FROM THE FIELDS: HEAT-RELATED ISSUES IN DESERT CROPS
February 20, 2015
The Arizona/California desert growing region has experienced temperatures that have been 9 to 15 degrees above seasonal norms for the past 18 days. Highs have climbed to as much as 90 degrees in isolated areas, but the majority have been in the mid- to upper 80s.
Temperatures will return to seasonal norms over the weekend and throughout most of next week, February 23 to 27, but the prolonged heat has already had a noticeable effect on iceberg lettuce crops in particular. Markon inspectors have been reporting the following defects:
• Growth cracks
• Inconsistent or dense texture
• Insect pressure
• Mildew pressure
• Protruding ribs
• Ribby shape
• Rib blight
• Sun scalding
Some value-added leaf lettuce and tender leaf crops are also experiencing several of the above-mentioned quality concerns and will likely exhibit shortened shelf-life from heat stress. Harvesting and processing crews are heavily trimming product in order to better detect and avoid serious defects, but will not be able to eliminate all issues completely.
Ordering for quick turns is recommended; maintaining the cold chain throughout distribution is critical to maximizing the quality and shelf-life of commodity and value-added produce items.