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: 07/14/2023
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: Located in SW Florida (Duda) – 8-year-old Valencia/Carrizo trees.  HLB ratings were conducted. Wounds from year 1 injections were assessed. Year-2 April injections were completed. Leaves were collected for CLas analysis prior to injections. Trial 2: Located in SW Florida (Graves Bros) – 8-year-old Valencia/Kuharske trees. Trees were harvested and fruit quality analysis was completed. HLB ratings were conducted. Wounds from year 1 injections were assessed.  Year-2 injections were completed. Leaves were collected for CLas analysis prior to injections.     Trial 3: Located on the east coast (Graves Bros) – 9 year-old Valencia/sour orange trees. Trees were harvested and fruit quality analysis was completed. HLB ratings were conducted. Wounds from year 1 injections were assessed. Year-2 injections were completed. Leaves were collected for CLas analysis prior to injections. Trial 4: Located on the east coast (Graves Bros) – 4-year-old Valencia/x639 trees.   Year-2 May injections were completed. HLB ratings were conducted. Wounds from year 1 injections were assessed. Leaves were collected for CLas analysis prior to injections.  Trial 5: Located on the central ridge (King Ranch) – 4-year-old OLL-8/x639 trees.    Year-2 May injections were completed. HLB ratings were conducted. Wounds from year 1 injections were assessed. Leaves were collected for CLas analysis prior to injections. Presentations including research findings from this project:- Citrus Growers Institute, Avon Park- Citrus Grower meeting, Tavares- USDA PPQ CHRP meeting, Gainesville- Citrus Annual Conference, Bonita Springs   2. Please state what work is anticipated for next quarter:A subset of trees in trials 1, 4, and 5 will be injected in September. Leaves will be collected for nutrient analysis.  3. Please state budget status (underspend or overspend, and why):The budget is slightly underspent as we are still waiting for the USDA National Science Lab in Gastonia, NC to complete the OTC residue analysis, which will be around $24,000.     


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