University of Georgia (UGA) Assistant Professor and Citrus Extension Specialist Mary Sutton reported on the impact of this winter’s freeze on fruit quality and trees in Georgia:
FRUIT QUALITY
A Tango trial was harvested at the end of January as a winter storm was hitting. A subsample was taken prior to that on Jan. 15 and sampled again after the first of the cold weather (Jan. 18-20) on Jan. 23.
A small but significant decrease in fruit size was seen following the freeze. This is most likely the result of the fruit drying out since a significant decrease in juice content was also seen between the two dates.
No difference in fruit color was observed following the cold weather. The fruit had already colored up before temperatures dropped, so it was likely too late for the cold to significantly improve fruit color.
Internally, there was not a significant difference in Brix, although it was a little higher following the freeze. This change is likely the result of the water content decreasing and the sugars becoming more concentrated. There was a slight decrease in citric acid with the cold weather. The resulting fruit had a higher Brix:acid ratio than before the freeze. However, while they still had a good flavor, the mouth feel was definitely off as the juice segments were noticeably dry.
Several people said the fruit picked before the winter storm was much better than what was picked after.
While the fruit were able to stay on the tree following the freeze, fruit quality quickly declined.
Sutton believes if fruit were left on the trees much longer, extensive fruit drop would have occurred.
After the freeze, the fruit were easily hand harvested and separated cleanly from the tree without the use of clippers. Before the freeze, trying to pick by hand without clippers resulted in torn peel and damaged fruit. Therefore, in the case of future freezes, the best bet is still to get fruit off beforehand, especially when prolonged exposure to subfreezing temperatures is forecast.
TREE DAMAGE
UGA is still actively working on freeze evaluations across South Georgia. Thus far, the majority of damage has been seen on young trees. Older trees did see damage along the outer edges of their canopy where freeze protection was weakest.
The worst damage seen has been in locations where freeze protection failed partway through the freeze event. This left trees damp and vulnerable to subfreezing temperatures.
It also appears the freezing temperatures had a compounding effect. Trees that were previously damaged in a cold event appeared to sustain damage in subsequent cold events even when temperatures did not drop as low or for as long as the initial cold event. In these cases, the previously sustained damaged trees were more susceptible to future damage.
Source: Georgia Citrus Association
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