There is a blackberry bush in my garden, UK, its fruit is ripening at the moment, but many of them are discolored. I read that sunscald could be one cause, it does get direct sun for a lot of the day, and unfortunately I cannot move it as its too large. I have also wondered if it could be insects, but so far the only insects I have seen on the blackberries are one or two spiders, and what seems to be ants, who apparently only feed on already damaged blackberries. I have seen that the ants bulbous part on their body looks see through or partially see through on some them, but they do look just like ants. I have taken photos of the discoloration as well as the ants/insects. Is there any way to save the blackberries that haven't ripened yet? Some of the bunches of blackberries look almost 100% black like they should be, but many are like in the photo. thank you
You may have a problem with raspberry beetle, which does affect blackberries too - it causes parts of the berries to dry up, as yours have done, although I've never seen whole berries so badly affected. Sunscald in the UK doesn't seem likely, but actually, the recent heatwave may have had some effect, though as its so recent, I suspect not. Its worth cutting open a few of the affected fruits, both those which are completely dry and those which are partially dry to see if there's a grub inside, which would confirm the presence of this pest. Information below
There is some possible evidence of red berry mite too, which causes uneven ripening of fruits, but that's difficult to identify for sure because its still relatively early and the fruits may not yet have fully ripened anyway. Information regarding this pest here
As for the presence of ants, they might be after damaged fruits for the their juice, or they may be present because of aphid infestation on the plant, so a close inspection to determine whether there are aphids anywhere is a good idea.
You've got a heat problem, this is UV damage or excessive heat during the ripening phase and referred to as White Drupelet syndrome (white spot). It's quite common on Raspberries during the final crops of the year as summer heat increases. Also occurs in blackberries. Last year, we had issues in the US Pacific Northwest with it, only a handful at end of season this year as we've had a cold, damp summer.