Nysius is a difficult genus and most of the seven UK species are very difficult to identify without reference to a specimen.
N. huttoni is best distinguished by the long hairs that cover the pronotum and forewings, but this can be difficult to see and ideally requires a specimen under the microscope.
A very recent arrival in Britain from the near continent, but actually native to New Zealand, where it is known as the 'Wheat Bug' and can be a serious pest of crops in hot summers. No crop damage has so far been reported in Britain and the species has only been found in coastal East Anglia and in Kent. Further information.