Have some serious black knot on my mature santa rosa plums.Tried pruneing the trees this winter after first sign,since leaves and fruit are on trees really turned serious. Seems 1 tree is worse than the other 2 . One tree has none yet.
Im sure it will soon enough.It seemed the more i disturbed the knot ,the worse it got.
I also have 35 apple trees very close in same orchard that I will soon spray for apple rust.Is there a spry on the market I should ck into. thank you, buddy