## 4 Discussion
Nevertheless, these findings suggest that to predict the plant state correctly when attacked by spider mites, signal samples of several minutes up to half an hour are most effective. The spider mites have needle-shaped mouthparts that allow them to feed by penetrating the plant tissue, which causes plant damage that is perceived locally. However, depending on the severity of the damage, the presence of spider mites induce long-distance electrical signaling through the entire plant [29; 30; 31]. The reduction in the features space only slightly affected the classification performance. However, with the decrease in the number of features, both the model's complexity and its tendency to overfit also decreased. Another advantage of using fewer features is the reduction in the computational time required to build the model and to apply it on newly acquired data from other plants, conforming with the needs of the crop producers. The isolation between the plants used for the training from those used in the testing increases the objectivity of the performance assessment and strengthens the evaluation of each model. Therefore, the built classifiers are expected to perform similarly for new recordings coming from other tomato plants. Further studies should include an extended cohort of tomato plants to confirm the presented findings, and their reproducibility should be investigated for other growth seasons and other crops as well. Another improvement would include modeling of several stages of stress, for example, initial, middle and strong stress, which would allow greater precision in detecting plant status and, potentially, a detection of a spider mite infestation before the appearance of visual symptoms. Another valuable contribution would be to understand more profoundly the changes in the plant occurring at cellular level. Among early signaling events that occur in response to biotic stress, electrical variations can be highlighted; it is crucial for induction of appropriate physiological modifications such as genetic regulation, metabolism adaptation, hormone synthesis or defense mechanisms [31; 32]. Moreover, ion fluxes, apoplastic pHmodification, ROS generation and calcium variations are responsible for electrical signaling [33; 34]. Hence, investigations on how transporters contribute to slow and long-term bioelectrical potential variations would help in modeling. For instance, as in the studies of the current literature based on ancestral alga _Chara_ demonstrating the presence of a characteristic red noise triggered by a salinity stress and mediated through H\({}^{+}\)/OH\({}^{-}\) channels [26; 35; 36], such investigation would allow to discern the transporters causing alterations in the tomato electrophysiological signal in the presence of spider mites. By expending the knowledge of plant electrical responses in that context, the choice of signal features to use for an automated detection of changes in plant state could be further refined, which would also potentially lead to an accurate classification even for an early stage of infestation. Overall, the presented findings in this study represent a starting point of building new possibilities for more optimal preventive and curative crop protection practices.