I apologize if this same question is asked already. I looked but didn’t see it already asked. Does anyone what these spots are, what may be the causes or how to treat?
Possibly fungal? Search needle cast and general fungal treatments for Bonsai. There are several fungi that attack JBP. Best protection is to protect and prevent infection on the new needles with a preventative fungicide spray. I also have used a granular systemic, but I’m not sure if the pines can uptake it on a reasonable timeframe and the effect on mycorrhizae.
Thanks! I also checked with another local bonsai buddy and he thinks it might be needle cast and recommended treating with Daconil. I have started treatment. We’ll see, hopefully that contains it from spreading to new candles.