This report covers the period of March 1, 2020 – May 31, 2020. During this period, M.S. student Chad Vosburg made a visit to the USDA United States Horticultural Research Laboratory (USHRL) in Fort Pierce, FL, to help initiate a Asian citrus psyllid (ACP) transmission experiment for HLB resistance testing of the FT-scFv transgenic ‘Duncan’ grapefruit lines produced for this project. In addition, he continued work on an HLB graft transmission test and analysis of field trees at the USHRL Picos farm in Fort Pierce. Continuing work collaborating with personnel at USHRL (Greg McCollum, Ed Stover, Earl Taylor) has produced some initial preliminary patterns in the HLB tests. Two lines were tested by ACP-mediated transmission, along with controls. As of this writing, all the trees except for three trees of one FT-scFv line were exhibiting some level of HLB symptoms at 3 months into the experiment. This indicates that the HLB transmission was highly successful. In addition, ACP nymphs were observed on all the trees, indicating that the HLB-carrying psyllids had actively colonized and reproduced on the test plants, which is conducive to HLB transmission. Symptom severity differed between the transgenic lines and the ‘Duncan’ control trees, but has not yet been quantified. We hope to obtain quantitative symptom measurements in the next reporting cycle. The trees planted outdoors at the Picos farm were tested by PCR for presence of ‘Candidatus Liberibacter asiaticus’ (CLas) and all found to be negative at about 6 months after plating, including control trees. The same two lines used in the field test were also grafted to rough lemon heavily infected with CLas, along with control grafts. Buds of the two transgenic lines grew vigorously and showed no or limited HLB symtpoms so far, while control buds showed severe stunting or failed to grow out. We are cautiously optimistic about that result, but the experiment will need to be repeated. The experiment is ongoing and bud graft growth, symptoms, and CLas titers will be measured. The PI also applied for and received the necessary permits to bring additional FT-scFv transgenic lines to Pennsylvania for analysis. We hope to be able to do a transfer in the next reporting period. It should be noted that the Covid-19 shutdowns of Penn State and USHRL in late March, 2020, has affected work progress. In mid June, work has cautiously resumed at Penn State. However, this situation has caused some delay of experimentation and limits access to plants at USHRL. We anticipate that it will very likely be necessary to request a no-cost extension to be able to complete the project objectives.