Modeling the development of a target site resistant Apera spica-venti (L.) P. Beauv. population – A comparison of model output and field data

Abstract

A population dynamic model was combined with a genetic model and embedded into a cellular automaton. The model was evaluated with data from two three year field trials which were conducted on commercial fields in Lower Saxony and Saxony where target-site resistance to acetolactate synthase (ALS) inhibitors was detected in Apera spica-venti. The cropping system consisted of continuous winter wheat in the trial period. On four plots different herbicide strategies were tested. These were continuous application of a soil herbicide, alternation between ALS inhibitor and soil herbicide, continuous use of an ALS inhibitor and two applications per growing season with different mode of actions (MoA). In the beginning of the trial soil samples were taken to estimate the number of viable seeds in the seed bank. This data was used to produce seed distribution maps by interpolating the estimated seed data over the field. These seed maps were then used as the initial seed bank in the model and simulations over three years were executed with the assumption of herbicide use as conducted in the field trial. A comparison of the model output with the field data showed very good analogies in the weed density. Also the development of resistance was reproduced well. The model can now be used to assess herbicide management strategies concerning the development of herbicide resistance for A. spica-venti.

Keywords

• ALS resistance
• genetical model
• population dynamic model
• loose silky bent