Trachelus tabidus

Definition

A species of stem sawfly (Hymenoptera: Cephidae) whose larvae tunnel within the stems of grasses and cereal crops, causing internal galls or weakened culms that may lead to lodging or reduced yield. The species is among the larger and more conspicuous members of the family, with adults recognizable by their elongate, cylindrical bodies and reduced wing venation typical of Cephidae.

Etymology

Trachelus from Greek trachelos (neck), referring to the constricted 'neck' region between head and thorax; tabidus Latin for wasted or withered, possibly alluding to the shriveled appearance of infested stems or the pallid coloration of adults.

Example

In European cereal fields, Trachelus tabidus larvae mine the pith of wheat and barley stems, producing frass-filled galleries that compromise structural integrity; heavy infestations are distinguished from those of smaller Cephus species by the larger exit holes and more substantial larval chambers.

Related Terms

• Cephidae
• stem sawfly
• calamitous stem sawfly
• Cephus
• stem borer
• culm miner
• Hymenoptera

Usage Notes

Distinguished from the smaller and more economically significant wheat stem sawfly (Cephus cinctus in North America, Cephus pygmaeus in Europe) by body size and larval gallery dimensions; identification to species requires examination of adult genitalia or larval mandibular structure. The common name 'calamitous stem sawfly' has been applied historically but is not in universal use.