Yep, brown rot.

Nectarines are extremely prone to brown rot- probably the main reason peaches rule in the east.

Wet spring in CA? You by the beach or inland?

Was that with or without an anti-fungal spray?
I've experienced that with peaches and multiple rainy days before harvest - I feel your pain!

May not be too late to spray the rest.

I'm inland. That's without anti-fungal spray. We had 90 degree weather followed by a day of torrential rain, followed by 90+ degree weather, I think it was the first week of June. I'm guessing that's what did it, never had a brown rot issue before. So very frustrating! Is anti fungal spray worth using?

Thanks for the help, gang!

The sterol inhibitors have serious kick-back and can rescue fruit not yet ruined. The only SI I know of available to home growers is Monterey Fungus Fighter. I use Indar but it comes in big jugs that can treat acres and acres and runs around $300.

Kick-back in a good way? I'll find some. Thanks!

The active ingredient is propiconazole, which is also available to home growers as Infuse concentrate, which isn't the same as the Infuse lawn product, thiophanate-methyl.

Spray with Fungi Fighter at the first sign of Brown rot. It will usually do a pretty good job of stopping it in its tracks. I usually give a spray about a month before the fruit ripens as a preventative.

Do any of the big box stores carry Monterey FF?