Quick scouting of eggs of western corn rootworm (Diabrotica virgifera virgifera LeConte, 1868) from soil

Main method to control the American Corn Rootworm is crop rotation (Camprag et. al., 1994) but we don't know how to determine the possible number of larvae under fall so we cannot use autumn cereals to change the row of cultivated plants. The pest spends almost 10 months in soil in egg and larval state (Chiang, 1973). There are two methods for scouting Diabrotica eggs and larval instars from soil over the winter. One of the two most important methods is holding soil samples on fixed temperature (Fromm et al., 1999). This method takes more than one and a half month but its result is highly reliable. The conventional egg-washing technique takes fewer days to count the number of Diabrotica eggs in soil but it has lower effectiveness than the other one because the eggs in a sample cannot be counted correctly. Our results show that the effectiveness of egg washing with high concentrated salty water (NaCl) is high and the method is quick enough to help planning the crop rotation even under the autumn period (Takács et al., 2004).