December 28, 2016 | Vanessa Caceres

Citrus greening has wreaked havoc on the citrus business in Florida, a state long associated with its prolific orange production.

Citrus greening—also called Huanglongbing or yellow dragon disease—first hit Florida in 2005, says Lukasz Stelinski, PhD, associate professor of entomology and nematology, University of Florida Citrus Research and Education Center in Lake Alfred. However, the disease had previously affected crops in Brazil and Asia.

The Asian citrus psyllid—a bug that can fit on your fingertip—is the vector that spreads the bacteria causing citrus greening, Stelinski says. The sugars in affected trees cannot be transported effectively, and that leads to a decline in the plant’s health. “The tree begins to look sick. It drops fruit and it declines progressively,” Stelinski says.

Ultimately, the fruit remains green because it never ripens. Fruit affected by citrus greening cannot be used or sold.

The bacterial disease has affected all groves in Florida in some way, Stelinski says. In fact, that’s led to a massive economic hit.

The citrus business in Florida has a $10 billion-plus economic impact and supports about 60,000 jobs, the Florida Department of Agriculture and Consumer Services reports.

The orange crop forecast for the 2016/2017 growing season from the U.S. Department of Agriculture (USDA) is 70% lower than that from 20 years ago and 14% lower than the 81.5 million boxes produced in the 2015/2016 season. Peak production was 244 million boxes in the 1997/1998 season according to USDA.

The vast majority of oranges grown in Florida are used for orange juice, so the juice business has seen a similar decline.

Citrus greening has caused about $4 billion in economic damage and has eliminated some 8,000 jobs, according to a study done four years ago by the University of Florida

Citrus greening has also changed the way that citrus farming is done. “Integrated pest management was a cornerstone before, but that has been abandoned because pesticides have been used heavily” to combat the Asian citrus psyllid, Stelinski says.

There still is no permanent solution to fight citrus greening, but researchers and farmers are trying various methods, Stelinski says. These include the mitigation of abandoned citrus, which can be sources for the spread of disease; enhanced nutritional management for the trees; antimicrobial management; the growing of citrus under protective screening; and the breeding of citrus that is tolerant of the disease, Stelinski says. Growers have worked closely with researchers at the University of Florida to identify potential solutions that fight citrus greening.

Although not all potential fixes for citrus greening have worked, they’ve provided insight into how to better control the Asian citrus psyllid. The breeding of tolerant trees that don’t succumb to disease appears to be a potential longer term solution, Stelinski says.

Citrus growers in adjacent areas work in a coordinated fashion to try these fixes. “They don’t want to treat one area and leave the other area untreated,” which would leave the area still vulnerable for disease, he says.

Despite the gloom and doom, there is a sense of hope that the industry will survive the challenge, Stelinski says. Growers are optimistic that potential solutions will help fight citrus greening so they can continue farming and pass on the business to the next generation.

A number of growers are venturing into crops as diverse as peaches, blueberries, olives, hops, pomegranates, and bamboo to offset the citrus losses.

Tim Brown of Brown’s Grove in Sarasota is a long-time citrus grower who now grows more vegetables, but who also has added more citrus to his mix. “People think I’m crazy,” he says. Even though that move is greeted with skepticism, he believes the growing options available to treat citrus greening will help and that his younger trees will help keep disease away.