia in 2003 along the edges and within soybean fields which bordered continuous maize fields in previous year. The only explanation was that WCR adults moved from the continuous maize to the neighboring soybean fields to lay eggs. This study was designed to measure how far WCR adults will enter into neighboring fields to lay eggs. The WCR adult population was monitored in continuous maize fields in 2003 and 2005 by using Pherocon® ; AM yellow sticky traps in the middle and on the borders of the maize field and at different distances and directions into neighboring fields planted by wheat and soybean. Larval presence and root damage ratings (Iowa State University 1-6 scale) were recorded at different locations within the maize field in 2004 and 2006. Approximately the same concentration of WCR adults was recorded along the edges of the maize fields as recorded in the centers of those fields. A significant number of WCR adults was recorded up to a distance of 50 m into neighboring fields. Regression analysis showed medium negative correlation between distance from previous maize field and root damage in the following year (r = -0.39 ; r2 = 0.144 ; ). Findings indicate that WCR egg lying can reach approximately 20 m into fields neighboring maize fields and that significant root damage caused by WCR larvae in first-year maize following soybean and wheat can happen up to a distance of 20 m into those fields. Most farmers’ fields in Croatia are up to approximately 50 m wide. Since an edge effect for WCR egg laying can reach approximately 20 m into fields neighboring maize fields, our research results indicate that it is possible to see WCR larval damage in rotated fields without those WCR’ s being the variant form.

adult movement; first-year maize; root damage; soybean; western corn rootworm; wheat

nije evidentirano