Close examination of my young trees shows that they have become host to a hard structured insect.  They don't seem to move but are tended to by the ants that are shown in the pictures.  What should I spray the tree down with to kill them.

I completely cleaned out the greenhouse and hosed it down with Seven so the ants are history.  It looks as though the ants were taking care of the brood but whatever they are they were completely covering a limb and several leaves.  The pictures illustrate my findings.  All input is welcome.    

Scale.  The ants tend them and protect them and in return the scale give them honeydew, an excretion from their bodies.  I just smash them but you have a lot more than I ever get.  

Scale

yep, scale, you can get rid of them by spraying the tree with alcohol or with neem oil , both will work.

Go on vacation and the whole family moves in!  I will get some neem oil today.   Or I might try the alcohol method if I can't find the neem.  Thanks for the identification of the pest...

give neem oil a try first, spray it on the tree and scrape off the little buggers. You may need to reapply in a week or so but that should do it.