The purpose of this report is to examine the possibilities to decrease the number of insects and other pathogens in a crop of Pak choi (Brassica rapa), grown with different types of cover and living mulches. Included in the report is a study of literature where amongst others, a summary on the vegetable Pak choi and theories of living mulches and different kind of covers are to be found. To examine the amount of predators in the field, traps were used. During the autumn 2002 the tests were conducted in Alnarp. The Pak choi and the living mulches were planted/sawn at the same time, the different covers were also applied at this time. The total experiment was divided into six different treatments (plus control) of which three were with covers and three were with living mulches. Once a week the number of leaves, the height and damages were read on ten of the plants from each parcel.