See new citrus nutrient recommendations that were presented at the Florida Grower Citrus Show and the latest in citrus research.
The Florida Grower Citrus Show was this month, and a Citrus Industry article shared the details of the latest in citrus research that was presented, including new citrus nutrient recommendations. Seminar speakers also shared information on symbiont strategy, using drones, plant growth regulators, lebbeck mealybugs, and scions and rootstocks. See the details below.
New Citrus Nutrient Recommendations and More
The following information from the Florida Grower Citrus Show, including new citrus nutrient recommendations, was shared in the article:
New Nutrient Recommendations. “Kelly Morgan, UF/IFAS professor, shared recent updates to citrus nutrient guidelines. The recommendations for foliar manganese and zinc have increased from 3–5 pounds per acre per year to 15 pounds per acre per year. For soil applications, the amount has increased from 7–10 pounds to 25 pounds. Currently, UF/IFAS has no set recommendations for calcium and magnesium other than pH maintenance.”
Symbiont Strategy. “Michelle Heck, research molecular biologist with the U.S. Department of Agriculture (USDA) Agricultural Research Service (ARS) spoke about her research on symbionts to treat HLB. Symbionts, which can be used in both established groves and new plantings, produce and deliver therapeutic molecules directly into citrus trees to improve their health. Trees are not altered in any way; modification is limited to the symbiont. This strategy is working in the greenhouse, and field trial planning is underway. The technique is a continuous whole plant treatment without repeated spraying.”
Work With Drones. “John Chater, UF/IFAS assistant professor, summarized his work using drones to measure citrus tree health. Drones were flown over 1,337 acres of citrus, including 91 sites composed of scion and rootstock trials, commercial groves and germplasm repositories. The goals of the study included providing an inventory of what is planted and a list of top performers. While data is still being analyzed, among the shining stars for sweet oranges are N13-32 on UFR-4 rootstock and the OLL varieties.”
New Nutrient Recommendations. “Kelly Morgan, UF/IFAS professor, shared recent updates to citrus nutrient guidelines. The recommendations for foliar manganese and zinc have increased from 3–5 pounds per acre per year to 15 pounds per acre per year. For soil applications, the amount has increased from 7–10 pounds to 25 pounds. Currently, UF/IFAS has no set recommendations for calcium and magnesium other than pH maintenance.”
PGR Potential. “There were several take-home messages from Tripti Vashisth’s presentation on plant growth regulators (PGRs) to improve the health of HLB-affected trees. The UF/IFAS associate professor stressed that more leaves mean more potential for fruit production, and timely PGR application is critical. Gibberellic acid can improve yield efficiency in Hamlin and Valencia, while 2,4-D is showing promise in reducing fruit drop. Cytokinin, a growth hormone, may also be helpful in holding fruit on trees.”
Lebbeck Mealybug Identification. “In 2020, lebbeck mealybugs became a problem in Florida citrus. The pest can be difficult to distinguish from other mealybugs, but Muhammed Ahmed, USDA ARS research entomologist, discussed an easy, five-minute method for identifying the pest. He tested 57 species of mealybugs and only lebbeck mealybug turns green when dipped in potassium. This applies to all life stages of the pest.”
Scions and Rootstocks. “Kim Bowman, USDA ARS research geneticist, detailed two new SuperSour rootstocks with exceptional performance. US-1688 and US-1709 (tentatively named US SuperSour #4 and US SuperSour #5, respectively) are expected to be commercially released later this year. Both have demonstrated superior multi-year performance with Valencia and Hamlin scions on Flatwoods and Ridge sites. These rootstocks produced better yield, canopy health and total soluble solids than Swingle, Sour Orange and other rootstocks…”
Griffin Fertilizer is committed to helping both growers and ranchers make sound agronomic and economic decisions in order to maximize the health of their grove and pasture. As a full-service custom dry & liquid fertilizer blender and crop protection product distributor, we will continue our mission to further advance Florida agriculture. For questions or concerns about your farm or pasture, contact us and one of our team will be in touch.
