Huanglongbing (HLB) causes a steady decline in tree health. Part of this decline includes root dieback which limits their capacity to take up water. For this reason, affected trees tend to be more susceptible to drought stress. This raises a significant concern during the dry season (Oct-May) when trees are largely dependent on supplemental irrigation for water. Unfortunately, most growers continue using irrigation schedules that were optimized for healthy trees. We hypothesized that irrigating more frequently, but in smaller doses would provide more opportunities for uptake and improve water relations in HLB-affected trees. The control treatment received the standard practice of irrigating every other day for 2 hours (12 gal/hr). The experimental treatment received water every day, 3 times a day, for 20 minutes (12 gal/hr). The two treatments received the same amount of water over the course of a week, but the experimental treatment received water more often. Treatments were initiated prior to flowering in January 2022 and were continued for two years. Tree water status improved in the experimental trees as reflected in higher mid-day leaf water potentials than in the control. This suggests the experimental regime was better able to maintain tree water status than the conventional method. In the second year, flowering was more synchronized in the experimental treatment. The control treatment saw two peaks in bud production with the latter one being consistent with a drought stress-induced flowering event. The experimental trees also saw an increase in fruit set in both years. Trees receiving the experimental and control treatments dropped a similar proportion of their crop load during June Drop and preharvest fruit drop in year 1 and 2. Finally, the experimental treatment resulted in significantly higher yields on average than the control in both year 1 and year 2 (72% and 200%, respectively). Altogether, more frequent irrigation improved tree productivity.
