Population dynamics and population control of Galium aparine L.

The population biology of Galium aparine L. needs to be better understood, in order to be able to rationalize decisions about the short- and long-term control of this weed species for different cropping practices.

A population dynamics model was developed to simulate the basic processes of the life cycle of G. aparine as influenced by environmental conditions. The effect of temperature, light, moisture, nitrate supply and soil structure on germination and emergence and on growth and seed production were investigated. Data were integrated in a model simulating field emergence and an ecophysiological model on crop-weed competition. The information was used to evaluate the effects of crop rotations, control levels, cultural measures and timing and choice of soil cultivation practices on the population dynamics of G.aparine. The ecophysiological model of competition between G. aparine and sugar beet was extended to predict reductions in crop yield reduction and increases or decreases in the weed population on the basis of the actual situation in the field. The variation caused by weather conditions appeared to be small.

The results of simulations demonstrate the possibilities of reducing herbicide use to control G.aparine in both the short and long term, by adapting crop rotation and cropping practice, increasing mechanical control in cereals and not controlling lateemerging G. aparine plants in sugar beet.