Arbico does have a nematode for pearl or ground scale they call it nemaseek. Two applications between mid May an mid June for best results.
An old timer told me to mix up some (6-oz) TSP tri sodium phosphate in a hose end sprayer with some (see label)Dylox and set the sprayer for 2-oz per gallon and saturate the area effected and 12'-18" beyond, be prepared the turf will brown out. Then water in deeply.
Obviously this is not a by the book technique but it will knock them out. I have been told TSP can be found at H/D, Ace, Lowes etc in the plumbing isle. Let me know how it works if you try it out.
Let the flaming begin I am satin, I am the cause of the ruin of our ecosystem bla bla bla. Hey I started out with the organic control but lets face it we are in a results oriented business if you notice the scale in Aug. when it usually shows up. The client doesn't want to wait until may next year to take action.