Understanding and Manipulating the Interaction of Rootstocks and Constant Nutrition to Enhance the Establishment, Longevity and Profitability of Citrus Plantings in HLB-Endemic Areas

Understanding and Manipulating the Interaction of Rootstocks and Constant Nutrition to Enhance the Establishment, Longevity and Profitability of Citrus Plantings in HLB-Endemic Areas

Report Date: 05/06/2016
Project: 15-013   Year: 2016
Category: Plant Improvement
Author: Jude Grosser
Sponsor: Citrus Research and Development Foundation

Objective 1. (Greenhouse experiment): seedlings of the required rootstocks: x639, Swingle, WGFT+50-7, UFR-3 and UFR-15 were moved up to round citripots and moved into the HLB screening greenhouse. Liners are approaching stick-grafting size, and it should be possible to begin grafting in 2-3 months. Objective III: To evaluate the effect of complete, balanced and constant nutrition on HLB-affected mature trees (composition, delivery and economics). All the pretreatment data have been collected on trees, leaf and soil nutrient analysis were done to obtain a complete pretreatment tree assessment. First fertilizer applications were made at both the field locations and data was collected. All the data and photographs have been recorded for mid-year evaluation. Second round of applications are being made currently. All the micro-nutrient and foliar application products have been collected. Macro-nutrient applications will be made in August. Currently, all the data from pre-treatment and mid-year are being analyzed to confirm any differences among the treatments. Ojective 5. (funded by Orie Lee, using donated fertilizer products): Alligator Vernia/Rough Lemon Enhanced Nutrition Experiment � Treatments: 6 tree plots (randomized), 2 plots per treatment � treatments 2 times per year. The second treatment was applied May 30th, 2016. There was no further activity during this period. 1. Control � no extra nutrition 2. Harrells St. Helena mix (2lbs per tree) 3. Harrells St. Helena mix (2lbs.)+ 2x TigerSul manganese (90 gm) 4. Harrells St. Helena mix (2lbs.) + 2x Florikan polycoated sodium borate (32 gm) 5. Harrells St. Helena mix (2lbs.) + 2x TigerSul manganese (90 gm) + 2x FL sodium borate (32 gm) 6. 4x TigerSul manganese (180 gm) 7. 4x Florikan polycoated sodium borate (64 gm) 8. 4xTigerSul manganese (180 gm) + 4x Florikan polycoated sodium borate (64 gm) Baseline yield data was taken from each plot in January, 2016; pfd is severe and will impact the 2017 harvest. Donated micronutrient treatments were also applied at the Hughes Post Office block – where there were yield increases this past season, enhanced by specific treatments, especially those containing both boron and manganese. Trees look exceptional at present, and we expect to see a yield increase for the 2nd year in a row since we began the study.


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