Plum tree, bark stain, curled leaves, insects

[Dale1995]

Was brought to my attention that one of the plum trees in the yard was dying. (My landlords mom in law accused me of killing it)

I went and took a look at it and I'm seeing thousands of mostly dead ?white aphids? and black stains on the bark. The insects are on the bark, leaves everywhere. The dark stains are on about half the bark on branches and trunk alike.

I did some truck work about 2mths ago and I inadvertently spilled a few quarts of diluted antifreeze, about 1 qt of transmission fluid and like half a qt of engine oil. This was on dirt about 6ft from the plum tree. When doing this repair I hung the driveshaft in the tree branches. Not my intention but about 1oz of transmission fluid I didn't know was in the driveshaft leaked down the tree. I know all the stains aren't from this because the stains are way higher up then I put the shaft.

Just included this so all information was available. I'm pretty skeptical I caused this but as I'm pretty clueless about gardening I couldn't rule it out 100%.

 

[Dale1995]

Wanted to add that it's apparently a special Italian Blue Plum tree? That's what I was told. Wanted to add this in case it made a difference. I would love to be able to fix this for them if it's not dead already

 

[Gumneck]

Malathion or Imidan will knock out the aphids or bugs on it. Killing them will be a good start to give it a chance. Some other pics of the overall canopy would help to see condition.

 

[Dale1995]

Here's some canopy pictures. Hopefully they're decent quality. The close up is of the plum tree from top

 

[Gumneck]

@Dale1995 From what I can tell, it looks like the tree has plenty of new green growth. Doesn't look like a dying tree to me.