How Florida Citrus is Growing Through Paradigm Shift

How Florida Citrus is Growing Through Paradigm Shift

Hand-pruned California citrus grove

Here’s an example of the extent to which young mandarin trees are hand-pruned in California’s central San Joaquin Valley. Expensive as this practice may be, it regularly offers a 200% to 300% return on investment through improved tree health and superior fruit quality.
Photo courtesy of Future Fruit

It may be safely argued that there has been no more overused phrase in the business and agribusiness worlds over the past 25 years than “paradigm shift.” Though this may be true, we could exhaust valuable hours contemplating a better way to describe the reality facing Florida nurseries and growers and come up empty.

Today, we have new rootstocks, new scions, new operational nursery practices, new grove architecture, transitional nutrition schemes, citrus under protective screen (CUPS) systems, an aging grower base, and a deadly and devastating disease (HLB) under “yesterday’s model.” Nothing is being done the old way. Nurseries and growers — who still have the resources and fortitude — are experimenting at breakneck pace in hopes of finding that next incremental improvement that will contribute to their immediate survival and hopeful viable future.


Nursery Challenges
Nurseries that invested in newly available plant material soon discovered each variety seems to have special needs. This sometimes involves adjusting substrate, nutrition, and pruning practices; and recognizing variety compatibility with rootstocks, budwood production, and perhaps even budding methods. Trial-and-error approaches are time-consuming and costly but are currently the only path forward. Today’s nurseries are more innovative and observant than ever before.

Adjustments are being made to soil and water pH, nutrient packages, irrigation methods, and anything else that will improve the health and productivity of trees going to the field. In some cases, early tree production suffers until more information becomes available and the nursery develops a production plan for each variety. Production of liners from tissue culture (TC) or seed of newly available rootstocks are not immune to this problem and, in fact, may present an equally daunting challenge. All of this has led to higher nursery production costs resulting in higher tree costs.

Sugar Belle citrus fertilizer program growth comparison

Image courtesy of Jude Grosser, UF/IFAS

Grower Challenges
Growers are equally challenged to select the right rootstock/scion combination in the right location with the right production management program. We often refer to spoon feeding new trees, but it all boils down to identifying nutritional needs (root and leaf analysis) and constant adjustments to meet the needs of new varieties.

Field and CUPS growers have reported redesigns of irrigation and fertigation systems so that treatment of blocks can be managed independently to accommodate the unique needs of varying tree ages and varietal selection. Schemes that help rapidly establish canopy and structure may (though perhaps should not) postpone fruit set or degrade internal and external quality.

Fresh fruit growers traveling abroad are returning with a feeling that we are but babes in the woods when it comes to manual pruning and practices to induce bloom and stick fruit; minimizing alternate bearing; and improving fruit quality. Most of these practices are expensive and outside of our cultural norms. They also sound like bad news to growers who are already tight-roping between red and black ink. However, expensive as these practices may be, they regularly offer a 200% to 300% return on investment through improved tree health and superior fruit quality.

Beyond Basic Science
What good does it do to use this space to echo our frustrations? Because a problem defined is a problem half solved. We have tremendous talent and experience at our disposal at UF/IFAS and USDA-ARS. Citrus Research and Development Foundation is hard at work to identify the projects that will bring the most immediate practical value and relief to the Florida grower.

We simply must look beyond basic science to produce the tools needed by the nurseries and growers who are working to restore our short citrus supply. Projects must be funded in these other areas if nurseries are to produce and maintain healthy trees for the field. Growers and nurseries need production manuals for each new scion and rootstock variety. Granted, new varietal options are becoming available quicker than research teams can generate this information, but we must ensure the research is ongoing to maximize nursery and field production practices.

Nurseries have traditionally operated somewhat outside the inner circle of the citrus industry, operationally having more in common with the ornamental industry than citrus production. However, while nurseries serve as the bridge between new variety development and field production, they have never been more central to the common cause. What nurseries are learning about the new material may be of use to those developing field production plans.

We must work to ensure that as nurseries identify their research needs and priorities, they are addressed with the same enthusiasm as those projects that target the pathogen and vector. Florida should supplement basic research with an adequate commitment to applied research. As a wise man once said, we need a solution I can hook to the tractor. Florida’s rapidly expanding variety portfolio requires applied horticultural research to fully realize its potential. Whether the focus is pound solids per acre or superior whole fruit quality for the domestic and international markets, it is a massive paradigm shift.