The past century has seen the citrus industry grow from the fresh fruit packinghouses of early citrus pioneers to today's billion-dollar industry for processed juice and fresh fruit. At the University of Florida's (UF) Citrus Research and Education Center (CREC) in Lake Alfred, scientists and engineers have made several key scientific discoveries and technological advancements that have been pivotal to the industry's development.
CREC was established in 1917 after a group of Polk County citrus growers raised nearly $14,000 to purchase some land for a research station. Originally, only a few UF scientists were assigned to the Lake Alfred site, then called the Citrus Experiment Station. Today, CREC employs 250 people and is also home to the scientific research staff of the Florida Department of Citrus. It is the largest facility in the world devoted to a single commodity, citrus.
Here’s a look at some key accomplishments by CREC’s personnel over the past century, from the early 1900’s to present day, and the mark that their work has made on history - citrus and scientific.
CREC researchers developed current technology for making frozen concentrate orange juice. The process was patented in 1948 by E.L. Moore, L.G. MacDowell, and C.D. Atkins of the Florida Citrus Commission, now known as the Florida Department of Citrus. Frozen orange juice concentrate was an instant hit with the public and Florida orange juice became one of the world’s favorite beverages.
The Nutritional Needs of Citrus Trees
In the early 1900’s, little was known about plant nutrition. CREC scientists determined that citrus trees need several minor elements, including copper, zinc, manganese and iron. CREC, in conjunction with the USDA, developed fertilizer recommendations for citrus and provided growers with some of the most comprehensive nutritional information available for any crop at that time. These pivotal advances in plant nutrition lead to more efficient fertilizer use and substantial increases in fruit production.
Yellow Spot, a widespread problem in the first half of the century, caused citrus trees to lose leaves and eventually die. In the 1950’s, I. Stewart and C.D. Leonard determined that it was due to a deficiency of the mineral, molybdenum, and that it could be corrected by application of sodium molybdenum.
First Mechanical Hedging Machine
In the 1950's, citrus tree pruning studies led to the development of the first mechanical hedging machine built at CREC. Now, mechanical hedging is a standard practice in Florida groves. Research on production practices has enabled growers to manage and maintain the high-density plantings common in Florida groves today.
In the 1950’s and 1960’s, some growers lost up to 70 percent of their crops because of “spreading decline.” CREC scientists R.F. Suit and E.P. DuCharme discovered that the cause of “spreading decline” was the burrowing nematode. Following this discovery, a team of scientists developed a control program for the burrowing nematode that many believe saved the industry.
In the 1960’s, CREC scientists discovered that a fungus, Mycosphaerella citri, was the cause of a disease called greasy spot. Further work led to an understanding of the life cycle of the fungus and the development of control measures.
The use of petroleum oil sprays for pest control was developed by CREC scientists in the 1960’s. Today, oil sprays are an important component of integrated pest management programs for scales, aphids and other insects.
Advancements in Citrus Juice Processing
UF and the FDOC scientists and engineers have worked with the citrus industry on improvements in juice processing technology, orange and grapefruit juice quality and flavor, food safety, studies on citrus’ nutritional benefits, and research on citrus by-products. For the past 50 years, scientific researchers have presented research updates at Citrus Processor’s Day, an annual conference held at CREC.
Florida Juice Quality
CREC-FDOC researchers have played a big role in developing juice quality standards for Florida orange and grapefruit juice. Analytical methods have been developed to detect the adulteration of juices and their country of origin. These methods help ensure that Florida citrus products are always top-notch quality. FDOC scientists test over a thousand juice samples every year to make sure that they meet Florida standards.
In 1973, Alternaria brown spot disease appeared on Dancy tangerines in Florida. Within a couple of years, growers were suffering substantial yield losses. CREC scientists identified the cause of the disease as the fungus, Alternaria citri, and by 1976, recommendations for control of this disease were published.
Fifty years ago, citrus irrigation was uncommon. Studies initiated in the 1950’s demonstrated that proper irrigation could increase yield. Further research focused on water conservation and led to the development of microsprinkler systems, considered to be the most economical and efficient system today.
Freeze Protection Methods
Early methods to protect citrus trees and fruit from freezing weather utilized heaters or wind machines. In the 1980’s, CREC and other UF researchers demonstrated that microsprinkler irrigation was effective for freeze protection. Today, microsprinkler irrigation is the most commonly used form of citrus freeze protection in Florida.
UF and FDOC researchers continue to work closely with Florida’s fresh fruit industry, making advancements in decay control, degreening, storage, handling, packaging and packinghouse technology. CREC scientists publish a Packinghouse Newsletter and host an Annual Packinghouse Day, a meeting where scientists and industry personnel share information about the latest topics in fresh fruit packing.
CREC faculty have published numerous widely recognized books and publications, including the Florida Spray Guide and the Florida Citrus Pest Management Guide. CREC scientists also publish Extension fact sheets and technical bulletins for both homeowners and citrus growers, many of which are available free to the public. Faculty members also are on editorial boards of scientific journals.
At CREC, scientists are studying ways to manage the Diaprepes root weevil (Diaprepes abbreviatus). A serious threat to Florida groves today, CREC’s multi-disciplinary research effort focuses on studying the biology of this insect and devising integrated pest management programs.
CREC researchers have been instrumental in developing new and improved citrus varieties with traits such as disease resistance and superior flavor. At CREC, scientists have made breakthroughs in techniques to produce novel citrus hybrids and regenerate seedlings in tissue culture. These techniques hold promise for making further improvements in citrus varieties.
Environmentally Safe Production
CREC scientists work on ways to minimize the leaching of herbicides, fertilizers and other chemicals into groundwater and to develop environmentally safe production practices.
Molecular Biology of Citrus Tristeza Virus
CREC scientists are working to uncover the molecular secrets of the citrus tristeza virus, the cause of some of citrus’ worst diseases, in efforts to develop effective management strategies. Working with other laboratories, a team of scientists have decoded the sequence of the virus’ genetic material - no small task, for the citrus tristeza virus is the largest plant virus known.
UF and CREC engineers and scientists are adapting satellite and computer technology to help growers manage their citrus groves. Called “precision agriculture,” it involves the use of global positioning system (GPS) satellites, computers and other high-tech equipment to analyze trees in a grove for disease and pest problems, soil deficiencies and other problems that may otherwise go undetected.