University of Illinois

No. 10/May 30, 1997

Note on Cereal Leaf Beetles

Robert Bellm, Crop Systems Educator at the Edwardsville Extension Center, observed a significant number of cereal leaf beetles in a wheat field in the Jersey/Greene counties area during the latter part of the week of May 19. He found as many as three to four larvae per flag leaf near the edge of the field, but the density decreased dramatically to less than 0.5 per flag leaf toward the interior of the field. The economic threshold is three or more eggs and/or larvae per stem. Because cereal leaf beetle larvae are not very mobile, a spot treatment could be effective in this field. This situation emphasizes the importance of scouting the entire field and recognizing that thresholds usually are based on average numbers of insects for the entire field. Consequently, single samples, especially samples taken near the edges of fields, often do not represent the average population density of a pest within a field.

More information about cereal leaf beetles was printed in issue No. 5 (April 25, 1997) of this Bulletin.

Kevin Steffey,Extension Entomology, (217)333-6652