Coryneum blight almost completely defoliated my young (non bearing age) peach trees earlier this season. After I figured out what it is was (by folar identification) I was able to get my peaches back growing again. Here what I learned and what I did to get my peach trees back growing again.
I checked my soil PH around each peach tree with a calibrated soil PH meter to the depth of normal moisture. My probe reading were consistent 5.8 - 6.2. Over the course of a full week, I watered in well powdered barn lime and checked the soil PH the next day to a depth of normal moisture. It took 3 applications of barn lime to raise the soil PH to 6.5 - 6.7 at normal moisture depth. In hind sight I wouldn’t have changed this approach at all because I had no idea how much barn lime to add. So I would add a little at at time and it worked well.
week two I applied just nitrogen fertilizer and after several days I could see buds breaking I was relieved and happy I was able rescue my peach trees. But wait a minute it was not over yet!
As the leafs started to regrow, I could see Coryneum blight reemerge as red circles that became purple and grew to the point where the centers fell out giving the leafs a ragged shot hole appearance.
Not going down with out a fight! I sprayed the maximum allowable rate of copper octanoate (copper soap) and much to my surprise it worked and worked well . I have since followed up after 10 days and sprayed copper octanoate again this time at its minimum allowable rate. And it appears I have gained the upper hand, at least for now anyways. But any sign of coryneum blight will be delt with swifty with a spray of copper octanoate!
What I learned about Coryneum blight can best be summed up in the PSU article below. If you to spot it, it really needs to be addressed sooner rather than later, before it defoliates the tree, like it did mine.
Please contribute to this thread, help others win their battle against coryneum blight!
I sprayed my plum trees early this am while temps were low, how many days did it take before your foliage began to come back. I had Monterey Liqui-cop so I used that. Its instructions advise reapplication in 7-10 days. Some of my leaves are folding rather than curling and some have shot holes. Some in first pic just dried up no holes or shot holes. So I think I have several infections going on.
Dennis
Kent, wa
That doesn’t look like shot hole (Cornyeum blight).But it took a little less than two weeks before the foliage buds to break. Do your tree have ample water? They appear dehydrated? do you have moles/voles?
I don’t think water is the issue, in the first pic all other scaffolds on this tree appear healthy. In the second pic an adjacent tree all foliage is healthy. All are watered once a week.
Dennis
Since my last posting I have sprayed all my plum trees within 60’ of the ones that defoliated twice with liquid copper. Also .fertilized with a dose of ammonium sulfate and spread a compost and chicken manure mulch around each defoliated plum tree. I noticed today that new foliage is emerging on the majority of my defoliated limbs, even had a potted fig tree that dropped its figs and foliage but is now after faking dead putting out new foliage! I still have no idea what caused the defoliation that on several plum trees lost life in several scaffolds. We have had an unusually long hot spell without rainfall but since my trees are mulched and I water weekly, it’s some what of a mystery. I believe the copper sprays helped although it’s also seemed to cause more defoliation. I need to find a good all purpose fungicide for use during this next dormant season. If you have any idea what could cause this type of defoliation of otherwise healthy plum trees let me know.
Dennis
Kent, wa
If multiple trees are getting affected I can’t think of anything else but herbicide. Some herbicides get into vapor form and can reach quite a distance. Other guess is verticillium wilt probably.
I was relieved and happy I was able rescue my peach trees. But wait a minute it was not over yet!
. I have since followed up after 10 days and sprayed copper octanoate again this time at its minimum allowable rate. And it appears I have gained the upper hand, at least for now anyways. But any sign of coryneum blight will be delt with swifty with a spray of copper octanoate!
