For those who have lived in Central Florida for the past few decades, the changes have been beyond belief.
Because of arctic freezes, growth and urban development, along with shortages of farm labor and a new pestilence known as citrus greening, citrus trees are no longer as abundant as they once were, and grove owners fight an uphill battle to maintain what they have.
“It’s no longer a major crop,” DeLand grove owner Richard Marshall said.
Marshall’s spread of fruit trees is southwest of DeLand, and not far from the St. Johns River.
“I only have 7 acres in grove,” he said, adding he has shifted some of his land into producing ferns and foliage for the floral industry.
Of the 7 acres of citrus trees — which number approximately 1,000 — Marshall says two-thirds bear oranges and one-third bear grapefruit.
The oranges he harvests are Hamlins and navels, and the grapefruit are the red variety.
“The grove is early-maturing fresh fruit,” Marshall said. “It’s sold as fresh fruit and not for concentrate or juice. Early maturing means November, December and January. Some of it is susceptible to greening.”
One fruit formerly plentiful in the winter and now scarce is the satsuma. Marshall has none these days.
“They all died,” he said.
The ravages prompted Marshall to end gift shipments of citrus fruit a few years ago.
Indeed, signs of citrus greening are showing up in Marshall’s grove, despite his best efforts to head off the disease. Citrus greening originated in China and spread to the United States about 20 years ago, according to experts.
A small fly known as a psyllid spreads the disease.
“The psyllid bites the leaf. It only takes one bite, and the bacteria grow,” Marshall said. “It dries up the roots and the leaves.”
Citrus greening may be likened to malaria in human beings. Once the tree becomes infected, it stays infected, and there is — as of now — no way to reverse or kill the disease before it kills the tree.
The tree usually dies slowly, as the outermost branches and limbs succumb to drying and withering, and the disease moves into bigger limbs toward the trunk. A large, healthy, well-producing tree may die in about five years. The fruit, meanwhile, may not fully ripen and may be less tasty or even inedible.
“The roots can no longer feed the leaves, and the leaves can no longer feed the roots,” Marshall said.
Unlike other citrus growers, Marshall prefers to avoid man-made pesticides and chemicals in his grove.
“Since there is no cure for the bacteria, a lot of growers spend a lot of time on spraying. I have chosen not to use sprays. They kill so many of the insects, the gnats, the flies and other things,” he said.
One natural countermeasure Marshall is using is a special parasitic wasp, which may be the psyllid’s only natural enemy. The insect, he said, is not to be confused with the aggressive swarming insects with painful stings.
“They’re tiny. They are wasps in name only. They are harmless to humans. They are noninvasive,” he said.
Because Marshall’s is one of the few surviving groves in Volusia County, the University of Florida’s Institute of Food and Agricultural Sciences (IFAS) is monitoring his citrus production and his use of the wasps.
“I fill out the survey, because this grove is pesticide-free. Several researchers are keeping an eye on it to see if the wasps have helped,” he said.
He receives a small box of wasps every two weeks.
“They must constantly be replaced,” Marshall added.
Marshall himself is a UF alumnus, Class of 1966, with a degree in engineering.
In addition to the special wasps, Marshall said some hope for a more effective defense against citrus greening may come from scientists who have isolated the tree-killing bacteria carried by the psyllids. That is a vital first step in determining how to counter the microorganisms responsible for the disease.
Hoping for a breakthrough that will preserve some of the agricultural heritage of Volusia County and the state, Marshall is not giving up on his own citrus production — although many other landowners have already done so.
He is replanting some of the diseased, dying and dead trees in his grove. But he’s uncertain how long production will continue.
“I’m 80 years old now. It’s a risky business. There is risk involved,” he said.