I made a visit to a beautiful blackberry field a few days ago and was shown this example of sunscald, in this case on mature Ouachita blackberry. Notice these are not tunneled, and also one observes immediately that only the part of the fruit facing the sun is affected.
While today it started to become quite warm - thinking it'll be hitting a toasty 80 degrees here before long - this was not the situation when the damage occurred on these fruits a few days ago. More likely, this is a case of ultraviolet radiation (UV) striking and engendering dysfunction in those druplets (the juice filled sacs which compose in aggregate what people know as the blackberry fruit) which are now discolored.
It is not uncommon to see this disorder right around this time of year, coming so soon as it does after the summer solstice, which we all know is June 21 and the longest day of year. Which means the greatest amount of UV exposure of the year for everything outside.
This is also the time of year when I get the most calls about aborted flowers in strawberry, and sure enough one photo already floated into my phone this morning, some varieties are more sensitive to UV. Meaning that the lengthy exposure of flowers to this radiation during the day of and days before and after the solstice is the time that people tend to see this type of damage.
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