|The bush and green blueberries look fine but the berry is swiveling as it turns blue. There are other blueberries (other varieties) close that are doing great. What is a possible cause of the berry drying up as it ripens?|
|It's difficult to diagnose without seeing the plant but it sounds suspiciously like Anthracnose Fruit Rot, caused by a fungus called Colletotrichum gloeosporioides. Infection can occur any time between blossom and ripening. Usually fruit is infected while it is forming, and the fungus remains dormant until the fruit begins to ripen. The first fruit symptom, seen when the ripening fruit is beginning to turn blue, is a soft, sunken area, usually on the blossom end of the fruit. If the weather is humid, the spots will produce bright pink or salmon-colored slimy spots, which are the spores. There is no cure once you discover the problem but you can help prevent it next year. Prune out small twigs and older canes, to improve air circulation. Prune out any diseased wood. Some varieties are more tolerant of this disease than others, but none are completely resistant if the weather is favorable for this disease. Preventive fungicides will help control the problem next spring and they are most effective when applied from pink bud to harvest, in particular between bloom and pea-size green fruit and when the berries start to turn blue. You can use lime/sulfur or Captan, according to label directions.
Hope this information is helpful.