Growers in the U.S. are utilizing the citrus under protective screen (CUPS) system to shield trees from the Asian citrus psyllid, the vector of HLB disease. While grapefruit is predominantly cultivated in CUPS, statistics suggest its potential for other citrus varieties.
Arnold Schumann from the University of Florida Institute of Food and Agricultural Sciences highlights the need to define the requirements for different citrus varieties. "Most of the CUPS commercially grown is grapefruit. It has been very successful, but there's a desire to have other varieties," he stated. Efforts are underway to broaden the range of citrus grown in CUPS and ensure quality.
Valencia oranges have demonstrated "excellent quality" under CUPS, according to Schumann. "We have mature trees of Valencia that are 10 years old. The fruit was harvested in March, which is typical Valencia season. Total soluble solids (TSS) were 13.9 degrees Brix. Acid was 0.63%, giving a ratio of TSS to acid of 22. That amounted to 7.2 pounds of solids per box," he explained. Younger Valencia trees produced a TSS of 8.5 with an acid of 0.46% and a ratio of 19.
Schumann noted that another CUPS advantage is the absence of fruit drop, unless the variety is prone to peel cracking. Research shows positive outcomes with varieties like Sugar Belle, Temple, Dancy, and Early Pride, barring splitting issues.
For growers considering CUPS, Schumann advises focusing on proven varieties. "If I were to invest in CUPS, what I would do is put the majority of it in a reliable variety that's proven like red grapefruit; let's say 75%," he said, suggesting the remainder be allocated to promising but riskier varieties.
Source: Citrus Industry