Eucalyptus globulus Labill. plantations in the Iberian Peninsula occupy nearly 1.5 Million ha but Millions of Euros are being lost due to growth decreases caused by insect defoliation. The existence of tools capable of estimating the impact defoliation has on growth is crucial for helping forest managers to anticipate damage and implement the most suitable and sustainable management strategies to fight pests. A recent study presented the 3-PG.d simulator (for more details see: https://doi.org/10.1016/j.foreco.2020.118495), a forest management decision-support tool designed to allow simulating the growth of eucalypt plantations considering different defoliation scenarios. This user-friendly tool allows users to define the intensities of each attack and the number of years during which the attack occurs. The tool is being further improved to allow forest managers to perform economic analysis that will enable assessing the trade-offs between growth-losses caused by defoliation and the application of insecticides.