GETLAUS01—the latest version of a model for simulating aphid population dynamics in dependence on antagonists in wheat

Abstract

GETLAUS is a discrete and deterministic model for simulating cereal aphid population dynamics in dependence on antagonists. The complexity of the model was gradually increased, and the features for assessing biological and ecological relationships were expanded. The latest version, GETLAUS01, contains submodels for wheat, cereal aphids ( Sitobion avenae, Rhopalosiphum padi, Metopolophium dirhodum), coccinellids ( Coccinella 7-punctata, Propylea 14-punctata) and syrphids, model units for chrysopids, carabids, staphylinids and spiders, and algorithms for parasitization, moulding, pesticide effects on aphids and antagonists and yield losses. Simulations are started by entering aphid and antagonist population densities (individuals per m 2) measured at BBCH 69 (end of wheat flowering). The programme then describes their subsequent abundance development as influenced by biotic interactions, temperature, rainfall and wheat development. This paper gives a detailed account of the current version of the simulation model. The model was used to study and demonstrate tri-trophic interactions, particularly aphid population dynamics influenced by antagonists under different natural and man-made conditions, but not to predict future aphid infestation. Findings based on simulation results obtained using field data will be presented and limitations in calculating predator occurrence and their effects will be discussed. The GETLAUS simulation model has proved to be a suitable tool for obtaining information on the mechanisms and dimensions of natural control.