The cranberry season could extend beyond the year-end holidays this year thanks to the work of a new adjunct professor at Washington State University in Mount Vernon near Seattle.
Frank Caruso recently retired after 28 years at the Massachusetts Cranberry Station and is conducting disease research for Washington cranberry growers in hope of giving their product longer shelf life.
"Growers can lose up to 30% of their crop to rot which is most often caused by fungi," he observes. "That's a significant loss. The ultimate goal of my research here is to help growers reduce that percentage of fruit loss."
He is probing which fungi species are contributing to rot in the field and in storage. Cranberry samples are sent to him at regular intervals from six southwest Washington production beds: three for berries sold fresh and three for processing types. He follows the progression of fungi found in the berries throughout their development and ripening from August through November.
"What I'm finding so far are significant differences in fungal populations in all six beds," he reports. "One fungus I'm finding a lot of, that is not a major player on the East Coast, is Collectotrichum acutatum, which is a major pathogen of numerous fruit crops."
Once the fungi are identified, Caruso will correlate his findings with growers' fungicide applications. This may help determine what changes are needed in management to reduce loss due to rot in the crop.
"We know that Abound fungicide works well on Collectotrichum, acutatum, but there's another strain – or perhaps a different species – that I'm having analyzed right now. I'm finding it at higher levels in the fresh fruit beds."
Caruso says he doesn't know what significance it has in these circumstances, so the next steps will be to identify, isolate, inoculate and prove it causes fruit-rot disease, he explains.
"Then, growers will be able to make choices on how best to respond."