Incidence of Heterodera avenae, on wheat, Triticum durum, under Tunisian field conditions

摘要

The effect of initial densities of Heterodera avenae on the yield of wheat, Triticum durum cv. Karim, and on nematode population dynamics has been studied in six experimental field sites located in different bioclimatic zones, from and to sub-humid. Increasing H. avenae densities significantly reduced the different yield components and grain yield loss varied from 26 to 96%. The relationship between nematode densities and wheat yield is according to Seinhorst models with damage threshold densities of the order of one egg or larva/g soil. Nematode multiplication rates are negatively correlated with initial densities but they remained above unity in all of our trials. The H. avenae populations showed large differences in multiplication rates and densities in the sod, depending on the experimental site. These differences may result from agro-climatic characteristics of the regions and/or the action of biological antagonists.