In this study, the effect of full (IR100), 50% (IR50), 75% (IR75) and 125% (IR125) irrigation levels on population development of the carmine spider mite (CSM) as well as on yield and some pomological properties of ‘Fortuna’ strawberry cultivar grown in high tunnels were evaluated in two consecutive growing seasons (2016–2017 and 2017–2018). The numbers of CSM were significantly lower on strawberry leaves which were irrigated by IR50 and IR75 in both growing seasons. Full (IR100) and highest (IR125) irrigation levels were the most favorable for the development of CSM populations. On the other hand, in the CSM thriving period (2017), the fruit weight was generally high in the plots with the highest irrigation (IR125) level. Although there was no interaction with the CSM population, fruit acidity (%) increased in the IR100 and IR125 irrigation levels, possibly due to stress in plants, when CSM population was highest (in March). In the absence of CSM, fruit acidity was significantly high in the plots where water stress was experienced. While no significant interaction was found between the pomological characters and the CSM population, the mites affected the yield significantly in that plants were more productive under IR 75 even when there was a CSM population. This study suggests that the application of IR75 level in Fortuna strawberry is related to lower CSM population growth and significantly higher yields.