Prunus Leaf with Shot hole disease

[junmilo]

Hi,

So found some shot hols on some of my ume. what would you guys recommend as a chemical treatment?

Thank you

Jun

 

[cbroad]

I have experience with it on cherry laurels, so assuming you have the same disease, any copper based fungicides should work, and I think mancozeb also. But the issue could be more environmental.

I'm used to seeing it on nursery stock laurels, where we have hundreds crammed into small spaces and are over head watered at night... So for us, our biggest issue was poor air flow around the plants coupled with water bouncing from plant to plant and the foliage staying too wet.

Not saying you have those issues, but if that could be the case, I'd try to fix that situation and use a couple applications of a fungicide.

Good luck!

 

[junmilo]

Here are some photos of what it's experiencing..

 

[cbroad]

I have zero experience with Japanese flowering plums/apricots so I'm not too sure about your trees specific issue, whether it is definitely shot hole or something else, sorry.

But knowing prunus in general are pretty susceptible to a lot of fungi and diseases, I would keep on a good spray schedule. Probably really important is a dormant spray sometime in the winter, but I'm not sure when to apply, before or after blooming, I'm guessing before???

Hopefully someone with more experience will chime in.

 

[Leo in N E Illinois]

I don't know, I can't find a listing for "shot hole disease". My reference is the "2017 Michigan Fruit Management Guide". By Extension Service of Michigan State University. The guide describes what is legal and recommended for fruit crops in Michigan. Basically, if you are a farmer, if you spray something not listed for your crop, you are prohibited from selling that fruit.

For leaf spot disease, prunes & plums, use Rovral 4 (1 -2 pt per acre)
Tilt 3.6 EC (4 fl.oz. per acre) has only fair results
Captan 50WP (6 lbs per acre) good effect.
Pristine 38 WG (10.5 - 14.7 oz per acre) fair effect.

I didn't look up active ingredients for the trade names.

I have limited experience with ume, plums or cherries. All mine died over the years.

 

[cbroad]

Here's a link to a wiki page about it. Could be pretty bad in some cases where it affects every above ground plant part. Though, it seems it's more of an issue with fruit production trees, where it can destroy whole crops if left unchecked.

 

[junmilo]

Thank you all,

I will see what I can find here up north.

Kind Regards,

Jun

 

[shinmai]

Shot hole disease is more commonly known as corundum blight. It’s a fungus that usually pops up after several days of rain. My apricot had it this spring. The best treatment is defoliation (leaving leaf stems attached) and spraying the tree and the soil surface with Fungonil. Do so twice, a week apart, and keep it out of direct bright sun until a healthy amount of new foliage begins to show. This is what I did, and mine came back and is thriving beautifully. Best of luck.

 

[shinmai]

Damn you, auto-complete! That should have been 'coryneum' blight. All else remains accurate.

I shouldn't feel too bad, though--I know someone who was sending a message regarding his elderly, unmarried aunt. Auto-complete changed 'spinster' to 'sphincter'. Bet that made for an interesting family holiday dinner.