Photo courtesy of Arnold Schumann, UF/IFAS
The U.S. Department of Agriculture National Institute of Food and Agriculture (USDA/NIFA) has invested more than $250 million to find a solution for HLB. One example of USDA NIFA-funded research is citrus under protective screen (CUPS).
University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) scientist Arnold Schumann and colleagues began testing CUPS at the Citrus Research and Education Center in 2014. Their CUPS system excluded HLB-spreading Asian citrus psyllids (ACP).
CUPS focuses on growing citrus for the fresh market. In addition to keeping out psyllids and HLB, CUPS creates a healthier environment for trees. “This results in higher growth rates, better fruit quality and higher yields while reducing the need for chemical pesticides, fertilizers and irrigation water,” Schumann said.
According to USDA NIFA, CUPS is the only successful technology that allows growers to profitably produce HLB-free citrus.
“The return on investment of this research project is high,” said Schumann. He estimated that Florida growers have invested about $75 million in CUPS, “allowing more than 1,200 acres of HLB-free citrus production by more than 200 growers.”
A SOLUTION FOR SUSTAINABILITY
Steven Callaham, chief executive officer of Florida’s Dundee Citrus Growers Association, was an early CUPS adopter. “This season, our four-year-old CUPS groves produced 800% more fruit per acre than our mature traditional groves,” said Callaham. “We are using 90% less land, water and fertilizer to produce each piece of fruit as compared to traditional growing methods.” He said CUPS provided Dundee with “a solution for not only surviving but a solution for thriving.”
Schumann said commercial CUPS growers have reported annual grapefruit yields four to five times higher than conventional HLB-impacted groves, starting as early as 2.5 years after planting.
Scientists also discovered that CUPS suppress citrus canker and provide protection from severe storms.
Jerry Mixon, owner of KLM Farms and 6M Farms in Florida, said growing fresh citrus in CUPS has sustained his company.
“Not only is our product great to look at but it is great tasting … Retailers are requesting CUPS-grown product,” said Mixon.
WHAT THE RESEARCH REVEALS
Top CUPS research findings include:
- ACP were sufficiently excluded from CUPS screen houses to restrict HLB incidence to less than 2% in 10 years.
- CUPS permits reasonable airflow, 80% visible light transmission and rainfall penetration.
- Researchers successfully grew red grapefruit at 1,361 trees/acre for 10 years in CUPS, with cumulative yields of 8,313 boxes per acre.
- Smaller arthropod citrus pests penetrate the CUPS screen and must be controlled with conventional pesticides.
- Many citrus varieties produce seedless fruit due to the absence of pollinators in CUPS, which increases their market value.
- Citrus tree growth rates in CUPS are about twice the rates in conventional HLB-free groves.
- Yields in CUPS are higher for some varieties like red grapefruit than they would be in conventional groves without HLB.
- CUPS fruit quality is exceptional with less external scarring from wind, leading to a high pack-out rate.
- Trees and fruit in CUPS are well protected from hurricanes, with negligible damage or fruit losses.
Source: USDA NIFA
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