IPSIM Acyrthosyphon pisum infestation in a pea/wheat mixture at flowering

The hierarchical structure contains 13 attributes (9 input attributes, and 4 aggregated). The effects of weather are decomposed according to two seasons: spring and winter. Winter weather is only described with temperatures. Spring weather attributes are temperature, rainfall, and wind speed. Landscape input attributes are represented by proportions of semi natural areas, leguminous crops and organic fields. The last two input attributes are related with crop management: efficacy of chemical treatments (insecticides) and the crop mixture features in terms of pea density (pea sole crop, pea density lower, equal to, or higher than recommendations). The aggregated attributes at the second level (in black bold in Figure 1) represent the overall effect of weather and landscape composition on Acyrthosyphon pisum level of infestation.

The attribute weights are presented in Figure 2 according to the method described by Bohanec et al (2013). For instance, the global weights (second column in Figure 2) at the first level, “Weather”, 40%; “Cropping practices”, 42%; and “% of leguminous crops in the landscape”, 18% sum up to 100% for the aggregative attribute “Landscape composition”.