The UF/IFAS Tip of the Week shares the signs of freeze damage in citrus as winter and potentially freezing temperatures approach.

Winter approaches, and the UF/IFAS Tip of the Week recommends knowing the signs of Freeze damage in citrus. Published in a Citrus Industry article, they maintain that “temperatures below 20 degrees for more than four hours may kill most citrus trees.” The article shares that chill damage depends on “minimum temperatures, duration of cold temperatures, stage of tree acclimation, tree age, tree health, scion and rootstock, crop load and soil condition.” See the details below.

Signs of Freeze Damage in Citrus

According to the article, “Freeze damage in citrus is due to ice formation in the cell membranes of fruit, leaves, twigs and wood of a tree.” Not all citrus is affected in the same way by cold temperatures. The article maintains that “Sweet oranges and grapefruits are more cold-hardy, but temperatures in the mid-20s will damage even large branches. Tangerines and mandarins are even more cold-hardy cultivars that can withstand temperatures at 20 degrees without significant wood damage.”

Signs of freeze damage in citrus includes:

  • “Dark, water-soaked areas on leaf surfaces.”
  • “Severely frozen leaves are bleached or tan to brown in color.”
  • “New succulent leaves will turn black.”
  • “Wood damage may appear as the scraping of the outer layer of bark. Generally, green tissue refers to live wood, while brown tissue implies freeze-damaged deadwood.”
  • “In young trees, ice formation may result in bark splitting.”
  • “Fruit damaged by freeze may drop.”
  • “The exterior of the fruit on certain cultivars, such as grapefruit, may appear blemished or pitted due to low but not freezing temperatures.”
  • “Fruit easily freezes if exposed to a higher temperature (26 to 28 degrees).”

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