Prunus Caroliniana - trunk oozing and leaf problems

Trunk sappy seepage, this is present on
all trees showing signs of the problem

When I bought my house I knew I was going to plant a perimeter of "Carolina Cherry" (prunus caroliniana) to create privacy and shade.  My parents had experience with the trees and they seemed perfect

I purchased 70 15 gal trees at a killer price and had them in the ground the first year.  Over the past 5 years I have lost 9-10 trees and I fear I'm going to lose even more.  The symptoms are a yellowing and red color blotching of the leaves and seepage on the lower 30% of the trunk.

I never water these trees because I've been told by so many people that they were getting TOO much water, so I just left them be and the rain seemed to be enough.  I should mention that the majority of my trees look great, dark green and reaching for the sky.

There is also some obvious insect damage but I think it's most from the Japanese beetles that I have flying around, I don't think it's related to the trunk and leave problem.

Once the problem enters the advanced stage the leaves will drop very rapidly, finally they will look wilted and droopy and that is usually when I cut the tree out.

I hired an arborist to come out 3 years ago and look at some problems and he was useless, all he said was "Well... it could be this and it might be that.  It's hard to say"

What the HELL am I paying you for??!!

At this point I'm ready to spend some money to get an accurate and concise assessment of the problem and clear instructions on what to do about it.  I just need to figure out who to call...