Autumn Blaze Maple issues

[Hattereno]

When we built our home, we had 38 Autumn Blaze Maples planted among endless amounts of others.

Issue #1: Last summer, after 2 years, I noticed die off on a half dozen trees only to find a serious problem with scale. I treated ALL of the trees with CoreTech tree and shrub tablets. Then I sprayed the trees down with an insecticide to fight the scale. I had to dramatically cut a couple of the trees because the amount of dead in them was overwhelming.

The scale is back this year, even though the tablets were supposed to work for 2-3 years. I'm worried about the lack of growth. What else can I do to rid the trees of scale? I planned on using a Bayer systemic, but wanted some valid advise.

Issue #2: Of less importance, though it may indicate another dying tree, I have one with the bark separated at the base. There is a black powdery looking residue coming out of the cracks in the bark. I can't find any information on this type of bark disease. Any ideas?

Thanks so much for your help!

 

[Raintree]

Number one issue I see with planted trees are that they're in the ground too deep. Check your root collars.

Do you know what type of scale, soft or armored?

 

[Hattereno]

Do you know what type of scale, soft or armored?

Armored Scale.

 

[Raintree]

Armored Scale.

The most effective treatment I have used bar none for armored scale is Safari insecticide.

Hit them hard with Safari one time only, then do a maintenance Hort oil app. until no longer needed.

 

[Hattereno]

Do you recommend spraying the branches or the trunk? The instructions on Safari have both options. Branch application uses 1 tsp/gal while trunk uses 12-24 oz/ gal. This is a huge spread. Thanks for the advise!

 

[Raintree]

With smaller trees it's easy to get real good coverage with the spray at the lower rate.
I would go with that.