9. Effect of planting date on density dynamics and damage rate of Oscinella frit (l.) and Oscinella pusilla (Meigen) (Diptera: Chloropidae) in winter wheat

The effect of sowing date on abundance of Oscinella frit and Oscinella pusilla and damage degree of larvae on winter wheat shoots were evaluated at the Plant Protection Institute in Kostinbrod from 2004 to 2009. Flight of Oscinella frit and Oscinella pusilla, and damages caused by their larvae were found in the wheat fields sown in the last decade of September and the first decades of October 2004, 2008 and 2009. Fields, sown during the second and third decades of October were not infested by frit flies.