Monochroa hornigi, the knotweed neb, is a moth of the family Gelechiidae.

It is found in most of Europe (except Ireland, Belgium, Luxembourg, Spain and most of the Balkan Peninsula),[1] European Russia, western and south-eastern Siberia, Transbaikalia, Korea and Japan (Hokkaido).

[3][4] Adults are on wing from July to August in one generation per year.

They mine the stems of their host plant and overwinter in a silken chamber.

This article on a moth of the genus Monochroa is a stub.