College of Agriculture science and Natural Resource, Guilan University, Iran
The yield loss simulation (YLS) and the MACROS LIQ.CSM models were used to simulate the effect of stem borer damage at a detillering rate of 5, 15, 30, 60% at vegetative, panicle initiation and grain filing stages, on yield of rice cultivar?s Ratna. This stem borer damage during vegetative and panicle initiation stages was not simulated appropriately by both the models. Relatively MACROS simulated pest effects better than YLS at this stage. The predicted reduction in yield due to detillering at grain filling stage varied from 10.93-62.5 and 2.59-57.2% with the YLS and MACROS models, respectively in comparison to observed reduction of 4.8-56.1%. The simulated and observed pest effects on crop yield during grain filling stage were found to be comparable.