Directed research – Evaluation of different trunk injection devices and oxytetracycline formulations for efficacy against HLB, phytotoxicity, and feasibility

Directed research – Evaluation of different trunk injection devices and oxytetracycline formulations for efficacy against HLB, phytotoxicity, and feasibility

Report Date: 01/15/2024
Project: 22-001   Year: 2023
Category: Horticultural & Management
Author: Ute Albrecht
Sponsor: Citrus Research and Development Foundation

1. Please state project objectives and what work was done this quarter to address them: Objectives: 1) Test the efficacy of different injection devices, 2) Determine the most effective formulation of OTC, 3)    Determine the best month of injection and most appropriate OTC concentration based on tree size.    Trial 1: SW FL(Duda) – 8-year-old Valencia/Carrizo.    Trial 2: SW FL (Graves Bros) – 8-year-old Valencia/Kuharske.        Trial 3: East coast (Graves Bros) – 9-year-old Valencia/sour orange.    Trial 4: East coast (Graves Bros) – 4-year-old Valencia/x639.      Trial 5: Central ridge (King Ranch) – 4 year-old OLL8/x630  Fruit drop, disease ratings, and tree measurements were conducted. We are continuing with PCR/CLas analyses.Selected information from these trials was presented at the MISA conference in november at UCF. The grower collaborator for trial 1 has unfortunately stopped tree care after our year 2 injections, and trees have been declining rapidly. We have therefore terminated our evaluations in this trial.    2. Please state what work is anticipated for next quarter: Fruit drop assements will continue. Tree size measurements will be conducted. Leaf samples will be collected for PCR/CLas analysis. We are preparing for the harvest. Harvest dates will be coordinated with the grower collaborators.   3. Please state budget status (underspend or overspend, and why):Although our activities are on track, a large portion of funds intended to be used for OTC analysis at the USDA National Science Lab in Gastonia, NC, and for fruit quality analysis in 2024 remains unspent because the start/end date of the grant  coincides with the harves time. We have asked for a no cost extension to complete these research activities.     


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