Agri Leader

The citrus sentinel

Photos

CHRISTY SWIFT
Published: May 16, 2012

Polk County citrus agent Chris Oswalt has been in citrus a long time. He still remembers irrigating his dad's groves "old school," that is, by dragging aluminum irrigation pipes down a couple of rows, watering, then dragging them to the next set, one or two rows at a time.

"It was character-building," the 53-year-old joked.

But it's hard to laugh these days, when Florida's citrus industry is being devastated by citrus greening.

"They're all over the place," said Oswalt of the psyllid insect, the vector for Huanglongbing, also called HLB, yellow dragon disease or citrus greening. Greening causes yellowing of new plant growth, mottled leaves and small, misshapen, bitter fruit. It was first seen in China in the 1800s.

Oswalt first set eyes on the disease on a single tree in Brazil, where he attended a training session on greening shortly after it was discovered in Florida.

Later, he began to witness the effects over larger areas of groves, first in Hillsborough County and then in Polk, where he got his first call reporting the disease in the summer of 2007. Within a week, greening was being found from one end of Polk County to the other.

Oswalt has been with the Polk County Extension Service office for 10 years. He got his undergraduate degree in citrus production management from the University of Florida, followed by a master's in horticulture/fruit crops, also from UF.

Right out of graduate school, Oswalt joined the Brevard County Extension Service as a citrus agent in 1988. He spent four years there before leaving to work in private industry as a production manager of a citrus and tomato operation in south Hillsborough County. He returned to extension service work in Polk in 2001.

It was not too difficult to jump back into the public sector even after being out as long as he was.

"The principles of plant science don't change much," he said. However, he had to catch up on the latest scientific developments.

In extension, agents are in touch with researchers at UF and across the state, and so have access to information right away whenever there is a breakthrough. The information gets to growers more slowly, Oswalt said.

But whereas extension agents provide education to growers, it's the growers who must decide whether the recommendations are viable and whether to implement them.

When a solution is embraced and delivers as expected, it's a high-five moment for extension agents like Oswalt.

"It's gratifying when they implement some of those things and they're successful," he said.

Right now, the solutions for greening are focused on managing the vector and keeping its population down by coordinated spraying among several growers in a given area.

The goal is "to slow the progression of the disease so growers can stay profitable and in business as we look toward those more permanent long-term solutions," he explained.

When will that be? It's anybody's guess, but Oswalt is cautiously optimistic.

"Sooner rather than later, but I don't know for sure. I can't predict the future," he said.

Oswalt also runs the Winter Weather Watch program, which provides detailed freeze forecasts for growers based on citrus leaf freezing temperatures. He takes weekly samples of citrus leaves and tests them in a lab to determine their freezing points, because trees can acclimate during the winter. Leaves might freeze at 26 degrees early on in winter but withstand 18 degrees later on.

"We try to provide the information to growers so they can make better decisions on freeze prevention," Oswalt said.

He also writes a citrus newsletter and restarted and grew the Citrus Growers' Institute. The institute is a forum for growers from surrounding counties to get together and discuss issues, given that Central Florida doesn't have a regular citrus trade show.

"I truly do enjoy working with the different growers that are in the Florida citrus industry," Oswalt said. "It's really a unique position, because you get to see breakthroughs in science, and you have the opportunity to provide that information back to the grower to see them succeed."