Q. My apricots were doing very well as they have for the last several years. After thinning a large crop this year, they were growing very well and appeared to be getting ready to pick when I opened the cots, I found the insides to be rotting. I've tried to do a little research without success.
A. This may be ripe fruit rot, sometimes called Brown fruit rot. It can happen if there is rain near the time of harvest. We get other diseases on fruit as well if there are rainy periods at different stages of fruit development.
There is not much you can do except hope that rain does not occur at that time. Here is some information from the University of California. See if this description matches your problem.
They recommend fungicide applications earlier in the season to present it but we get such a little chance of rain here to me it doesn't make any sense to make these applications. Just figure this year you had some losses that come along very infrequently.