Management of tree health and huanglongbing disease pressure using advanced Zn formulations

Management of tree health and huanglongbing disease pressure using advanced Zn formulations

Report Date: 07/18/2023
Project: 22-002   Year: 2023
Category: Other
Author: Swadeshmukul Santra
Sponsor: Citrus Research and Development Foundation

1. Please state project objectives and what work was done this quarter to address them:
Santra research team was focused on evaluating CRDF provided OTC tank-mix samples during the reporting period.

Below is the summary of our research findings.
Field OTC tank-mix samples showed the following physico-chemical characteristics.
a. the pH of the sample does not change over time. It was measured to be 1.0 (not 2.0)
b. both OTC samples ages with time as confirmed by the change of color from light yellow to brown.
c. stability of the OTC samples were compromised over time as confirmed by the DLS, OD600 and SEM results. Particle formation followed by the particle aggregation was observed for all samples over time.
d. OTC characteristic peak located around d value 7 completely disappeared after 3 days. This suggests that there is no more OTC left in solution. It is possible OTC is only present in the aggregated particles.
e. Antimicrobial activities of OTC samples do not change over time as long as the products are homogenized (particles are re-suspended; based on lab studies).

If particles are not mobilized within the trunk after injection, it is unlikely that we will see the full potential of OTC treatment for managing HLB.

Additionally, we are in the process of analyzing Year 1 tree health trail data on grapefruit which will be included in the next report.

2. Please state what work is anticipated for next year:

Complete Hamlin trials as they were affected by hurricane Ian.
Second year of data in Valencia to confirm the effect we are seeing in yield increase.
Finish IAA analysis in both Hamlin and Valencia.
Elucidate if oxidative stress is alleviated by these Zn formulations.
Closer assessment of quality.

3. Please state budget status (underspend or overspend, and why):
Current status: About 100% completion of Year 1 objectives.
Overall: About 40% completion of the proposed objectives for the duration 3 years.


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