The impact of water stress on tripartite plant-pathogen-vector interactions represents a complex and predominantly underexplored area within the study of plant-insect relationships. Tomato yellow ring orthotospovirus (TYRV) is an emerging threat to tomato crops, causing significant yield losses. Frankliniella occidentalis, commonly referred to as western flower thrips (WFT), is a key pest of tomato crops and is the primary vector of TYRV. In this study, we investigated how water stress (WS) and TYRV infection influence the demographic parameters of WFT. These results indicated that viral infection significantly enhanced adult longevity, oviposition period, and fecundity. Nonetheless, the demographic analysis revealed that severe WS conditions adversely affected the effects of TYRV on thrips populations, leading to a decline in overall fitness. Although the highest values of r and λ were recorded under moderate WS conditions, the observed differences in r and λ values were not statistically significant. R0 experienced a negative impact from WS, indicating potential long-term consequences for population sustainability. Overall, TYRV infection partially mitigated the detrimental effects of WS on WFT biological traits, specifically under moderate stress conditions, indicating a complex interplay between host stress and viral infection. This study provides insights into the ecological dynamics of F. occidentalis under climate change scenarios, emphasizing the importance of understanding host-virus interactions in pest management strategies. These findings suggest that integrated pest management approaches should consider both abiotic stressors and viral infections to control thrips populations and mitigate crop damage effectively.

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