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USDA Assesses Freeze Damage of Florida Oranges

A Florida orange showing evidence of freeze damage at the center cut. Cell walls have weakened and separated, leaving a hole from which juice can seep out and evaporate.

A Florida orange showing evidence of freeze damage at the center cut. Cell walls have weakened and separated, leaving a hole from which juice can seep out and evaporate.

This post is part of the Science Tuesday feature series on the USDA blog. Check back each week as we showcase stories and news from USDA’s rich science and research portfolio.

This year’s weather has presented some challenges for Florida’s citrus growers. In December, sub-freezing temperatures hit the citrus-growing region in the state, threatening this year’s citrus crops, which account for more than half of all citrus production in the United States.

To measure the cold weather’s effect on citrus crops in Florida, on Jan. 10-11 USDA’s National Agricultural Statistics Service (NASS) representatives visited 240 orange groves and 90 grapefruit groves across Florida’s citrus producing region. These crews went to randomly selected trees to cut and score fruit to determine the extent of freeze damage. In each selected grove, two pieces of fruit were selected from each of four trees.

Establishing the extent of the freeze damage required a sequence of steps, which followed the Federal-State Inspection Service standards. To determine the damage severity, our crew members cut off the outer quarter inch of the fruit to look for damage, then cut off the next quarter inch, and finally, cut the fruit at the center.

NASS found evidence of freeze damage in about 28 percent of the early season and midseason oranges and 13 percent of the late season varieties. For early and midseason oranges, 12 percent had damage at the center cut (the most serious damage). Just over two percent of the late season oranges had damage at the center cut. For grapefruit, only three percent of the tested fruit were damaged. Less than one percent of the grapefruit had center cut damage.

The full set of the results were recently released in a Florida citrus report and can be found online.

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