When is it too hot for prunes?

In the photos, from the top: Cyndi Gilles of the University of California Cooperative Extension office in Red Bluff tags a plum blossom; a gauge records temperature and humidity; and Gilles talks with UCCE farm advisor Rick Buchner.

Multiple Cooperative Extension offices up and down the valley are involved in a multi-year study to see what happens to blossoms of plums grown for prunes if they get too hot. So far, it looks like 80 degrees is the cutoff; any warmer and the flowers dry out and the fruit doesn't set. The prune industry has had three disappointing crops in the last 10 years because of unseasonably warm temperatures during the bloom, although that doesn't seem likely to happen this year.

For my story, check CapitalPress.com early next week.