EWRS Working Group:

Crop Weed interactions


At the time of establishment of the Working Group "Crop-weed interactions" the main research related to this topic  focused on descriptive models to support rational decision-making on the use of herbicides to minimize damaging effects of weeds on crops. Later on, a more  ecological approach was pursued (Mortensen 2002). The  WG proceeds to track current trends in ecological  research and the management of weeds and develops new directions of research relevant to weed management in general and crop-weed interactions in particular.

Currently, the focus of the WG is on the mechanisms of competitive interactions between crops and weeds and  how these can be modified by management measures (Workshop 2017) and on factors which play a major role in the outcome of such interactions (Verwijst et al. 2018).

In 2022 the WG has merged with the former WG 'Parasitic Weeds'.

Competitive Interactions

A quantitative reduction in crop yield due to weeds is  ascribed to the ability of weeds to compete for light, water  and nutrients, at the expense of the crop. The relative  competitive ability of weed species is determined by two groups of interacting factors. The first one consists of  weed species characteristics, such as propagation and dispersal features and other life cycle characteristics, and  potential crop growth rate. The second one is made up by the environment, which to a large extent is determined by the cropping system and its management. This implies that improvements in weed control in agriculture need to be based on both weed (and crop) ecology (Mortenson et al. 2002), and on the influence of the particular crop and management system on the population dynamics of weeds (Barberi 2001).