Another cold night on Dec. 9 delivered temperatures in the low 20’s for a long duration throughout citrus-producing areas in California’s San Joaquin Valley (SJV), according to California Citrus Mutual (CCM).

Citrus growers are evaluating potential damage to this $1.5 billion annual crop. 

CCM says growers started wind machines Dec. 9 around 8 p.m. in preparation for below-freezing conditions.  A strong inversion layer coupled with frost protection measures helped raise temperatures in the grove by 4-5 degrees in some cases.

The cumulative impact of this freeze episode and the long duration of critical temperatures will result in some damage for the Mandarin and Navel crops.

Preliminary assessments by county agricultural commissioners show damage; the extent of which cannot be determined until the freeze event is over.  

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Mandarins are expected to incur a greater degree of damage in comparison to the more cold-tolerant Navel orange. 

Early fruit maturity and high sugar content will provide some internal protection from frost damage, but the cumulative impact of cold temperatures over several nights is a concern.

The SJV citrus industry has a sufficient amount of harvested fruit on hand to supply the market through the holiday season without impacting consumer prices. 

CCM says industry representatives and government officials are currently developing inspection protocols to keep damaged fruit from entering the market place.   

Another cold night is forecast for Dec. 10. Then, temperatures are expected to increase above critical temperatures.

CCM estimates that the industry has spent almost $29 million since last Tuesday on frost protection measures. 

At this point of the season, 12-15 percent of the Navel crop and 20 percent of the Mandarin crop have been harvested, leaving a significant percentage of the crop at risk for damage.

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