All In With Trunk Injection

Josh McGillHLB Management, planting

Some Florida citrus growers decided to start slowly with trunk injection of oxytetracycline (OTC), treating only a small portion of their acreage. Others took a wait-and-see approach, hoping to learn from their peers’ experiences. But Wheeler Farms went all in, treating 100% of their trees with trunk injection.

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Improved tree performance due to oxytetracycline treatment has inspired Wheeler Farms to plant resets again. Left to right are David Wheeler Jr., Paul Koukos and David Wheeler Sr.

“What we were doing was not working, so we needed to try something different,” says David Wheeler, president of Wheeler Farms.

Wheeler Farms consists of 1,900 citrus acres, with about 75% on the Ridge and the remainder in the Flatwoods. Since trees range in age from two years to more than 20 years, they all were eligible for OTC injection. The treatments took place from March to May after the harvest was completed.

“This summer, we have seen improvement in the groves,” says Wheeler. “Overall tree health is better with increased flush. We are also seeing increased fruit size following the treatment. As of mid-September, we are not seeing fruit drop as a result of greening. Our hope is that drop will be greatly reduced or eliminated.”

He adds that he is very pleased with the response to OTC in trees up to 15 years old and is seeing decent Brix in fruit, which is encouraging. Trees older than 20 years are also responding, but not as well as the younger ones. For the older trees, the Wheelers will continue to apply gibberellic acid in addition to OTC to promote increased flush.

“Two years ago, we stopped removing weak trees. But after seeing early trunk-injection results, it gave us confidence enough to push trees and reset again,” says Wheeler. “We have more hope for the future of the industry now than we have had in the last five years.”

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This tree shows improved health and a fuller canopy after trunk injection.

Since June, Wheeler Farms has planted 10,000 resets in Lake Wales with plans to reset 2,500 trees in LaBelle. The resets represent about 5% of the farm’s total citrus acreage. Trees are Valencia and Vernia varieties on US-942, US-812, Kuharske and Swingle rootstocks.

In order for trunk injection to be deemed successful, Wheeler said the trees will need to hold their fruit until harvesting begins.

“OTC is not a miracle,” notes Wheeler. “It will take time. We expect a bigger jump in production after the second season of application than the first. We would be happy with 200 boxes per acre this season but can get by with a little less.”

What matters just as much, if not more, than fruit yield will be fruit quality. “We’ll need improved quality,” Wheeler says. “Pounds solids per acre is what’s important.”

If trunk injection holds fruit on the trees and fruit quality improves, Wheeler Farms won’t hesitate to move beyond resets and plant a solid set. “We’ll see if fruit holds when we get our first cold front of the season, which tends to shock the trees,” he says.

A decision will be made by the end of the year on whether to plant new groves. Since the Wheelers own 200 acres of fallow land, they have the ability to put in new blocks. First up would be an old, recently purchased 40-acre grove that they would push and replant.

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“My father taught us to look for groves in the path of progress,” Wheeler says. “That’s why we buy groves in need of rehabilitation and turn them around.”

He says if the decision is made to replant, he would like to add some varieties for the fresh market and some late-season oranges. He will also consider applying for participation in the Citrus Research and Field Trial program if it continues to be funded.

In addition to low production due to greening, Wheeler cites his other major challenges as development pressure and extreme weather.

“People make offers on our land constantly, but we are not motivated to sell,” he says. “The weather has been extreme — either really wet, really hot or really dry. There is no normal weather anymore. It has been a very dry summer on the Ridge, while it has been very wet in the Flatwoods, so there is still stress on these trees.”

Drought and excessive rain may limit the full potential of trunk injection, acknowledges Wheeler.

Labor is another perpetual challenge. The farm uses H-2A for harvesting.

One newer challenge is finding lebbeck mealybugs in individual protective covers (IPCs). With the newly added resets, this is the Wheelers’ first time using IPCs.

“We are becoming more diligent with scouting. We’re treating the lebbeck mealybugs and learning as we go,” Wheeler says. “We learned that strong afternoon rains can blow bags off. This happened within two weeks of installing them. They do seem more secure now that they’ve been in place for a few months.”

Helping manage the farm’s challenges is David Wheeler Jr., who joined Wheeler Farms in 2019 as a supervisor. A requirement of a managerial position is to work at least one year outside of the family business and obtain a four-year degree. A University of Florida alumnus like his father, Wheeler Jr. obtained a bachelor’s degree in agricultural communications with a focus on leadership. He reports directly to Paul Koukos, chief operations officer and eight-year Wheeler Farms veteran.

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Trunk injection has resulted in bright green new flush on trees.

“Following in my dad’s, uncles’ and grandfather’s footsteps is something I have always wanted to do,” says David Jr. “It’s a blessing being exposed to all the different aspects of the business — from planting to pesticide application to food safety — and helping with whatever is needed.”

David Jr. also helps run the other family businesses, including apartments, mobile home parks and laundromats. These businesses help provide cash flow to mitigate the risks of citrus production.

“I’m very proud that David has chosen to come into the family business because it’s hard to find young people who want to work in citrus,” his father says. “He is able to adapt to change, and I appreciate his willingness to chip in and help wherever needed.”

David Jr. says what he admires most about his dad is his dedication to his family and employees and his ability to keep the business running smoothly.

“My main goal is to grow and sustain the business for the next generation,” concludes Wheeler.

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About the Author

Tacy Callies

Editor of Citrus Industry magazine

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