I have been involved in herbicide bioassay research since 1983 studying the influence of biotic and physicochemical factors on herbicide efficacy and selectivity. Currently my main research interests are the influence of environmental factors on herbicide activity, joint action of herbicides, adjuvant effects on herbicide performance, chemical control of grass weeds in cereals, weed control in grass seed crops and herbicidal activity of natural compounds derived from plant species within the Cruciferaes.. Recently I have also become involved in ecotoxicologically related research studying the effects of sulfonylurea herbicides on non-target plants, phytotoxic effects of herbicides in precipitation and effects of pesticide mixtures on non-target organisms. Another recent research topic is allelopathy in wheat and barley and I am currently work package leader in the EU project FATEALLCHEM (2001-2004). I am also involved in projects in the Baltic countries and Poland and in a Danida financed IPM project in Eritrea.