Fine-Tuning CUPS Production Practices

Josh McGillCUPS, Production

Mixon family members were pioneers in the Florida blueberry industry. Brothers Jerry and Keith Mixon planted their first berries in 1993. Over the years, they grew their business and became worldwide marketers, eventually adding blackberries, raspberries and strawberries to their portfolio.

Jerry Mixon in his CUPS, which have protected trees from Asian citrus psyllids and HLB. (Photos by Frank Giles)

In 2011, they sold their berry business to the Dole Food Company. But the brothers still had the farming bug and began searching for new enterprises.

“We needed something to do. I was too young to retire,” says Jerry Mixon.

About the same time the brothers exited the berry business, Arnold Schumann, University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) professor of soil fertility and water quality, was beginning his research on citrus under protective screen (CUPS). Schumann built an experimental 1-acre CUPS at the Citrus Research and Education Center in Lake Alfred to study if the structures could exclude the Asian citrus psyllid and HLB.

“We had citrus prior to blueberries and were interested in making a positive impact on the industry that had been so impacted by HLB,” Jerry says. “The structure Dr. Schumann built used a pole and cable design, which I immediately connected with because we had experience building these to protect our blueberries from birds. It was something we knew how to do, so we began studying CUPS more closely.”

Jerry and Keith Mixon now have 150 acres of CUPS with plans for expansion in the works.


Jerry installed his CUPS in Alturas and planted W. Murcott and Sugar Belle. His CUPS plantings have grown to 70 acres with plans on the books to add more.

Sugar Belle has since been phased out, and he is closely evaluating other varieties that may replace W. Murcott soon.

“I was really wanting a tangerine to be the kicker, so we took a chance on W. Murcott,” he says. “With the Sugar Belles, we could never get the quantity or quality we needed. I want to diversify our varieties, but we’ve not yet zeroed in on a variety we have full confidence in.”

Jerry has about 21 different varieties under evaluation in his CUPS structures. He says several grapefruit are being considered, and Early Pride looks promising.

“I wish we paid closer attention to the success Dr. Schumann was having with grapefruit — even early on in his research,” says Jerry. “As we phased out the Sugar Belle, we replaced them with grapefruit. The Early Pride look beautiful and are blooming like crazy, so that gives us high hopes.”

As for rootstocks, Jerry says most growers with CUPS are using US-897, himself included. US-897 has a dwarfing effect on the size of the scion tree. It also induces good yield productivity per canopy volume of the scion tree. Planting density in the CUPS is 400 trees per acre.

Keith built his CUPS in 2018 in Alturas on 80 contiguous acres. Half of the acreage went to tangerines, and the other half was dedicated to grapefruit.

“I want to grow beautiful, great-tasting fruit with high production per acre that is produced efficiently,” Keith says. “Fruit that is considered an item of distinction in the market can be produced in CUPS. We are testing several other tangerine varieties hoping to find those that work best in CUPS and in the marketplace.”

Sugar Belle has been phased out and replaced with grapefruit.


Jerry didn’t have to wait long for his CUPS to be tested by Mother Nature. In 2017, Hurricane Irma caused extensive damage to his structures. He says the storm was a learning experience and emphasized the importance of having a hurricane plan.

“After Irma, we didn’t have backup materials or labor lined up for the repairs. It took us 14 months to get everything rehabbed.”

Last season, Hurricanes Ian and Nicole damaged his CUPS, but he was much more prepared for the aftermath of the storms. “Ian gave us the biggest whack, and Nicole was kind of like an aftershock to an earthquake. It probably added another 10% to 20% damage in some places.”

Jerry says some of his CUPS suffered 70% to 80% damage from last year’s hurricanes, particularly the tops of the structure. But the cleanup and repairs went much more smoothly. Luckily, no poles were broken by the winds.

“I am pleased to say between my brother’s and my CUPS, we had our structures repaired and rehabbed by Christmas,” he says. “We had backup mesh netting on hand. That is very important because mesh is a long-lead item with easily a 90-day turnaround. And that’s without a hurricane. Any grower considering CUPS needs to factor having backup materials into their financials.”

Jerry says the backup materials are like an insurance policy. He also carries the U.S. Department of Agriculture’s Hurricane Insurance Protection – Wind Index endorsement. This year, the agency has added tropical storm coverage, which he will be looking into to see if it’s worth the investment.

A benefit the brothers observed after last year’s storms was that there was no tree loss or fruit drop in the CUPS. The structures provided windbreak protection, and perhaps because the trees were healthier and HLB-free, they held fruit better.

Jerry Mixon inspects a strong bloom under the protective structure.


One of the primary benefits of CUPS is psyllid exclusion to prevent HLB infection. Over the years, the structures have delivered on that mission.

The brothers utilize a third-party scouting service to check for psyllids and other pests once per month. That frequency was increased to every two weeks after the hurricanes, due to the fact trees were exposed to the outside from damage. So far, no trees have shown signs of HLB infection, but the scouts will be looking for it. Jerry says if a tree is infected, they will treat it with the new oxytetracycline trunk-injection therapy.

Other pests small enough to get through the 40-micron mesh include leafminers, thrips and mites. Citrus canker can make it through the mesh but doesn’t thrive in CUPS. Greasy spot and melanose must be monitored and treated with labeled fungicides. 

“We had an outbreak of lebbeck mealybug after harvest this past season,” Jerry says. “I think the harvesters spread it around to several different spots in the CUPS. We’ve been working with UF/IFAS entomologist Lauren Diepenbrock to develop a management program. We are getting them under control and have a better plan for addressing them in the future.”

The fertilizer program in CUPS is being fine-tuned, but Jerry says it is nice to have healthy trees in the ground that fully respond to applications.

“We follow the UF/IFAS production recommendations for fertilizer, but we are learning the specific needs of each variety and adjusting our program accordingly,” he says. “The nice thing with CUPS is your cost per pound or piece of fruit is significantly less than outside production, because you are getting much higher production from the inputs applied under the cover.”

Jerry Mixon is evaluating about 21 different varieties in his CUPS structure. He top-works the trees to speed up the evaluation process.


Jerry advises growers to have a marketing plan prior to installing CUPS. A strong marketer with significant reach is a benefit that will allow a grower to expand. Jerry markets his fruit through the Dundee Citrus Growers Association. Keith markets his product through W.G. Roe & Sons/Noble Citrus.

“My goal with CUPS was to have the ability to produce a really great-tasting, high-quality piece of fruit that could compete with anyone around the world. We are still learning, but I think we are achieving that with our structures,” Jerry says.

“We are happy with CUPS. Every year we look to improve all aspects of production, but we truly believe we can produce great-tasting and great-looking Florida fresh fruit,” Keith concludes.

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Frank Giles


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