Sawflies are wasp-like insects. Adults are slender with a shiny black abdomen and yellow bands. Females have an ovipositor at the end of their abdomen, that allows them to saw into hollow-stemmed wheat to lay eggs. Larvae that develop inside wheat stems feed as they move to the base of the plant. Frass that is produced by feeding larvae forms a protective plug that provides shelter as they overwinter in stubble. The presence of the larvae causes bleaching of wheat heads, poor grain fill, stem lodging and shriveled kernals.