Frozen Citrus Fruit and Young Trees

Dec 11, 2013

Evaluating Damage to Baby Trees Requires Patience

Earlier temperatures and forecasted temperatures do not appear to be cold enough to freeze baby trees in the citrus belt. Time will tell. Semi-dormant wood in the winter looks dry even when it is healthy, so any final evaluation should be conducted in the warmth of spring. With warmer temperatures, frozen bark will peel easily from the young trunk and the degree of damage easily estimated. A tree, even those frozen down to the top of the wrap, can make an amazing recovery. Growers, in the summer after the 1990 freeze had some success budding onto the rootstocks that remained after the scions were killed by frost.

It may be better to replace a tree if it is still alive under the trunk wrap but badly damaged. Badly frozen trees regrow fairly slowly, and often are not able to resist pathogens that grow into the wood such as fungal Fusarium species causing dry root rot. Slow growing Fusarium in the wood can take up to 10 or 15 years to kill a tree.


Badly Frozen Young Trees

Badly frozen fruit may start dropping from the tree shortly after the freeze, but other fruit may hang on the tree longer than unfrozen fruit. Many growers resist picking or dropping frozen fruit in that it is another expense, at a time of little income. Reasons for dropping the fruit, even if it cannot be sold for juice, include:

Ensuring that the frozen fruit does not interfere with spring fruit set. Navel oranges, for example, will not set as much fruit if last season’s fruit remains on the tree.

Old frost-damaged fruit may harbor fungal pathogens that may infect the new crop, such as clear rot (Penicillium sp.), tear staining (Colletotrichum sp), brown rot (Phytophthora sps.) or Septoria organisms.

Avoiding having to separate last year’s partially frozen fruit from the new crop at harvest next year.

Preventing partially frozen fruit from providing habitat for insect pests.