To obtain the precise calculation method for the peak energy density and energy evolution properties of rocks subjected to uniaxial compression (UC) before the post-peak stage, particularly at sigma >= 0.9 sigma(c) (sigma denotes stress and sigma(c) is the peak strength), extensive UC and uniaxial graded cyclical loading-unloading (GCLU) tests were performed on four rock types. In the GCLU tests, four unloading stress levels were designated when sigma = 0.9 sigma(c). The variations in the elastic energy density (u(e)), dissipative energy density (u(d)), and energy storage efficiency (C) for the four rock types under GCLU tests were analyzed. Based on the variation of u(e) when sigma >= 0.9 sigma(c), a method for calculating the peak energy density was proposed. The energy evolution in rock under UC condition before the post-peak stage was examined. The relationship between C-0.9 (C at sigma >= 0.9 sigma(c)) and mechanical behavior of rocks was explored, and the damage evolution of rock was analyzed in view of energy. Compared with that of the three existing methods, the accuracy of the calculation method of peak energy density proposed in this study is higher. These findings could provide a theoretical foundation for more accurately revealing the failure behavior of rock from an energy perspective. (c) 2025 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/ 4.0/).

The root-knot nematode Meloidogyne javanica is a significant pathogen that causes substantial yield losses in tomato plants. Moroccan farmers generally lack knowledge regarding the density of this pathogen, which can trigger visible and localised symptoms. Additionally, regional studies that establish damage thresholds for this issue are scarce. This study investigated the damage threshold of M. javanica on tomato plants using nine initial population densities (Pi) of second-stage juveniles (J2s): 0, 0.5, 1, 2, 4, 8, 16, 32 and 64 J2s (g dry soil)-1. Aboveground growth (plant height and fresh and dry shoot weight) and belowground growth (root length and diameter) were assessed after 90 days. The plant growth parameters were significantly reduced at higher inoculum densities. The Seinhorst model fitting revealed the highest minimum relative yield (m) for shoot fresh weight (m = 0.761 +/- 0.012) and the lowest for root diameter (m = 0.509 +/- 0.026). The tolerance limit (T) varied, with the highest shoot dry weight (T = 1.657 +/- 0.329 J2s (g soil)-1) and lowest root diameter (T = 0.095 +/- 0.019 J2s (g soil)-1). The production of eggs by M. javanica increased significantly with increasing initial population density, rising from 211 +/- 64 eggs (g roots)-1 at 0.5 J2s (g soil)-1 to 3735 +/- 380 eggs (g roots)-1 at 64 J2s (g soil)-1, representing a 17.7-fold increase. Tomato plants exhibited the maximum galling index at lower nematode densities. Symptoms began at densities as low as 0.095 J2 (g soil)-1, with severity increasing with nematode density. Given the severe damage caused at low densities, Moroccan farmers must adopt early detection and effective management strategies.