The objectives of this study are to identify optimal pH range for root function and minimize root turnover on HLB-affected rootstocks and how uneven pH levels in the root zone (e.g. irrigated vs. row middle portions of root system) affect the overall health of the tree. This is being done in a split root system in the greenhouse where pH of different parts of the root system can be controlled an maintained. The following progress reported is based on a October 31st report date. The 2nd experiment testing different irrigation pH’s on each half of the split root system (to mimic irrigated and non-irrigated root zones) was transplanted to rhizotrons and is underway. It is expected to complete in February or March of 2021. We continue to analyze data from the first experiment and trees for a 2nd repetition of the first experiment will be purchased when NCE funds are available. As we continue analyzing the results we have found that HLB infected roots appear to have caused an increase in pH in the leachate from the pH 5.5 irrigated US942 compared to the healthy and uninfected roots of the inoculated plant. This is based on limited data due to COVID restrictions limiting sampling in April and May. If repeated this suggests that the soil-root interaction is dramatically changed in CLas infected roots, whether due to leakage or alterations in citrus root physiology.