Dr.ir. W.A.H. Rossing
Wageningen Agricultural University
Dept. Theoretical Production Ecology
6700 AK Wageningen
Fax : +31.8370.84892
Growth and development of winter wheat during the post-anthesis phase is simulated as a function of injury by Sitobion avenae, the English grain aphid. The model applies to the time interval from flowering to ripeness which constitutes the main period of grain aphid immigration and development in winter wheat in the Netherlands. The crop model describes crop growth and development as a function of the prevailing weather and the available amount of soil nitrogen and consists of sink-source relations and distribution functions for carbohydrates and nitrogen. Injury by S.avenae affects crop growth both directly and indirectly. Direct effects on growth are due to aphid feeding. Indirect effects are caused by the aphid excretion product honeydew which affects leaf net carbon dioxide assimilation. Alternative hypotheses on the nature of the direct effects are formulated. Inputs to the model are average daily temperature, daily global radiation, the amount of nitrogen in the soil and the density on the aphid population. The major output is grain weight.
CAMASE (Concerted Action for the development and testing of quantitative methods for research on Agricultural Systems and the Environment).