Answer: What a disappointment! There are a number of possible reasons why this might happen. One of the most common is lack of moisture, since raspberries absolutely require a moist soil while they are fruiting. This would equate to about an inch of water a week as a rule of thumb.
Unfortunately, raspberries are also subject to a number of diseases which can cause poor fruit. The most common disease, anthracnose, will cause the berries to dry up as you described. You might wish to examine the plants carefully for any unusual marks or discoloration on the stems and leaves, and if you find any, take a sample to your County Extension for a more definite diagnosis of the problem and suggested control, if any. (Their phone number is 746-1970.)
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