1. Please state project objectives and what work was done this quarter to address them: Main objective: To determine the large-scale efficacy of trunk injection of OTC on citrus tree health, fruit quality, and yield in existing rootstock trials in three different commercial growing environments. Sub-objectives: a) test the efficacy of OTC injection in the rootstock trunk compared to injection into the scion, and b) determine whether OTC injection increases/restores root densities and if there are interactions with the rootstock. Three trials were evaluated (rootstocks UFR-3 and UFR-16 were not included due to poor performance): Trial 1 (near Babson Park, Polk County): 6 rootstocks (US-812, US-942, US-897, UFR-2, UFR-4, Carrizo). Trial 2 (near Venus, Highlands County): 5 rootstocks (US-812, US-942, UFR-2, UFR-4, sour orange). Trial 3 (near Felda, Hendry County): 5 rootstocks (US-812, US-942, UFR-2, UFR-4, Swingle). The experimental design for OTC injections was established in all trials and trees were flagged accordingly. All trials were injected by a commercial crew guided by our team. One set of trees within each rootstock plot was injected in the scion. Another set was injected into the rootstock, and another set remained non-injected to serve as a control. The rate was 1.1 g of OTC (Rectify) and was delivered in a volume of 100 ml (11,000 ppm) using the FlexInject injectors.During injection, a subset of trees from 3 selected rootstocks in each trial were monitored to compare the speed of uptake between rootstock injections and scion injections. We found that the uptake rate was mostly affected by the time of day and the environmental conditions on the day of injection. The uptake rate varied from less than 20 minutes to several hours.Leaves from selected subsets of trees were collected 3 days, 1 week, and 1 month after injection to determine CLas titers and OTC concentrations. 2. Please state what work is anticipated for next quarter: We will continue with leaf collections for CLas and OTC analysis. We will also conduct root density measurements. 3. Please state budget status (underspend or overspend, and why):The budget is as expected.