TYLCV infection influences water balance in plants exposed to drought stress. Several physiological parameters were constantly fixated for HW, HD, VW, and VD tomatoes grown in an iCore greenhouse during 14 days of drought application (dd). HW, not infected (healthy) and watered; HD, not infected and subjected to drought; VW, infected and watered; VD, infected and subjected to drought. (a) Efficiency of daily transpiration. Daily transpiration was calculated according to follow equation: difference of plant mass (g) between plant weight, fixated in morning and evening. Mean ± SD continuous daily whole‐plant transpiration during the entire experimental period, values with different letters are significantly different (Tukey HSD, p < 0.05, Tukey post hoc was done only at certain time points: 1, 5, 9, and 13 dd). (b) Normalized transpiration rate (E) and canopy stomatal conductance (GS). Mean ± SD of midday transpiration rate normalized to calculated plant weight (E) and whole‐canopy stomatal conductance (GS) during the entire experimental period between 11:00 and 13:00; values with different letters are significantly different (Tukey HSD, p < 0.05, Tukey post hoc was done only at certain time points: 1, 5, 9, and 13 dd). (c) Physiological drought point (Θcrit) and water use efficiency (WUE). Θcrit was identified as midday transpiration rate versus the soil water content (SWCcrit) of tomatoes grown in water‐withholding conditions (HD and VD). WUE is identified as the ratio between the gain of daily weight and the daily transpiration. Mean ± SD of WUE calculated automatically by SPAC‐analytics software; values with same letter are not significantly different (p < 0.05, Student's t test). (d) Calculated plant weight (CPW). CPW was determined as the sum of the initial plant weight (fixated before start of iCore growth) with the cumulative transpiration multiplied by WUE. Mean ± SD of CPW for the entire experimental period; values with different letters are significantly different (Tukey HSD, p < 0.05, Tukey post hoc was done only for 14 dd)