Help Identifying Growth on Korean Hornbeam

[99 Mile Creek]

This is the second time I've come across this 'growth' on this specific Korean hornbeam.

It's a hard shell-like nest or growth. Gloss on the outside much like a ladybug. When broken open, white dust blows away.

The leaves started going brown in spots like this late last year (August), the leaves falling earlier than I expected. I think the leaves are being eaten by something. The foliage was completely fine a month ago, too.

Water habits are about once a day. But I water when I feel it's required. It stays under shade cloth to keep from the high sun of a south-facing backyard. I repotted early this year in a substrate mix that most of my others are in. All other trees are great.

Anyone know what this could be? Insect of some kind?

 

[Deep Sea Diver]

Quite possibly Cyrospora canker. Can infect areas where branches have been pruned.

If so, here’s a quick rundown on potential treatment.

Once infection occurs, the best treatment is to increase plant vigor and sanitation. Remove all infected limbs and other areas. Clean wounds to avoid further spread of infection. Remove dead bark to dry out the diseased area and help the tree defend itself against insect and fungal attacks on the cankered area.

Cheers
DSD sends

 

[99 Mile Creek]

Quite possibly Cyrospora canker. Can infect areas where branches have been pruned.

If so, here’s a quick rundown on potential treatment.

Once infection occurs, the best treatment is to increase plant vigor and sanitation. Remove all infected limbs and other areas. Clean wounds to avoid further spread of infection. Remove dead bark to dry out the diseased area and help the tree defend itself against insect and fungal attacks on the cankered area.

Cheers
DSD sends

Hmm...this was located on the middle of its trunk, so removing branches can't happen.

Perhaps cutting away the infected area, scraping the bark around it a little further and alcohol application?

I did go ahead and apply BioAdvanced 3 in 1 insecticide and plan to repeat in ten days.

From what I gather, the fungus can be a sign of an underlying issue.

It very well may have not liked the rapidly drying mix of akadama, lava, and pumice (or my watering habits with the new substrate). I took off an inch from the top of the trees' substrate I planned to exhibit this year (this one included), added a bit of peat and sphagnum to the current mix and topped it back off. Should help retain a bit more water while I start adding moss soon. Though noteworthy, not entirely sure if this the issue as the other trees have been fine in this mix.

There was also a spider web just under the shade cloth where I keep the hornbeam. I cleared it out, sprayed the underneath of shade cloth with the 2 in 1. Maybe spider mites? Lot of variables.

Thanks for the direction. Hopefully this clears up with my current plan.