At a recent field day for citrus under protective screen (CUPS) in Polk County, researcher Arnold Schumann discussed varieties that appear to work well in the system. Schumann is with the University of Florida Institute of Food and Agricultural Sciences Citrus Research and Education Center. The primary purpose of growing citrus under protective screen is to keep out the Asian citrus psyllids that spread HLB disease.
Schumann pointed out that seedless fresh fruit varieties that consumers prefer are high on his list of favorites for growing under screen. “It needs to be able to grow seedless in the CUPS … in the absence of pollinators but still produce fruit,” he noted. He added that “earliness is important” so fruit is harvested prior to freezes.
Temperatures in CUPS are about 6 degrees warmer on sunny summer days than temperatures outside the screened facility, and about 3 degrees warmer on sunny winter days, Schumann said. So varieties need to be heat tolerant.
At night, temperatures inside the facility are about the same as outside. Schumann said this is a good thing because “you accumulate the chill hours which all citrus needs to form the buds for flowers and bloom.”
Schumann’s list of favorites for growing in CUPS includes limes, Early Pride, Meyer lemon, Ray Ruby grapefruit, W. Murcott and Honey Murcott, Bingo, BB4 (unreleased mandarin), Sugar Belle and the 914 hybrid of grapefruit and pummelo.
Hear more from Schumann:
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