Quantification of bioagressors induced yield gap for grain crops in France
Analyzing yield losses of crops is instrumental in sustaining high productivity. Here, we develop statistical modelling of yield losses by French department based on weather, soil and epidemiological data for 13 diseases and 12 insect pests of grain crops over 8 years. Those environmental factors explain up to 90% of yield variations (wheat). Weather and soil quality are first order determinants as manifested both by direct assessment and by strongly correlated yields of even taxonomically very different crops. Bioagressors are important second order determinants: losses of 5 qx/ha (~7%) on wheat and 2 qx/ha (~15%) on winter oilseed rape. Across models based on conceptually different achievable yields, only Septoria tritici and Sitobion avenae on wheat, and Ceutorhynchus picitarsis and Ceutorhynchus assimilis on winter oilseed rape are consistently and significantly detrimental to yield. Those bioagressors seem not fully controlled which is compatible with empirical observations in the non academical litterature.