Monochroa hornigi, the knotweed neb, is a moth of the family Gelechiidae. It was described by Otto Staudinger in 1883. It is found in most of Europe (except Ireland, Belgium, Luxembourg, Spain and most of the Balkan Peninsula),Fauna Europaea European Russia, western and south-eastern Siberia, Transbaikalia, Korea and Japan (Hokkaido).funet.fi
The wingspan is about 9–12 mm.Svenska fjärilarTrans. lepid. Soc. Japan 47 (4) Adults are on wing from July to August in one generation per year.LOT Moths and Butterflies
The larvae feed on Polygonum species, including Polygonum lapathifolium and Polygonum aviculare. They mine the stems of their host plant and overwinter in a silken chamber.Hants Moths
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